tor-browser

avcodec.h (145987B)

---

/*
* copyright (c) 2001 Fabrice Bellard
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

#ifndef AVCODEC_AVCODEC_H
#define AVCODEC_AVCODEC_H

/**
* @file
* @ingroup libavc
* Libavcodec external API header
*/

#include <errno.h>
#include "libavutil/samplefmt.h"
#include "libavutil/attributes.h"
#include "libavutil/avutil.h"
#include "libavutil/buffer.h"
#include "libavutil/cpu.h"
#include "libavutil/dict.h"
#include "libavutil/frame.h"
#include "libavutil/log.h"
#include "libavutil/pixfmt.h"
#include "libavutil/rational.h"

#include "version.h"

#if FF_API_FAST_MALLOC
// to provide fast_*alloc
#include "libavutil/mem.h"
#endif

/**
* @defgroup libavc Encoding/Decoding Library
* @{
*
* @defgroup lavc_decoding Decoding
* @{
* @}
*
* @defgroup lavc_encoding Encoding
* @{
* @}
*
* @defgroup lavc_codec Codecs
* @{
* @defgroup lavc_codec_native Native Codecs
* @{
* @}
* @defgroup lavc_codec_wrappers External library wrappers
* @{
* @}
* @defgroup lavc_codec_hwaccel Hardware Accelerators bridge
* @{
* @}
* @}
* @defgroup lavc_internal Internal
* @{
* @}
* @}
*
*/

/**
* @defgroup lavc_core Core functions/structures.
* @ingroup libavc
*
* Basic definitions, functions for querying libavcodec capabilities,
* allocating core structures, etc.
* @{
*/


/**
* Identify the syntax and semantics of the bitstream.
* The principle is roughly:
* Two decoders with the same ID can decode the same streams.
* Two encoders with the same ID can encode compatible streams.
* There may be slight deviations from the principle due to implementation
* details.
*
* If you add a codec ID to this list, add it so that
* 1. no value of a existing codec ID changes (that would break ABI),
* 2. it is as close as possible to similar codecs.
*
* After adding new codec IDs, do not forget to add an entry to the codec
* descriptor list and bump libavcodec minor version.
*/
enum AVCodecID {
   AV_CODEC_ID_NONE,

   /* video codecs */
   AV_CODEC_ID_MPEG1VIDEO,
   AV_CODEC_ID_MPEG2VIDEO, ///< preferred ID for MPEG-1/2 video decoding
#if FF_API_XVMC
   AV_CODEC_ID_MPEG2VIDEO_XVMC,
#endif /* FF_API_XVMC */
   AV_CODEC_ID_H261,
   AV_CODEC_ID_H263,
   AV_CODEC_ID_RV10,
   AV_CODEC_ID_RV20,
   AV_CODEC_ID_MJPEG,
   AV_CODEC_ID_MJPEGB,
   AV_CODEC_ID_LJPEG,
   AV_CODEC_ID_SP5X,
   AV_CODEC_ID_JPEGLS,
   AV_CODEC_ID_MPEG4,
   AV_CODEC_ID_RAWVIDEO,
   AV_CODEC_ID_MSMPEG4V1,
   AV_CODEC_ID_MSMPEG4V2,
   AV_CODEC_ID_MSMPEG4V3,
   AV_CODEC_ID_WMV1,
   AV_CODEC_ID_WMV2,
   AV_CODEC_ID_H263P,
   AV_CODEC_ID_H263I,
   AV_CODEC_ID_FLV1,
   AV_CODEC_ID_SVQ1,
   AV_CODEC_ID_SVQ3,
   AV_CODEC_ID_DVVIDEO,
   AV_CODEC_ID_HUFFYUV,
   AV_CODEC_ID_CYUV,
   AV_CODEC_ID_H264,
   AV_CODEC_ID_INDEO3,
   AV_CODEC_ID_VP3,
   AV_CODEC_ID_THEORA,
   AV_CODEC_ID_ASV1,
   AV_CODEC_ID_ASV2,
   AV_CODEC_ID_FFV1,
   AV_CODEC_ID_4XM,
   AV_CODEC_ID_VCR1,
   AV_CODEC_ID_CLJR,
   AV_CODEC_ID_MDEC,
   AV_CODEC_ID_ROQ,
   AV_CODEC_ID_INTERPLAY_VIDEO,
   AV_CODEC_ID_XAN_WC3,
   AV_CODEC_ID_XAN_WC4,
   AV_CODEC_ID_RPZA,
   AV_CODEC_ID_CINEPAK,
   AV_CODEC_ID_WS_VQA,
   AV_CODEC_ID_MSRLE,
   AV_CODEC_ID_MSVIDEO1,
   AV_CODEC_ID_IDCIN,
   AV_CODEC_ID_8BPS,
   AV_CODEC_ID_SMC,
   AV_CODEC_ID_FLIC,
   AV_CODEC_ID_TRUEMOTION1,
   AV_CODEC_ID_VMDVIDEO,
   AV_CODEC_ID_MSZH,
   AV_CODEC_ID_ZLIB,
   AV_CODEC_ID_QTRLE,
   AV_CODEC_ID_TSCC,
   AV_CODEC_ID_ULTI,
   AV_CODEC_ID_QDRAW,
   AV_CODEC_ID_VIXL,
   AV_CODEC_ID_QPEG,
   AV_CODEC_ID_PNG,
   AV_CODEC_ID_PPM,
   AV_CODEC_ID_PBM,
   AV_CODEC_ID_PGM,
   AV_CODEC_ID_PGMYUV,
   AV_CODEC_ID_PAM,
   AV_CODEC_ID_FFVHUFF,
   AV_CODEC_ID_RV30,
   AV_CODEC_ID_RV40,
   AV_CODEC_ID_VC1,
   AV_CODEC_ID_WMV3,
   AV_CODEC_ID_LOCO,
   AV_CODEC_ID_WNV1,
   AV_CODEC_ID_AASC,
   AV_CODEC_ID_INDEO2,
   AV_CODEC_ID_FRAPS,
   AV_CODEC_ID_TRUEMOTION2,
   AV_CODEC_ID_BMP,
   AV_CODEC_ID_CSCD,
   AV_CODEC_ID_MMVIDEO,
   AV_CODEC_ID_ZMBV,
   AV_CODEC_ID_AVS,
   AV_CODEC_ID_SMACKVIDEO,
   AV_CODEC_ID_NUV,
   AV_CODEC_ID_KMVC,
   AV_CODEC_ID_FLASHSV,
   AV_CODEC_ID_CAVS,
   AV_CODEC_ID_JPEG2000,
   AV_CODEC_ID_VMNC,
   AV_CODEC_ID_VP5,
   AV_CODEC_ID_VP6,
   AV_CODEC_ID_VP6F,
   AV_CODEC_ID_TARGA,
   AV_CODEC_ID_DSICINVIDEO,
   AV_CODEC_ID_TIERTEXSEQVIDEO,
   AV_CODEC_ID_TIFF,
   AV_CODEC_ID_GIF,
   AV_CODEC_ID_DXA,
   AV_CODEC_ID_DNXHD,
   AV_CODEC_ID_THP,
   AV_CODEC_ID_SGI,
   AV_CODEC_ID_C93,
   AV_CODEC_ID_BETHSOFTVID,
   AV_CODEC_ID_PTX,
   AV_CODEC_ID_TXD,
   AV_CODEC_ID_VP6A,
   AV_CODEC_ID_AMV,
   AV_CODEC_ID_VB,
   AV_CODEC_ID_PCX,
   AV_CODEC_ID_SUNRAST,
   AV_CODEC_ID_INDEO4,
   AV_CODEC_ID_INDEO5,
   AV_CODEC_ID_MIMIC,
   AV_CODEC_ID_RL2,
   AV_CODEC_ID_ESCAPE124,
   AV_CODEC_ID_DIRAC,
   AV_CODEC_ID_BFI,
   AV_CODEC_ID_CMV,
   AV_CODEC_ID_MOTIONPIXELS,
   AV_CODEC_ID_TGV,
   AV_CODEC_ID_TGQ,
   AV_CODEC_ID_TQI,
   AV_CODEC_ID_AURA,
   AV_CODEC_ID_AURA2,
   AV_CODEC_ID_V210X,
   AV_CODEC_ID_TMV,
   AV_CODEC_ID_V210,
   AV_CODEC_ID_DPX,
   AV_CODEC_ID_MAD,
   AV_CODEC_ID_FRWU,
   AV_CODEC_ID_FLASHSV2,
   AV_CODEC_ID_CDGRAPHICS,
   AV_CODEC_ID_R210,
   AV_CODEC_ID_ANM,
   AV_CODEC_ID_BINKVIDEO,
   AV_CODEC_ID_IFF_ILBM,
   AV_CODEC_ID_IFF_BYTERUN1,
   AV_CODEC_ID_KGV1,
   AV_CODEC_ID_YOP,
   AV_CODEC_ID_VP8,
   AV_CODEC_ID_PICTOR,
   AV_CODEC_ID_ANSI,
   AV_CODEC_ID_A64_MULTI,
   AV_CODEC_ID_A64_MULTI5,
   AV_CODEC_ID_R10K,
   AV_CODEC_ID_MXPEG,
   AV_CODEC_ID_LAGARITH,
   AV_CODEC_ID_PRORES,
   AV_CODEC_ID_JV,
   AV_CODEC_ID_DFA,
   AV_CODEC_ID_WMV3IMAGE,
   AV_CODEC_ID_VC1IMAGE,
   AV_CODEC_ID_UTVIDEO,
   AV_CODEC_ID_BMV_VIDEO,
   AV_CODEC_ID_VBLE,
   AV_CODEC_ID_DXTORY,
   AV_CODEC_ID_V410,
   AV_CODEC_ID_XWD,
   AV_CODEC_ID_CDXL,
   AV_CODEC_ID_XBM,
   AV_CODEC_ID_ZEROCODEC,
   AV_CODEC_ID_MSS1,
   AV_CODEC_ID_MSA1,
   AV_CODEC_ID_TSCC2,
   AV_CODEC_ID_MTS2,
   AV_CODEC_ID_CLLC,
   AV_CODEC_ID_MSS2,
   AV_CODEC_ID_VP9,
   AV_CODEC_ID_AIC,
   AV_CODEC_ID_ESCAPE130,
   AV_CODEC_ID_G2M,
   AV_CODEC_ID_WEBP,
   AV_CODEC_ID_HNM4_VIDEO,
   AV_CODEC_ID_HEVC,
   AV_CODEC_ID_FIC,

   /* various PCM "codecs" */
   AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs
   AV_CODEC_ID_PCM_S16LE = 0x10000,
   AV_CODEC_ID_PCM_S16BE,
   AV_CODEC_ID_PCM_U16LE,
   AV_CODEC_ID_PCM_U16BE,
   AV_CODEC_ID_PCM_S8,
   AV_CODEC_ID_PCM_U8,
   AV_CODEC_ID_PCM_MULAW,
   AV_CODEC_ID_PCM_ALAW,
   AV_CODEC_ID_PCM_S32LE,
   AV_CODEC_ID_PCM_S32BE,
   AV_CODEC_ID_PCM_U32LE,
   AV_CODEC_ID_PCM_U32BE,
   AV_CODEC_ID_PCM_S24LE,
   AV_CODEC_ID_PCM_S24BE,
   AV_CODEC_ID_PCM_U24LE,
   AV_CODEC_ID_PCM_U24BE,
   AV_CODEC_ID_PCM_S24DAUD,
   AV_CODEC_ID_PCM_ZORK,
   AV_CODEC_ID_PCM_S16LE_PLANAR,
   AV_CODEC_ID_PCM_DVD,
   AV_CODEC_ID_PCM_F32BE,
   AV_CODEC_ID_PCM_F32LE,
   AV_CODEC_ID_PCM_F64BE,
   AV_CODEC_ID_PCM_F64LE,
   AV_CODEC_ID_PCM_BLURAY,
   AV_CODEC_ID_PCM_LXF,
   AV_CODEC_ID_S302M,
   AV_CODEC_ID_PCM_S8_PLANAR,
   AV_CODEC_ID_PCM_S24LE_PLANAR,
   AV_CODEC_ID_PCM_S32LE_PLANAR,

   /* various ADPCM codecs */
   AV_CODEC_ID_ADPCM_IMA_QT = 0x11000,
   AV_CODEC_ID_ADPCM_IMA_WAV,
   AV_CODEC_ID_ADPCM_IMA_DK3,
   AV_CODEC_ID_ADPCM_IMA_DK4,
   AV_CODEC_ID_ADPCM_IMA_WS,
   AV_CODEC_ID_ADPCM_IMA_SMJPEG,
   AV_CODEC_ID_ADPCM_MS,
   AV_CODEC_ID_ADPCM_4XM,
   AV_CODEC_ID_ADPCM_XA,
   AV_CODEC_ID_ADPCM_ADX,
   AV_CODEC_ID_ADPCM_EA,
   AV_CODEC_ID_ADPCM_G726,
   AV_CODEC_ID_ADPCM_CT,
   AV_CODEC_ID_ADPCM_SWF,
   AV_CODEC_ID_ADPCM_YAMAHA,
   AV_CODEC_ID_ADPCM_SBPRO_4,
   AV_CODEC_ID_ADPCM_SBPRO_3,
   AV_CODEC_ID_ADPCM_SBPRO_2,
   AV_CODEC_ID_ADPCM_THP,
   AV_CODEC_ID_ADPCM_IMA_AMV,
   AV_CODEC_ID_ADPCM_EA_R1,
   AV_CODEC_ID_ADPCM_EA_R3,
   AV_CODEC_ID_ADPCM_EA_R2,
   AV_CODEC_ID_ADPCM_IMA_EA_SEAD,
   AV_CODEC_ID_ADPCM_IMA_EA_EACS,
   AV_CODEC_ID_ADPCM_EA_XAS,
   AV_CODEC_ID_ADPCM_EA_MAXIS_XA,
   AV_CODEC_ID_ADPCM_IMA_ISS,
   AV_CODEC_ID_ADPCM_G722,
   AV_CODEC_ID_ADPCM_IMA_APC,

   /* AMR */
   AV_CODEC_ID_AMR_NB = 0x12000,
   AV_CODEC_ID_AMR_WB,

   /* RealAudio codecs*/
   AV_CODEC_ID_RA_144 = 0x13000,
   AV_CODEC_ID_RA_288,

   /* various DPCM codecs */
   AV_CODEC_ID_ROQ_DPCM = 0x14000,
   AV_CODEC_ID_INTERPLAY_DPCM,
   AV_CODEC_ID_XAN_DPCM,
   AV_CODEC_ID_SOL_DPCM,

   /* audio codecs */
   AV_CODEC_ID_MP2 = 0x15000,
   AV_CODEC_ID_MP3, ///< preferred ID for decoding MPEG audio layer 1, 2 or 3
   AV_CODEC_ID_AAC,
   AV_CODEC_ID_AC3,
   AV_CODEC_ID_DTS,
   AV_CODEC_ID_VORBIS,
   AV_CODEC_ID_DVAUDIO,
   AV_CODEC_ID_WMAV1,
   AV_CODEC_ID_WMAV2,
   AV_CODEC_ID_MACE3,
   AV_CODEC_ID_MACE6,
   AV_CODEC_ID_VMDAUDIO,
   AV_CODEC_ID_FLAC,
   AV_CODEC_ID_MP3ADU,
   AV_CODEC_ID_MP3ON4,
   AV_CODEC_ID_SHORTEN,
   AV_CODEC_ID_ALAC,
   AV_CODEC_ID_WESTWOOD_SND1,
   AV_CODEC_ID_GSM, ///< as in Berlin toast format
   AV_CODEC_ID_QDM2,
   AV_CODEC_ID_COOK,
   AV_CODEC_ID_TRUESPEECH,
   AV_CODEC_ID_TTA,
   AV_CODEC_ID_SMACKAUDIO,
   AV_CODEC_ID_QCELP,
   AV_CODEC_ID_WAVPACK,
   AV_CODEC_ID_DSICINAUDIO,
   AV_CODEC_ID_IMC,
   AV_CODEC_ID_MUSEPACK7,
   AV_CODEC_ID_MLP,
   AV_CODEC_ID_GSM_MS, /* as found in WAV */
   AV_CODEC_ID_ATRAC3,
#if FF_API_VOXWARE
   AV_CODEC_ID_VOXWARE,
#endif
   AV_CODEC_ID_APE,
   AV_CODEC_ID_NELLYMOSER,
   AV_CODEC_ID_MUSEPACK8,
   AV_CODEC_ID_SPEEX,
   AV_CODEC_ID_WMAVOICE,
   AV_CODEC_ID_WMAPRO,
   AV_CODEC_ID_WMALOSSLESS,
   AV_CODEC_ID_ATRAC3P,
   AV_CODEC_ID_EAC3,
   AV_CODEC_ID_SIPR,
   AV_CODEC_ID_MP1,
   AV_CODEC_ID_TWINVQ,
   AV_CODEC_ID_TRUEHD,
   AV_CODEC_ID_MP4ALS,
   AV_CODEC_ID_ATRAC1,
   AV_CODEC_ID_BINKAUDIO_RDFT,
   AV_CODEC_ID_BINKAUDIO_DCT,
   AV_CODEC_ID_AAC_LATM,
   AV_CODEC_ID_QDMC,
   AV_CODEC_ID_CELT,
   AV_CODEC_ID_G723_1,
   AV_CODEC_ID_G729,
   AV_CODEC_ID_8SVX_EXP,
   AV_CODEC_ID_8SVX_FIB,
   AV_CODEC_ID_BMV_AUDIO,
   AV_CODEC_ID_RALF,
   AV_CODEC_ID_IAC,
   AV_CODEC_ID_ILBC,
   AV_CODEC_ID_OPUS,
   AV_CODEC_ID_COMFORT_NOISE,
   AV_CODEC_ID_TAK,
   AV_CODEC_ID_METASOUND,

   /* subtitle codecs */
   AV_CODEC_ID_FIRST_SUBTITLE = 0x17000,          ///< A dummy ID pointing at the start of subtitle codecs.
   AV_CODEC_ID_DVD_SUBTITLE = 0x17000,
   AV_CODEC_ID_DVB_SUBTITLE,
   AV_CODEC_ID_TEXT,  ///< raw UTF-8 text
   AV_CODEC_ID_XSUB,
   AV_CODEC_ID_SSA,
   AV_CODEC_ID_MOV_TEXT,
   AV_CODEC_ID_HDMV_PGS_SUBTITLE,
   AV_CODEC_ID_DVB_TELETEXT,
   AV_CODEC_ID_SRT,

   /* other specific kind of codecs (generally used for attachments) */
   AV_CODEC_ID_FIRST_UNKNOWN = 0x18000,           ///< A dummy ID pointing at the start of various fake codecs.
   AV_CODEC_ID_TTF = 0x18000,

   AV_CODEC_ID_PROBE = 0x19000, ///< codec_id is not known (like AV_CODEC_ID_NONE) but lavf should attempt to identify it

   AV_CODEC_ID_MPEG2TS = 0x20000, /**< _FAKE_ codec to indicate a raw MPEG-2 TS
                               * stream (only used by libavformat) */
   AV_CODEC_ID_MPEG4SYSTEMS = 0x20001, /**< _FAKE_ codec to indicate a MPEG-4 Systems
                               * stream (only used by libavformat) */
   AV_CODEC_ID_FFMETADATA = 0x21000,   ///< Dummy codec for streams containing only metadata information.
};

/**
* This struct describes the properties of a single codec described by an
* AVCodecID.
* @see avcodec_get_descriptor()
*/
typedef struct AVCodecDescriptor {
   enum AVCodecID     id;
   enum AVMediaType type;
   /**
    * Name of the codec described by this descriptor. It is non-empty and
    * unique for each codec descriptor. It should contain alphanumeric
    * characters and '_' only.
    */
   const char      *name;
   /**
    * A more descriptive name for this codec. May be NULL.
    */
   const char *long_name;
   /**
    * Codec properties, a combination of AV_CODEC_PROP_* flags.
    */
   int             props;
} AVCodecDescriptor;

/**
* Codec uses only intra compression.
* Video codecs only.
*/
#define AV_CODEC_PROP_INTRA_ONLY    (1 << 0)
/**
* Codec supports lossy compression. Audio and video codecs only.
* @note a codec may support both lossy and lossless
* compression modes
*/
#define AV_CODEC_PROP_LOSSY         (1 << 1)
/**
* Codec supports lossless compression. Audio and video codecs only.
*/
#define AV_CODEC_PROP_LOSSLESS      (1 << 2)

/**
* @ingroup lavc_decoding
* Required number of additionally allocated bytes at the end of the input bitstream for decoding.
* This is mainly needed because some optimized bitstream readers read
* 32 or 64 bit at once and could read over the end.<br>
* Note: If the first 23 bits of the additional bytes are not 0, then damaged
* MPEG bitstreams could cause overread and segfault.
*/
#define FF_INPUT_BUFFER_PADDING_SIZE 8

/**
* @ingroup lavc_encoding
* minimum encoding buffer size
* Used to avoid some checks during header writing.
*/
#define FF_MIN_BUFFER_SIZE 16384


/**
* @ingroup lavc_encoding
* motion estimation type.
*/
enum Motion_Est_ID {
   ME_ZERO = 1,    ///< no search, that is use 0,0 vector whenever one is needed
   ME_FULL,
   ME_LOG,
   ME_PHODS,
   ME_EPZS,        ///< enhanced predictive zonal search
   ME_X1,          ///< reserved for experiments
   ME_HEX,         ///< hexagon based search
   ME_UMH,         ///< uneven multi-hexagon search
   ME_TESA,        ///< transformed exhaustive search algorithm
};

/**
* @ingroup lavc_decoding
*/
enum AVDiscard{
   /* We leave some space between them for extensions (drop some
    * keyframes for intra-only or drop just some bidir frames). */
   AVDISCARD_NONE    =-16, ///< discard nothing
   AVDISCARD_DEFAULT =  0, ///< discard useless packets like 0 size packets in avi
   AVDISCARD_NONREF  =  8, ///< discard all non reference
   AVDISCARD_BIDIR   = 16, ///< discard all bidirectional frames
   AVDISCARD_NONKEY  = 32, ///< discard all frames except keyframes
   AVDISCARD_ALL     = 48, ///< discard all
};

enum AVColorPrimaries{
   AVCOL_PRI_BT709       = 1, ///< also ITU-R BT1361 / IEC 61966-2-4 / SMPTE RP177 Annex B
   AVCOL_PRI_UNSPECIFIED = 2,
   AVCOL_PRI_BT470M      = 4,
   AVCOL_PRI_BT470BG     = 5, ///< also ITU-R BT601-6 625 / ITU-R BT1358 625 / ITU-R BT1700 625 PAL & SECAM
   AVCOL_PRI_SMPTE170M   = 6, ///< also ITU-R BT601-6 525 / ITU-R BT1358 525 / ITU-R BT1700 NTSC
   AVCOL_PRI_SMPTE240M   = 7, ///< functionally identical to above
   AVCOL_PRI_FILM        = 8,
   AVCOL_PRI_BT2020      = 9, ///< ITU-R BT2020
   AVCOL_PRI_NB             , ///< Not part of ABI
};

enum AVColorTransferCharacteristic{
   AVCOL_TRC_BT709        =  1, ///< also ITU-R BT1361
   AVCOL_TRC_UNSPECIFIED  =  2,
   AVCOL_TRC_GAMMA22      =  4, ///< also ITU-R BT470M / ITU-R BT1700 625 PAL & SECAM
   AVCOL_TRC_GAMMA28      =  5, ///< also ITU-R BT470BG
   AVCOL_TRC_SMPTE170M    =  6, ///< also ITU-R BT601-6 525 or 625 / ITU-R BT1358 525 or 625 / ITU-R BT1700 NTSC
   AVCOL_TRC_SMPTE240M    =  7,
   AVCOL_TRC_LINEAR       =  8, ///< "Linear transfer characteristics"
   AVCOL_TRC_LOG          =  9, ///< "Logarithmic transfer characteristic (100:1 range)"
   AVCOL_TRC_LOG_SQRT     = 10, ///< "Logarithmic transfer characteristic (100 * Sqrt( 10 ) : 1 range)"
   AVCOL_TRC_IEC61966_2_4 = 11, ///< IEC 61966-2-4
   AVCOL_TRC_BT1361_ECG   = 12, ///< ITU-R BT1361 Extended Colour Gamut
   AVCOL_TRC_IEC61966_2_1 = 13, ///< IEC 61966-2-1 (sRGB or sYCC)
   AVCOL_TRC_BT2020_10    = 14, ///< ITU-R BT2020 for 10 bit system
   AVCOL_TRC_BT2020_12    = 15, ///< ITU-R BT2020 for 12 bit system
   AVCOL_TRC_NB               , ///< Not part of ABI
};

enum AVColorSpace{
   AVCOL_SPC_RGB         =  0,
   AVCOL_SPC_BT709       =  1, ///< also ITU-R BT1361 / IEC 61966-2-4 xvYCC709 / SMPTE RP177 Annex B
   AVCOL_SPC_UNSPECIFIED =  2,
   AVCOL_SPC_FCC         =  4,
   AVCOL_SPC_BT470BG     =  5, ///< also ITU-R BT601-6 625 / ITU-R BT1358 625 / ITU-R BT1700 625 PAL & SECAM / IEC 61966-2-4 xvYCC601
   AVCOL_SPC_SMPTE170M   =  6, ///< also ITU-R BT601-6 525 / ITU-R BT1358 525 / ITU-R BT1700 NTSC / functionally identical to above
   AVCOL_SPC_SMPTE240M   =  7,
   AVCOL_SPC_YCOCG       =  8, ///< Used by Dirac / VC-2 and H.264 FRext, see ITU-T SG16
   AVCOL_SPC_BT2020_NCL  =  9, ///< ITU-R BT2020 non-constant luminance system
   AVCOL_SPC_BT2020_CL   = 10, ///< ITU-R BT2020 constant luminance system
   AVCOL_SPC_NB              , ///< Not part of ABI
};

enum AVColorRange{
   AVCOL_RANGE_UNSPECIFIED = 0,
   AVCOL_RANGE_MPEG        = 1, ///< the normal 219*2^(n-8) "MPEG" YUV ranges
   AVCOL_RANGE_JPEG        = 2, ///< the normal     2^n-1   "JPEG" YUV ranges
   AVCOL_RANGE_NB             , ///< Not part of ABI
};

/**
*  X   X      3 4 X      X are luma samples,
*             1 2        1-6 are possible chroma positions
*  X   X      5 6 X      0 is undefined/unknown position
*/
enum AVChromaLocation{
   AVCHROMA_LOC_UNSPECIFIED = 0,
   AVCHROMA_LOC_LEFT        = 1, ///< mpeg2/4, h264 default
   AVCHROMA_LOC_CENTER      = 2, ///< mpeg1, jpeg, h263
   AVCHROMA_LOC_TOPLEFT     = 3, ///< DV
   AVCHROMA_LOC_TOP         = 4,
   AVCHROMA_LOC_BOTTOMLEFT  = 5,
   AVCHROMA_LOC_BOTTOM      = 6,
   AVCHROMA_LOC_NB             , ///< Not part of ABI
};

enum AVAudioServiceType {
   AV_AUDIO_SERVICE_TYPE_MAIN              = 0,
   AV_AUDIO_SERVICE_TYPE_EFFECTS           = 1,
   AV_AUDIO_SERVICE_TYPE_VISUALLY_IMPAIRED = 2,
   AV_AUDIO_SERVICE_TYPE_HEARING_IMPAIRED  = 3,
   AV_AUDIO_SERVICE_TYPE_DIALOGUE          = 4,
   AV_AUDIO_SERVICE_TYPE_COMMENTARY        = 5,
   AV_AUDIO_SERVICE_TYPE_EMERGENCY         = 6,
   AV_AUDIO_SERVICE_TYPE_VOICE_OVER        = 7,
   AV_AUDIO_SERVICE_TYPE_KARAOKE           = 8,
   AV_AUDIO_SERVICE_TYPE_NB                   , ///< Not part of ABI
};

/**
* @ingroup lavc_encoding
*/
typedef struct RcOverride{
   int start_frame;
   int end_frame;
   int qscale; // If this is 0 then quality_factor will be used instead.
   float quality_factor;
} RcOverride;

#if FF_API_MAX_BFRAMES
/**
* @deprecated there is no libavcodec-wide limit on the number of B-frames
*/
#define FF_MAX_B_FRAMES 16
#endif

/* encoding support
  These flags can be passed in AVCodecContext.flags before initialization.
  Note: Not everything is supported yet.
*/

/**
* Allow decoders to produce frames with data planes that are not aligned
* to CPU requirements (e.g. due to cropping).
*/
#define CODEC_FLAG_UNALIGNED 0x0001
#define CODEC_FLAG_QSCALE 0x0002  ///< Use fixed qscale.
#define CODEC_FLAG_4MV    0x0004  ///< 4 MV per MB allowed / advanced prediction for H.263.
#define CODEC_FLAG_OUTPUT_CORRUPT 0x0008 ///< Output even those frames that might be corrupted
#define CODEC_FLAG_QPEL   0x0010  ///< Use qpel MC.
#define CODEC_FLAG_GMC    0x0020  ///< Use GMC.
#define CODEC_FLAG_MV0    0x0040  ///< Always try a MB with MV=<0,0>.
/**
* The parent program guarantees that the input for B-frames containing
* streams is not written to for at least s->max_b_frames+1 frames, if
* this is not set the input will be copied.
*/
#define CODEC_FLAG_INPUT_PRESERVED 0x0100
#define CODEC_FLAG_PASS1           0x0200   ///< Use internal 2pass ratecontrol in first pass mode.
#define CODEC_FLAG_PASS2           0x0400   ///< Use internal 2pass ratecontrol in second pass mode.
#define CODEC_FLAG_GRAY            0x2000   ///< Only decode/encode grayscale.
#if FF_API_EMU_EDGE
/**
* @deprecated edges are not used/required anymore. I.e. this flag is now always
* set.
*/
#define CODEC_FLAG_EMU_EDGE        0x4000
#endif
#define CODEC_FLAG_PSNR            0x8000   ///< error[?] variables will be set during encoding.
#define CODEC_FLAG_TRUNCATED       0x00010000 /** Input bitstream might be truncated at a random
                                                 location instead of only at frame boundaries. */
#define CODEC_FLAG_NORMALIZE_AQP  0x00020000 ///< Normalize adaptive quantization.
#define CODEC_FLAG_INTERLACED_DCT 0x00040000 ///< Use interlaced DCT.
#define CODEC_FLAG_LOW_DELAY      0x00080000 ///< Force low delay.
#define CODEC_FLAG_GLOBAL_HEADER  0x00400000 ///< Place global headers in extradata instead of every keyframe.
#define CODEC_FLAG_BITEXACT       0x00800000 ///< Use only bitexact stuff (except (I)DCT).
/* Fx : Flag for h263+ extra options */
#define CODEC_FLAG_AC_PRED        0x01000000 ///< H.263 advanced intra coding / MPEG-4 AC prediction
#define CODEC_FLAG_LOOP_FILTER    0x00000800 ///< loop filter
#define CODEC_FLAG_INTERLACED_ME  0x20000000 ///< interlaced motion estimation
#define CODEC_FLAG_CLOSED_GOP     0x80000000
#define CODEC_FLAG2_FAST          0x00000001 ///< Allow non spec compliant speedup tricks.
#define CODEC_FLAG2_NO_OUTPUT     0x00000004 ///< Skip bitstream encoding.
#define CODEC_FLAG2_LOCAL_HEADER  0x00000008 ///< Place global headers at every keyframe instead of in extradata.
#define CODEC_FLAG2_IGNORE_CROP   0x00010000 ///< Discard cropping information from SPS.

#define CODEC_FLAG2_CHUNKS        0x00008000 ///< Input bitstream might be truncated at a packet boundaries instead of only at frame boundaries.

/* Unsupported options :
*              Syntax Arithmetic coding (SAC)
*              Reference Picture Selection
*              Independent Segment Decoding */
/* /Fx */
/* codec capabilities */

#define CODEC_CAP_DRAW_HORIZ_BAND 0x0001 ///< Decoder can use draw_horiz_band callback.
/**
* Codec uses get_buffer() for allocating buffers and supports custom allocators.
* If not set, it might not use get_buffer() at all or use operations that
* assume the buffer was allocated by avcodec_default_get_buffer.
*/
#define CODEC_CAP_DR1             0x0002
#define CODEC_CAP_TRUNCATED       0x0008
#if FF_API_XVMC
/* Codec can export data for HW decoding (XvMC). */
#define CODEC_CAP_HWACCEL         0x0010
#endif /* FF_API_XVMC */
/**
* Encoder or decoder requires flushing with NULL input at the end in order to
* give the complete and correct output.
*
* NOTE: If this flag is not set, the codec is guaranteed to never be fed with
*       with NULL data. The user can still send NULL data to the public encode
*       or decode function, but libavcodec will not pass it along to the codec
*       unless this flag is set.
*
* Decoders:
* The decoder has a non-zero delay and needs to be fed with avpkt->data=NULL,
* avpkt->size=0 at the end to get the delayed data until the decoder no longer
* returns frames.
*
* Encoders:
* The encoder needs to be fed with NULL data at the end of encoding until the
* encoder no longer returns data.
*
* NOTE: For encoders implementing the AVCodec.encode2() function, setting this
*       flag also means that the encoder must set the pts and duration for
*       each output packet. If this flag is not set, the pts and duration will
*       be determined by libavcodec from the input frame.
*/
#define CODEC_CAP_DELAY           0x0020
/**
* Codec can be fed a final frame with a smaller size.
* This can be used to prevent truncation of the last audio samples.
*/
#define CODEC_CAP_SMALL_LAST_FRAME 0x0040
#if FF_API_CAP_VDPAU
/**
* Codec can export data for HW decoding (VDPAU).
*/
#define CODEC_CAP_HWACCEL_VDPAU    0x0080
#endif
/**
* Codec can output multiple frames per AVPacket
* Normally demuxers return one frame at a time, demuxers which do not do
* are connected to a parser to split what they return into proper frames.
* This flag is reserved to the very rare category of codecs which have a
* bitstream that cannot be split into frames without timeconsuming
* operations like full decoding. Demuxers carring such bitstreams thus
* may return multiple frames in a packet. This has many disadvantages like
* prohibiting stream copy in many cases thus it should only be considered
* as a last resort.
*/
#define CODEC_CAP_SUBFRAMES        0x0100
/**
* Codec is experimental and is thus avoided in favor of non experimental
* encoders
*/
#define CODEC_CAP_EXPERIMENTAL     0x0200
/**
* Codec should fill in channel configuration and samplerate instead of container
*/
#define CODEC_CAP_CHANNEL_CONF     0x0400
#if FF_API_NEG_LINESIZES
/**
* @deprecated no codecs use this capability
*/
#define CODEC_CAP_NEG_LINESIZES    0x0800
#endif
/**
* Codec supports frame-level multithreading.
*/
#define CODEC_CAP_FRAME_THREADS    0x1000
/**
* Codec supports slice-based (or partition-based) multithreading.
*/
#define CODEC_CAP_SLICE_THREADS    0x2000
/**
* Codec supports changed parameters at any point.
*/
#define CODEC_CAP_PARAM_CHANGE     0x4000
/**
* Codec supports avctx->thread_count == 0 (auto).
*/
#define CODEC_CAP_AUTO_THREADS     0x8000
/**
* Audio encoder supports receiving a different number of samples in each call.
*/
#define CODEC_CAP_VARIABLE_FRAME_SIZE 0x10000

#if FF_API_MB_TYPE
//The following defines may change, don't expect compatibility if you use them.
#define MB_TYPE_INTRA4x4   0x0001
#define MB_TYPE_INTRA16x16 0x0002 //FIXME H.264-specific
#define MB_TYPE_INTRA_PCM  0x0004 //FIXME H.264-specific
#define MB_TYPE_16x16      0x0008
#define MB_TYPE_16x8       0x0010
#define MB_TYPE_8x16       0x0020
#define MB_TYPE_8x8        0x0040
#define MB_TYPE_INTERLACED 0x0080
#define MB_TYPE_DIRECT2    0x0100 //FIXME
#define MB_TYPE_ACPRED     0x0200
#define MB_TYPE_GMC        0x0400
#define MB_TYPE_SKIP       0x0800
#define MB_TYPE_P0L0       0x1000
#define MB_TYPE_P1L0       0x2000
#define MB_TYPE_P0L1       0x4000
#define MB_TYPE_P1L1       0x8000
#define MB_TYPE_L0         (MB_TYPE_P0L0 | MB_TYPE_P1L0)
#define MB_TYPE_L1         (MB_TYPE_P0L1 | MB_TYPE_P1L1)
#define MB_TYPE_L0L1       (MB_TYPE_L0   | MB_TYPE_L1)
#define MB_TYPE_QUANT      0x00010000
#define MB_TYPE_CBP        0x00020000
//Note bits 24-31 are reserved for codec specific use (h264 ref0, mpeg1 0mv, ...)
#endif

/**
* Pan Scan area.
* This specifies the area which should be displayed.
* Note there may be multiple such areas for one frame.
*/
typedef struct AVPanScan{
   /**
    * id
    * - encoding: Set by user.
    * - decoding: Set by libavcodec.
    */
   int id;

   /**
    * width and height in 1/16 pel
    * - encoding: Set by user.
    * - decoding: Set by libavcodec.
    */
   int width;
   int height;

   /**
    * position of the top left corner in 1/16 pel for up to 3 fields/frames
    * - encoding: Set by user.
    * - decoding: Set by libavcodec.
    */
   int16_t position[3][2];
}AVPanScan;

#if FF_API_QSCALE_TYPE
#define FF_QSCALE_TYPE_MPEG1 0
#define FF_QSCALE_TYPE_MPEG2 1
#define FF_QSCALE_TYPE_H264  2
#define FF_QSCALE_TYPE_VP56  3
#endif

#if FF_API_GET_BUFFER
#define FF_BUFFER_TYPE_INTERNAL 1
#define FF_BUFFER_TYPE_USER     2 ///< direct rendering buffers (image is (de)allocated by user)
#define FF_BUFFER_TYPE_SHARED   4 ///< Buffer from somewhere else; don't deallocate image (data/base), all other tables are not shared.
#define FF_BUFFER_TYPE_COPY     8 ///< Just a (modified) copy of some other buffer, don't deallocate anything.

#define FF_BUFFER_HINTS_VALID    0x01 // Buffer hints value is meaningful (if 0 ignore).
#define FF_BUFFER_HINTS_READABLE 0x02 // Codec will read from buffer.
#define FF_BUFFER_HINTS_PRESERVE 0x04 // User must not alter buffer content.
#define FF_BUFFER_HINTS_REUSABLE 0x08 // Codec will reuse the buffer (update).
#endif

/**
* The decoder will keep a reference to the frame and may reuse it later.
*/
#define AV_GET_BUFFER_FLAG_REF (1 << 0)

/**
* @defgroup lavc_packet AVPacket
*
* Types and functions for working with AVPacket.
* @{
*/
enum AVPacketSideDataType {
   AV_PKT_DATA_PALETTE,
   AV_PKT_DATA_NEW_EXTRADATA,

   /**
    * An AV_PKT_DATA_PARAM_CHANGE side data packet is laid out as follows:
    * @code
    * u32le param_flags
    * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT)
    *     s32le channel_count
    * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT)
    *     u64le channel_layout
    * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE)
    *     s32le sample_rate
    * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS)
    *     s32le width
    *     s32le height
    * @endcode
    */
   AV_PKT_DATA_PARAM_CHANGE,

   /**
    * An AV_PKT_DATA_H263_MB_INFO side data packet contains a number of
    * structures with info about macroblocks relevant to splitting the
    * packet into smaller packets on macroblock edges (e.g. as for RFC 2190).
    * That is, it does not necessarily contain info about all macroblocks,
    * as long as the distance between macroblocks in the info is smaller
    * than the target payload size.
    * Each MB info structure is 12 bytes, and is laid out as follows:
    * @code
    * u32le bit offset from the start of the packet
    * u8    current quantizer at the start of the macroblock
    * u8    GOB number
    * u16le macroblock address within the GOB
    * u8    horizontal MV predictor
    * u8    vertical MV predictor
    * u8    horizontal MV predictor for block number 3
    * u8    vertical MV predictor for block number 3
    * @endcode
    */
   AV_PKT_DATA_H263_MB_INFO,
};

/**
* This structure stores compressed data. It is typically exported by demuxers
* and then passed as input to decoders, or received as output from encoders and
* then passed to muxers.
*
* For video, it should typically contain one compressed frame. For audio it may
* contain several compressed frames.
*
* AVPacket is one of the few structs in Libav, whose size is a part of public
* ABI. Thus it may be allocated on stack and no new fields can be added to it
* without libavcodec and libavformat major bump.
*
* The semantics of data ownership depends on the buf or destruct (deprecated)
* fields. If either is set, the packet data is dynamically allocated and is
* valid indefinitely until av_free_packet() is called (which in turn calls
* av_buffer_unref()/the destruct callback to free the data). If neither is set,
* the packet data is typically backed by some static buffer somewhere and is
* only valid for a limited time (e.g. until the next read call when demuxing).
*
* The side data is always allocated with av_malloc() and is freed in
* av_free_packet().
*/
typedef struct AVPacket {
   /**
    * A reference to the reference-counted buffer where the packet data is
    * stored.
    * May be NULL, then the packet data is not reference-counted.
    */
   AVBufferRef *buf;
   /**
    * Presentation timestamp in AVStream->time_base units; the time at which
    * the decompressed packet will be presented to the user.
    * Can be AV_NOPTS_VALUE if it is not stored in the file.
    * pts MUST be larger or equal to dts as presentation cannot happen before
    * decompression, unless one wants to view hex dumps. Some formats misuse
    * the terms dts and pts/cts to mean something different. Such timestamps
    * must be converted to true pts/dts before they are stored in AVPacket.
    */
   int64_t pts;
   /**
    * Decompression timestamp in AVStream->time_base units; the time at which
    * the packet is decompressed.
    * Can be AV_NOPTS_VALUE if it is not stored in the file.
    */
   int64_t dts;
   uint8_t *data;
   int   size;
   int   stream_index;
   /**
    * A combination of AV_PKT_FLAG values
    */
   int   flags;
   /**
    * Additional packet data that can be provided by the container.
    * Packet can contain several types of side information.
    */
   struct {
       uint8_t *data;
       int      size;
       enum AVPacketSideDataType type;
   } *side_data;
   int side_data_elems;

   /**
    * Duration of this packet in AVStream->time_base units, 0 if unknown.
    * Equals next_pts - this_pts in presentation order.
    */
   int   duration;
#if FF_API_DESTRUCT_PACKET
   attribute_deprecated
   void  (*destruct)(struct AVPacket *);
   attribute_deprecated
   void  *priv;
#endif
   int64_t pos;                            ///< byte position in stream, -1 if unknown

   /**
    * Time difference in AVStream->time_base units from the pts of this
    * packet to the point at which the output from the decoder has converged
    * independent from the availability of previous frames. That is, the
    * frames are virtually identical no matter if decoding started from
    * the very first frame or from this keyframe.
    * Is AV_NOPTS_VALUE if unknown.
    * This field is not the display duration of the current packet.
    * This field has no meaning if the packet does not have AV_PKT_FLAG_KEY
    * set.
    *
    * The purpose of this field is to allow seeking in streams that have no
    * keyframes in the conventional sense. It corresponds to the
    * recovery point SEI in H.264 and match_time_delta in NUT. It is also
    * essential for some types of subtitle streams to ensure that all
    * subtitles are correctly displayed after seeking.
    */
   int64_t convergence_duration;
} AVPacket;
#define AV_PKT_FLAG_KEY     0x0001 ///< The packet contains a keyframe
#define AV_PKT_FLAG_CORRUPT 0x0002 ///< The packet content is corrupted

enum AVSideDataParamChangeFlags {
   AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT  = 0x0001,
   AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT = 0x0002,
   AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE    = 0x0004,
   AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS     = 0x0008,
};
/**
* @}
*/

struct AVCodecInternal;

enum AVFieldOrder {
   AV_FIELD_UNKNOWN,
   AV_FIELD_PROGRESSIVE,
   AV_FIELD_TT,          //< Top coded_first, top displayed first
   AV_FIELD_BB,          //< Bottom coded first, bottom displayed first
   AV_FIELD_TB,          //< Top coded first, bottom displayed first
   AV_FIELD_BT,          //< Bottom coded first, top displayed first
};

/**
* main external API structure.
* New fields can be added to the end with minor version bumps.
* Removal, reordering and changes to existing fields require a major
* version bump.
* sizeof(AVCodecContext) must not be used outside libav*.
*/
typedef struct AVCodecContext {
   /**
    * information on struct for av_log
    * - set by avcodec_alloc_context3
    */
   const AVClass *av_class;
   int log_level_offset;

   enum AVMediaType codec_type; /* see AVMEDIA_TYPE_xxx */
   const struct AVCodec  *codec;
   char             codec_name[32];
   enum AVCodecID     codec_id; /* see AV_CODEC_ID_xxx */

   /**
    * fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
    * This is used to work around some encoder bugs.
    * A demuxer should set this to what is stored in the field used to identify the codec.
    * If there are multiple such fields in a container then the demuxer should choose the one
    * which maximizes the information about the used codec.
    * If the codec tag field in a container is larger than 32 bits then the demuxer should
    * remap the longer ID to 32 bits with a table or other structure. Alternatively a new
    * extra_codec_tag + size could be added but for this a clear advantage must be demonstrated
    * first.
    * - encoding: Set by user, if not then the default based on codec_id will be used.
    * - decoding: Set by user, will be converted to uppercase by libavcodec during init.
    */
   unsigned int codec_tag;

   /**
    * fourcc from the AVI stream header (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
    * This is used to work around some encoder bugs.
    * - encoding: unused
    * - decoding: Set by user, will be converted to uppercase by libavcodec during init.
    */
   unsigned int stream_codec_tag;

   void *priv_data;

   /**
    * Private context used for internal data.
    *
    * Unlike priv_data, this is not codec-specific. It is used in general
    * libavcodec functions.
    */
   struct AVCodecInternal *internal;

   /**
    * Private data of the user, can be used to carry app specific stuff.
    * - encoding: Set by user.
    * - decoding: Set by user.
    */
   void *opaque;

   /**
    * the average bitrate
    * - encoding: Set by user; unused for constant quantizer encoding.
    * - decoding: Set by libavcodec. 0 or some bitrate if this info is available in the stream.
    */
   int bit_rate;

   /**
    * number of bits the bitstream is allowed to diverge from the reference.
    *           the reference can be CBR (for CBR pass1) or VBR (for pass2)
    * - encoding: Set by user; unused for constant quantizer encoding.
    * - decoding: unused
    */
   int bit_rate_tolerance;

   /**
    * Global quality for codecs which cannot change it per frame.
    * This should be proportional to MPEG-1/2/4 qscale.
    * - encoding: Set by user.
    * - decoding: unused
    */
   int global_quality;

   /**
    * - encoding: Set by user.
    * - decoding: unused
    */
   int compression_level;
#define FF_COMPRESSION_DEFAULT -1

   /**
    * CODEC_FLAG_*.
    * - encoding: Set by user.
    * - decoding: Set by user.
    */
   int flags;

   /**
    * CODEC_FLAG2_*
    * - encoding: Set by user.
    * - decoding: Set by user.
    */
   int flags2;

   /**
    * some codecs need / can use extradata like Huffman tables.
    * mjpeg: Huffman tables
    * rv10: additional flags
    * mpeg4: global headers (they can be in the bitstream or here)
    * The allocated memory should be FF_INPUT_BUFFER_PADDING_SIZE bytes larger
    * than extradata_size to avoid prolems if it is read with the bitstream reader.
    * The bytewise contents of extradata must not depend on the architecture or CPU endianness.
    * - encoding: Set/allocated/freed by libavcodec.
    * - decoding: Set/allocated/freed by user.
    */
   uint8_t *extradata;
   int extradata_size;

   /**
    * This is the fundamental unit of time (in seconds) in terms
    * of which frame timestamps are represented. For fixed-fps content,
    * timebase should be 1/framerate and timestamp increments should be
    * identically 1.
    * - encoding: MUST be set by user.
    * - decoding: Set by libavcodec.
    */
   AVRational time_base;

   /**
    * For some codecs, the time base is closer to the field rate than the frame rate.
    * Most notably, H.264 and MPEG-2 specify time_base as half of frame duration
    * if no telecine is used ...
    *
    * Set to time_base ticks per frame. Default 1, e.g., H.264/MPEG-2 set it to 2.
    */
   int ticks_per_frame;

   /**
    * Codec delay.
    *
    * Video:
    *   Number of frames the decoded output will be delayed relative to the
    *   encoded input.
    *
    * Audio:
    *   For encoding, this is the number of "priming" samples added to the
    *   beginning of the stream. The decoded output will be delayed by this
    *   many samples relative to the input to the encoder. Note that this
    *   field is purely informational and does not directly affect the pts
    *   output by the encoder, which should always be based on the actual
    *   presentation time, including any delay.
    *   For decoding, this is the number of samples the decoder needs to
    *   output before the decoder's output is valid. When seeking, you should
    *   start decoding this many samples prior to your desired seek point.
    *
    * - encoding: Set by libavcodec.
    * - decoding: Set by libavcodec.
    */
   int delay;


   /* video only */
   /**
    * picture width / height.
    * - encoding: MUST be set by user.
    * - decoding: May be set by the user before opening the decoder if known e.g.
    *             from the container. Some decoders will require the dimensions
    *             to be set by the caller. During decoding, the decoder may
    *             overwrite those values as required.
    */
   int width, height;

   /**
    * Bitstream width / height, may be different from width/height e.g. when
    * the decoded frame is cropped before being output.
    * - encoding: unused
    * - decoding: May be set by the user before opening the decoder if known
    *             e.g. from the container. During decoding, the decoder may
    *             overwrite those values as required.
    */
   int coded_width, coded_height;

#if FF_API_ASPECT_EXTENDED
#define FF_ASPECT_EXTENDED 15
#endif

   /**
    * the number of pictures in a group of pictures, or 0 for intra_only
    * - encoding: Set by user.
    * - decoding: unused
    */
   int gop_size;

   /**
    * Pixel format, see AV_PIX_FMT_xxx.
    * May be set by the demuxer if known from headers.
    * May be overriden by the decoder if it knows better.
    * - encoding: Set by user.
    * - decoding: Set by user if known, overridden by libavcodec if known
    */
   enum AVPixelFormat pix_fmt;

   /**
    * Motion estimation algorithm used for video coding.
    * 1 (zero), 2 (full), 3 (log), 4 (phods), 5 (epzs), 6 (x1), 7 (hex),
    * 8 (umh), 10 (tesa) [7, 8, 10 are x264 specific]
    * - encoding: MUST be set by user.
    * - decoding: unused
    */
   int me_method;

   /**
    * If non NULL, 'draw_horiz_band' is called by the libavcodec
    * decoder to draw a horizontal band. It improves cache usage. Not
    * all codecs can do that. You must check the codec capabilities
    * beforehand.
    * When multithreading is used, it may be called from multiple threads
    * at the same time; threads might draw different parts of the same AVFrame,
    * or multiple AVFrames, and there is no guarantee that slices will be drawn
    * in order.
    * The function is also used by hardware acceleration APIs.
    * It is called at least once during frame decoding to pass
    * the data needed for hardware render.
    * In that mode instead of pixel data, AVFrame points to
    * a structure specific to the acceleration API. The application
    * reads the structure and can change some fields to indicate progress
    * or mark state.
    * - encoding: unused
    * - decoding: Set by user.
    * @param height the height of the slice
    * @param y the y position of the slice
    * @param type 1->top field, 2->bottom field, 3->frame
    * @param offset offset into the AVFrame.data from which the slice should be read
    */
   void (*draw_horiz_band)(struct AVCodecContext *s,
                           const AVFrame *src, int offset[AV_NUM_DATA_POINTERS],
                           int y, int type, int height);

   /**
    * callback to negotiate the pixelFormat
    * @param fmt is the list of formats which are supported by the codec,
    * it is terminated by -1 as 0 is a valid format, the formats are ordered by quality.
    * The first is always the native one.
    * @return the chosen format
    * - encoding: unused
    * - decoding: Set by user, if not set the native format will be chosen.
    */
   enum AVPixelFormat (*get_format)(struct AVCodecContext *s, const enum AVPixelFormat * fmt);

   /**
    * maximum number of B-frames between non-B-frames
    * Note: The output will be delayed by max_b_frames+1 relative to the input.
    * - encoding: Set by user.
    * - decoding: unused
    */
   int max_b_frames;

   /**
    * qscale factor between IP and B-frames
    * If > 0 then the last P-frame quantizer will be used (q= lastp_q*factor+offset).
    * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
    * - encoding: Set by user.
    * - decoding: unused
    */
   float b_quant_factor;

   /** obsolete FIXME remove */
   int rc_strategy;
#define FF_RC_STRATEGY_XVID 1

   int b_frame_strategy;

   /**
    * qscale offset between IP and B-frames
    * - encoding: Set by user.
    * - decoding: unused
    */
   float b_quant_offset;

   /**
    * Size of the frame reordering buffer in the decoder.
    * For MPEG-2 it is 1 IPB or 0 low delay IP.
    * - encoding: Set by libavcodec.
    * - decoding: Set by libavcodec.
    */
   int has_b_frames;

   /**
    * 0-> h263 quant 1-> mpeg quant
    * - encoding: Set by user.
    * - decoding: unused
    */
   int mpeg_quant;

   /**
    * qscale factor between P and I-frames
    * If > 0 then the last p frame quantizer will be used (q= lastp_q*factor+offset).
    * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
    * - encoding: Set by user.
    * - decoding: unused
    */
   float i_quant_factor;

   /**
    * qscale offset between P and I-frames
    * - encoding: Set by user.
    * - decoding: unused
    */
   float i_quant_offset;

   /**
    * luminance masking (0-> disabled)
    * - encoding: Set by user.
    * - decoding: unused
    */
   float lumi_masking;

   /**
    * temporary complexity masking (0-> disabled)
    * - encoding: Set by user.
    * - decoding: unused
    */
   float temporal_cplx_masking;

   /**
    * spatial complexity masking (0-> disabled)
    * - encoding: Set by user.
    * - decoding: unused
    */
   float spatial_cplx_masking;

   /**
    * p block masking (0-> disabled)
    * - encoding: Set by user.
    * - decoding: unused
    */
   float p_masking;

   /**
    * darkness masking (0-> disabled)
    * - encoding: Set by user.
    * - decoding: unused
    */
   float dark_masking;

   /**
    * slice count
    * - encoding: Set by libavcodec.
    * - decoding: Set by user (or 0).
    */
   int slice_count;
   /**
    * prediction method (needed for huffyuv)
    * - encoding: Set by user.
    * - decoding: unused
    */
    int prediction_method;
#define FF_PRED_LEFT   0
#define FF_PRED_PLANE  1
#define FF_PRED_MEDIAN 2

   /**
    * slice offsets in the frame in bytes
    * - encoding: Set/allocated by libavcodec.
    * - decoding: Set/allocated by user (or NULL).
    */
   int *slice_offset;

   /**
    * sample aspect ratio (0 if unknown)
    * That is the width of a pixel divided by the height of the pixel.
    * Numerator and denominator must be relatively prime and smaller than 256 for some video standards.
    * - encoding: Set by user.
    * - decoding: Set by libavcodec.
    */
   AVRational sample_aspect_ratio;

   /**
    * motion estimation comparison function
    * - encoding: Set by user.
    * - decoding: unused
    */
   int me_cmp;
   /**
    * subpixel motion estimation comparison function
    * - encoding: Set by user.
    * - decoding: unused
    */
   int me_sub_cmp;
   /**
    * macroblock comparison function (not supported yet)
    * - encoding: Set by user.
    * - decoding: unused
    */
   int mb_cmp;
   /**
    * interlaced DCT comparison function
    * - encoding: Set by user.
    * - decoding: unused
    */
   int ildct_cmp;
#define FF_CMP_SAD    0
#define FF_CMP_SSE    1
#define FF_CMP_SATD   2
#define FF_CMP_DCT    3
#define FF_CMP_PSNR   4
#define FF_CMP_BIT    5
#define FF_CMP_RD     6
#define FF_CMP_ZERO   7
#define FF_CMP_VSAD   8
#define FF_CMP_VSSE   9
#define FF_CMP_NSSE   10
#define FF_CMP_DCTMAX 13
#define FF_CMP_DCT264 14
#define FF_CMP_CHROMA 256

   /**
    * ME diamond size & shape
    * - encoding: Set by user.
    * - decoding: unused
    */
   int dia_size;

   /**
    * amount of previous MV predictors (2a+1 x 2a+1 square)
    * - encoding: Set by user.
    * - decoding: unused
    */
   int last_predictor_count;

   /**
    * prepass for motion estimation
    * - encoding: Set by user.
    * - decoding: unused
    */
   int pre_me;

   /**
    * motion estimation prepass comparison function
    * - encoding: Set by user.
    * - decoding: unused
    */
   int me_pre_cmp;

   /**
    * ME prepass diamond size & shape
    * - encoding: Set by user.
    * - decoding: unused
    */
   int pre_dia_size;

   /**
    * subpel ME quality
    * - encoding: Set by user.
    * - decoding: unused
    */
   int me_subpel_quality;

   /**
    * DTG active format information (additional aspect ratio
    * information only used in DVB MPEG-2 transport streams)
    * 0 if not set.
    *
    * - encoding: unused
    * - decoding: Set by decoder.
    */
   int dtg_active_format;
#define FF_DTG_AFD_SAME         8
#define FF_DTG_AFD_4_3          9
#define FF_DTG_AFD_16_9         10
#define FF_DTG_AFD_14_9         11
#define FF_DTG_AFD_4_3_SP_14_9  13
#define FF_DTG_AFD_16_9_SP_14_9 14
#define FF_DTG_AFD_SP_4_3       15

   /**
    * maximum motion estimation search range in subpel units
    * If 0 then no limit.
    *
    * - encoding: Set by user.
    * - decoding: unused
    */
   int me_range;

   /**
    * intra quantizer bias
    * - encoding: Set by user.
    * - decoding: unused
    */
   int intra_quant_bias;
#define FF_DEFAULT_QUANT_BIAS 999999

   /**
    * inter quantizer bias
    * - encoding: Set by user.
    * - decoding: unused
    */
   int inter_quant_bias;

   /**
    * slice flags
    * - encoding: unused
    * - decoding: Set by user.
    */
   int slice_flags;
#define SLICE_FLAG_CODED_ORDER    0x0001 ///< draw_horiz_band() is called in coded order instead of display
#define SLICE_FLAG_ALLOW_FIELD    0x0002 ///< allow draw_horiz_band() with field slices (MPEG2 field pics)
#define SLICE_FLAG_ALLOW_PLANE    0x0004 ///< allow draw_horiz_band() with 1 component at a time (SVQ1)

#if FF_API_XVMC
   /**
    * XVideo Motion Acceleration
    * - encoding: forbidden
    * - decoding: set by decoder
    * @deprecated XvMC support is slated for removal.
    */
   attribute_deprecated int xvmc_acceleration;
#endif /* FF_API_XVMC */

   /**
    * macroblock decision mode
    * - encoding: Set by user.
    * - decoding: unused
    */
   int mb_decision;
#define FF_MB_DECISION_SIMPLE 0        ///< uses mb_cmp
#define FF_MB_DECISION_BITS   1        ///< chooses the one which needs the fewest bits
#define FF_MB_DECISION_RD     2        ///< rate distortion

   /**
    * custom intra quantization matrix
    * - encoding: Set by user, can be NULL.
    * - decoding: Set by libavcodec.
    */
   uint16_t *intra_matrix;

   /**
    * custom inter quantization matrix
    * - encoding: Set by user, can be NULL.
    * - decoding: Set by libavcodec.
    */
   uint16_t *inter_matrix;

   /**
    * scene change detection threshold
    * 0 is default, larger means fewer detected scene changes.
    * - encoding: Set by user.
    * - decoding: unused
    */
   int scenechange_threshold;

   /**
    * noise reduction strength
    * - encoding: Set by user.
    * - decoding: unused
    */
   int noise_reduction;

   /**
    * Motion estimation threshold below which no motion estimation is
    * performed, but instead the user specified motion vectors are used.
    *
    * - encoding: Set by user.
    * - decoding: unused
    */
   int me_threshold;

   /**
    * Macroblock threshold below which the user specified macroblock types will be used.
    * - encoding: Set by user.
    * - decoding: unused
    */
   int mb_threshold;

   /**
    * precision of the intra DC coefficient - 8
    * - encoding: Set by user.
    * - decoding: unused
    */
   int intra_dc_precision;

   /**
    * Number of macroblock rows at the top which are skipped.
    * - encoding: unused
    * - decoding: Set by user.
    */
   int skip_top;

   /**
    * Number of macroblock rows at the bottom which are skipped.
    * - encoding: unused
    * - decoding: Set by user.
    */
   int skip_bottom;

   /**
    * Border processing masking, raises the quantizer for mbs on the borders
    * of the picture.
    * - encoding: Set by user.
    * - decoding: unused
    */
   float border_masking;

   /**
    * minimum MB lagrange multipler
    * - encoding: Set by user.
    * - decoding: unused
    */
   int mb_lmin;

   /**
    * maximum MB lagrange multipler
    * - encoding: Set by user.
    * - decoding: unused
    */
   int mb_lmax;

   /**
    *
    * - encoding: Set by user.
    * - decoding: unused
    */
   int me_penalty_compensation;

   /**
    *
    * - encoding: Set by user.
    * - decoding: unused
    */
   int bidir_refine;

   /**
    *
    * - encoding: Set by user.
    * - decoding: unused
    */
   int brd_scale;

   /**
    * minimum GOP size
    * - encoding: Set by user.
    * - decoding: unused
    */
   int keyint_min;

   /**
    * number of reference frames
    * - encoding: Set by user.
    * - decoding: Set by lavc.
    */
   int refs;

   /**
    * chroma qp offset from luma
    * - encoding: Set by user.
    * - decoding: unused
    */
   int chromaoffset;

   /**
    * Multiplied by qscale for each frame and added to scene_change_score.
    * - encoding: Set by user.
    * - decoding: unused
    */
   int scenechange_factor;

   /**
    *
    * Note: Value depends upon the compare function used for fullpel ME.
    * - encoding: Set by user.
    * - decoding: unused
    */
   int mv0_threshold;

   /**
    * Adjust sensitivity of b_frame_strategy 1.
    * - encoding: Set by user.
    * - decoding: unused
    */
   int b_sensitivity;

   /**
    * Chromaticity coordinates of the source primaries.
    * - encoding: Set by user
    * - decoding: Set by libavcodec
    */
   enum AVColorPrimaries color_primaries;

   /**
    * Color Transfer Characteristic.
    * - encoding: Set by user
    * - decoding: Set by libavcodec
    */
   enum AVColorTransferCharacteristic color_trc;

   /**
    * YUV colorspace type.
    * - encoding: Set by user
    * - decoding: Set by libavcodec
    */
   enum AVColorSpace colorspace;

   /**
    * MPEG vs JPEG YUV range.
    * - encoding: Set by user
    * - decoding: Set by libavcodec
    */
   enum AVColorRange color_range;

   /**
    * This defines the location of chroma samples.
    * - encoding: Set by user
    * - decoding: Set by libavcodec
    */
   enum AVChromaLocation chroma_sample_location;

   /**
    * Number of slices.
    * Indicates number of picture subdivisions. Used for parallelized
    * decoding.
    * - encoding: Set by user
    * - decoding: unused
    */
   int slices;

   /** Field order
    * - encoding: set by libavcodec
    * - decoding: Set by libavcodec
    */
   enum AVFieldOrder field_order;

   /* audio only */
   int sample_rate; ///< samples per second
   int channels;    ///< number of audio channels

   /**
    * audio sample format
    * - encoding: Set by user.
    * - decoding: Set by libavcodec.
    */
   enum AVSampleFormat sample_fmt;  ///< sample format

   /* The following data should not be initialized. */
   /**
    * Number of samples per channel in an audio frame.
    *
    * - encoding: set by libavcodec in avcodec_open2(). Each submitted frame
    *   except the last must contain exactly frame_size samples per channel.
    *   May be 0 when the codec has CODEC_CAP_VARIABLE_FRAME_SIZE set, then the
    *   frame size is not restricted.
    * - decoding: may be set by some decoders to indicate constant frame size
    */
   int frame_size;

   /**
    * Frame counter, set by libavcodec.
    *
    * - decoding: total number of frames returned from the decoder so far.
    * - encoding: total number of frames passed to the encoder so far.
    *
    *   @note the counter is not incremented if encoding/decoding resulted in
    *   an error.
    */
   int frame_number;

   /**
    * number of bytes per packet if constant and known or 0
    * Used by some WAV based audio codecs.
    */
   int block_align;

   /**
    * Audio cutoff bandwidth (0 means "automatic")
    * - encoding: Set by user.
    * - decoding: unused
    */
   int cutoff;

#if FF_API_REQUEST_CHANNELS
   /**
    * Decoder should decode to this many channels if it can (0 for default)
    * - encoding: unused
    * - decoding: Set by user.
    * @deprecated Deprecated in favor of request_channel_layout.
    */
   attribute_deprecated int request_channels;
#endif

   /**
    * Audio channel layout.
    * - encoding: set by user.
    * - decoding: set by libavcodec.
    */
   uint64_t channel_layout;

   /**
    * Request decoder to use this channel layout if it can (0 for default)
    * - encoding: unused
    * - decoding: Set by user.
    */
   uint64_t request_channel_layout;

   /**
    * Type of service that the audio stream conveys.
    * - encoding: Set by user.
    * - decoding: Set by libavcodec.
    */
   enum AVAudioServiceType audio_service_type;

   /**
    * Used to request a sample format from the decoder.
    * - encoding: unused.
    * - decoding: Set by user.
    */
   enum AVSampleFormat request_sample_fmt;

#if FF_API_GET_BUFFER
   /**
    * Called at the beginning of each frame to get a buffer for it.
    *
    * The function will set AVFrame.data[], AVFrame.linesize[].
    * AVFrame.extended_data[] must also be set, but it should be the same as
    * AVFrame.data[] except for planar audio with more channels than can fit
    * in AVFrame.data[]. In that case, AVFrame.data[] shall still contain as
    * many data pointers as it can hold.
    *
    * if CODEC_CAP_DR1 is not set then get_buffer() must call
    * avcodec_default_get_buffer() instead of providing buffers allocated by
    * some other means.
    *
    * AVFrame.data[] should be 32- or 16-byte-aligned unless the CPU doesn't
    * need it. avcodec_default_get_buffer() aligns the output buffer properly,
    * but if get_buffer() is overridden then alignment considerations should
    * be taken into account.
    *
    * @see avcodec_default_get_buffer()
    *
    * Video:
    *
    * If pic.reference is set then the frame will be read later by libavcodec.
    * avcodec_align_dimensions2() should be used to find the required width and
    * height, as they normally need to be rounded up to the next multiple of 16.
    *
    * If frame multithreading is used and thread_safe_callbacks is set,
    * it may be called from a different thread, but not from more than one at
    * once. Does not need to be reentrant.
    *
    * @see release_buffer(), reget_buffer()
    * @see avcodec_align_dimensions2()
    *
    * Audio:
    *
    * Decoders request a buffer of a particular size by setting
    * AVFrame.nb_samples prior to calling get_buffer(). The decoder may,
    * however, utilize only part of the buffer by setting AVFrame.nb_samples
    * to a smaller value in the output frame.
    *
    * Decoders cannot use the buffer after returning from
    * avcodec_decode_audio4(), so they will not call release_buffer(), as it
    * is assumed to be released immediately upon return. In some rare cases,
    * a decoder may need to call get_buffer() more than once in a single
    * call to avcodec_decode_audio4(). In that case, when get_buffer() is
    * called again after it has already been called once, the previously
    * acquired buffer is assumed to be released at that time and may not be
    * reused by the decoder.
    *
    * As a convenience, av_samples_get_buffer_size() and
    * av_samples_fill_arrays() in libavutil may be used by custom get_buffer()
    * functions to find the required data size and to fill data pointers and
    * linesize. In AVFrame.linesize, only linesize[0] may be set for audio
    * since all planes must be the same size.
    *
    * @see av_samples_get_buffer_size(), av_samples_fill_arrays()
    *
    * - encoding: unused
    * - decoding: Set by libavcodec, user can override.
    *
    * @deprecated use get_buffer2()
    */
   attribute_deprecated
   int (*get_buffer)(struct AVCodecContext *c, AVFrame *pic);

   /**
    * Called to release buffers which were allocated with get_buffer.
    * A released buffer can be reused in get_buffer().
    * pic.data[*] must be set to NULL.
    * May be called from a different thread if frame multithreading is used,
    * but not by more than one thread at once, so does not need to be reentrant.
    * - encoding: unused
    * - decoding: Set by libavcodec, user can override.
    *
    * @deprecated custom freeing callbacks should be set from get_buffer2()
    */
   attribute_deprecated
   void (*release_buffer)(struct AVCodecContext *c, AVFrame *pic);

   /**
    * Called at the beginning of a frame to get cr buffer for it.
    * Buffer type (size, hints) must be the same. libavcodec won't check it.
    * libavcodec will pass previous buffer in pic, function should return
    * same buffer or new buffer with old frame "painted" into it.
    * If pic.data[0] == NULL must behave like get_buffer().
    * if CODEC_CAP_DR1 is not set then reget_buffer() must call
    * avcodec_default_reget_buffer() instead of providing buffers allocated by
    * some other means.
    * - encoding: unused
    * - decoding: Set by libavcodec, user can override.
    */
   attribute_deprecated
   int (*reget_buffer)(struct AVCodecContext *c, AVFrame *pic);
#endif

   /**
    * This callback is called at the beginning of each frame to get data
    * buffer(s) for it. There may be one contiguous buffer for all the data or
    * there may be a buffer per each data plane or anything in between. What
    * this means is, you may set however many entries in buf[] you feel necessary.
    * Each buffer must be reference-counted using the AVBuffer API (see description
    * of buf[] below).
    *
    * The following fields will be set in the frame before this callback is
    * called:
    * - format
    * - width, height (video only)
    * - sample_rate, channel_layout, nb_samples (audio only)
    * Their values may differ from the corresponding values in
    * AVCodecContext. This callback must use the frame values, not the codec
    * context values, to calculate the required buffer size.
    *
    * This callback must fill the following fields in the frame:
    * - data[]
    * - linesize[]
    * - extended_data:
    *   * if the data is planar audio with more than 8 channels, then this
    *     callback must allocate and fill extended_data to contain all pointers
    *     to all data planes. data[] must hold as many pointers as it can.
    *     extended_data must be allocated with av_malloc() and will be freed in
    *     av_frame_unref().
    *   * otherwise exended_data must point to data
    * - buf[] must contain one or more pointers to AVBufferRef structures. Each of
    *   the frame's data and extended_data pointers must be contained in these. That
    *   is, one AVBufferRef for each allocated chunk of memory, not necessarily one
    *   AVBufferRef per data[] entry. See: av_buffer_create(), av_buffer_alloc(),
    *   and av_buffer_ref().
    * - extended_buf and nb_extended_buf must be allocated with av_malloc() by
    *   this callback and filled with the extra buffers if there are more
    *   buffers than buf[] can hold. extended_buf will be freed in
    *   av_frame_unref().
    *
    * If CODEC_CAP_DR1 is not set then get_buffer2() must call
    * avcodec_default_get_buffer2() instead of providing buffers allocated by
    * some other means.
    *
    * Each data plane must be aligned to the maximum required by the target
    * CPU.
    *
    * @see avcodec_default_get_buffer2()
    *
    * Video:
    *
    * If AV_GET_BUFFER_FLAG_REF is set in flags then the frame may be reused
    * (read and/or written to if it is writable) later by libavcodec.
    *
    * avcodec_align_dimensions2() should be used to find the required width and
    * height, as they normally need to be rounded up to the next multiple of 16.
    *
    * If frame multithreading is used and thread_safe_callbacks is set,
    * this callback may be called from a different thread, but not from more
    * than one at once. Does not need to be reentrant.
    *
    * @see avcodec_align_dimensions2()
    *
    * Audio:
    *
    * Decoders request a buffer of a particular size by setting
    * AVFrame.nb_samples prior to calling get_buffer2(). The decoder may,
    * however, utilize only part of the buffer by setting AVFrame.nb_samples
    * to a smaller value in the output frame.
    *
    * As a convenience, av_samples_get_buffer_size() and
    * av_samples_fill_arrays() in libavutil may be used by custom get_buffer2()
    * functions to find the required data size and to fill data pointers and
    * linesize. In AVFrame.linesize, only linesize[0] may be set for audio
    * since all planes must be the same size.
    *
    * @see av_samples_get_buffer_size(), av_samples_fill_arrays()
    *
    * - encoding: unused
    * - decoding: Set by libavcodec, user can override.
    */
   int (*get_buffer2)(struct AVCodecContext *s, AVFrame *frame, int flags);

   /**
    * If non-zero, the decoded audio and video frames returned from
    * avcodec_decode_video2() and avcodec_decode_audio4() are reference-counted
    * and are valid indefinitely. The caller must free them with
    * av_frame_unref() when they are not needed anymore.
    * Otherwise, the decoded frames must not be freed by the caller and are
    * only valid until the next decode call.
    *
    * - encoding: unused
    * - decoding: set by the caller before avcodec_open2().
    */
   int refcounted_frames;

   /* - encoding parameters */
   float qcompress;  ///< amount of qscale change between easy & hard scenes (0.0-1.0)
   float qblur;      ///< amount of qscale smoothing over time (0.0-1.0)

   /**
    * minimum quantizer
    * - encoding: Set by user.
    * - decoding: unused
    */
   int qmin;

   /**
    * maximum quantizer
    * - encoding: Set by user.
    * - decoding: unused
    */
   int qmax;

   /**
    * maximum quantizer difference between frames
    * - encoding: Set by user.
    * - decoding: unused
    */
   int max_qdiff;

   /**
    * ratecontrol qmin qmax limiting method
    * 0-> clipping, 1-> use a nice continuous function to limit qscale wthin qmin/qmax.
    * - encoding: Set by user.
    * - decoding: unused
    */
   float rc_qsquish;

   float rc_qmod_amp;
   int rc_qmod_freq;

   /**
    * decoder bitstream buffer size
    * - encoding: Set by user.
    * - decoding: unused
    */
   int rc_buffer_size;

   /**
    * ratecontrol override, see RcOverride
    * - encoding: Allocated/set/freed by user.
    * - decoding: unused
    */
   int rc_override_count;
   RcOverride *rc_override;

   /**
    * rate control equation
    * - encoding: Set by user
    * - decoding: unused
    */
   const char *rc_eq;

   /**
    * maximum bitrate
    * - encoding: Set by user.
    * - decoding: unused
    */
   int rc_max_rate;

   /**
    * minimum bitrate
    * - encoding: Set by user.
    * - decoding: unused
    */
   int rc_min_rate;

   float rc_buffer_aggressivity;

   /**
    * initial complexity for pass1 ratecontrol
    * - encoding: Set by user.
    * - decoding: unused
    */
   float rc_initial_cplx;

   /**
    * Ratecontrol attempt to use, at maximum, <value> of what can be used without an underflow.
    * - encoding: Set by user.
    * - decoding: unused.
    */
   float rc_max_available_vbv_use;

   /**
    * Ratecontrol attempt to use, at least, <value> times the amount needed to prevent a vbv overflow.
    * - encoding: Set by user.
    * - decoding: unused.
    */
   float rc_min_vbv_overflow_use;

   /**
    * Number of bits which should be loaded into the rc buffer before decoding starts.
    * - encoding: Set by user.
    * - decoding: unused
    */
   int rc_initial_buffer_occupancy;

#define FF_CODER_TYPE_VLC       0
#define FF_CODER_TYPE_AC        1
#define FF_CODER_TYPE_RAW       2
#define FF_CODER_TYPE_RLE       3
#define FF_CODER_TYPE_DEFLATE   4
   /**
    * coder type
    * - encoding: Set by user.
    * - decoding: unused
    */
   int coder_type;

   /**
    * context model
    * - encoding: Set by user.
    * - decoding: unused
    */
   int context_model;

   /**
    * minimum Lagrange multipler
    * - encoding: Set by user.
    * - decoding: unused
    */
   int lmin;

   /**
    * maximum Lagrange multipler
    * - encoding: Set by user.
    * - decoding: unused
    */
   int lmax;

   /**
    * frame skip threshold
    * - encoding: Set by user.
    * - decoding: unused
    */
   int frame_skip_threshold;

   /**
    * frame skip factor
    * - encoding: Set by user.
    * - decoding: unused
    */
   int frame_skip_factor;

   /**
    * frame skip exponent
    * - encoding: Set by user.
    * - decoding: unused
    */
   int frame_skip_exp;

   /**
    * frame skip comparison function
    * - encoding: Set by user.
    * - decoding: unused
    */
   int frame_skip_cmp;

   /**
    * trellis RD quantization
    * - encoding: Set by user.
    * - decoding: unused
    */
   int trellis;

   /**
    * - encoding: Set by user.
    * - decoding: unused
    */
   int min_prediction_order;

   /**
    * - encoding: Set by user.
    * - decoding: unused
    */
   int max_prediction_order;

   /**
    * GOP timecode frame start number, in non drop frame format
    * - encoding: Set by user.
    * - decoding: unused
    */
   int64_t timecode_frame_start;

   /* The RTP callback: This function is called    */
   /* every time the encoder has a packet to send. */
   /* It depends on the encoder if the data starts */
   /* with a Start Code (it should). H.263 does.   */
   /* mb_nb contains the number of macroblocks     */
   /* encoded in the RTP payload.                  */
   void (*rtp_callback)(struct AVCodecContext *avctx, void *data, int size, int mb_nb);

   int rtp_payload_size;   /* The size of the RTP payload: the coder will  */
                           /* do its best to deliver a chunk with size     */
                           /* below rtp_payload_size, the chunk will start */
                           /* with a start code on some codecs like H.263. */
                           /* This doesn't take account of any particular  */
                           /* headers inside the transmitted RTP payload.  */

   /* statistics, used for 2-pass encoding */
   int mv_bits;
   int header_bits;
   int i_tex_bits;
   int p_tex_bits;
   int i_count;
   int p_count;
   int skip_count;
   int misc_bits;

   /**
    * number of bits used for the previously encoded frame
    * - encoding: Set by libavcodec.
    * - decoding: unused
    */
   int frame_bits;

   /**
    * pass1 encoding statistics output buffer
    * - encoding: Set by libavcodec.
    * - decoding: unused
    */
   char *stats_out;

   /**
    * pass2 encoding statistics input buffer
    * Concatenated stuff from stats_out of pass1 should be placed here.
    * - encoding: Allocated/set/freed by user.
    * - decoding: unused
    */
   char *stats_in;

   /**
    * Work around bugs in encoders which sometimes cannot be detected automatically.
    * - encoding: Set by user
    * - decoding: Set by user
    */
   int workaround_bugs;
#define FF_BUG_AUTODETECT       1  ///< autodetection
#if FF_API_OLD_MSMPEG4
#define FF_BUG_OLD_MSMPEG4      2
#endif
#define FF_BUG_XVID_ILACE       4
#define FF_BUG_UMP4             8
#define FF_BUG_NO_PADDING       16
#define FF_BUG_AMV              32
#if FF_API_AC_VLC
#define FF_BUG_AC_VLC           0  ///< Will be removed, libavcodec can now handle these non-compliant files by default.
#endif
#define FF_BUG_QPEL_CHROMA      64
#define FF_BUG_STD_QPEL         128
#define FF_BUG_QPEL_CHROMA2     256
#define FF_BUG_DIRECT_BLOCKSIZE 512
#define FF_BUG_EDGE             1024
#define FF_BUG_HPEL_CHROMA      2048
#define FF_BUG_DC_CLIP          4096
#define FF_BUG_MS               8192 ///< Work around various bugs in Microsoft's broken decoders.
#define FF_BUG_TRUNCATED       16384

   /**
    * strictly follow the standard (MPEG4, ...).
    * - encoding: Set by user.
    * - decoding: Set by user.
    * Setting this to STRICT or higher means the encoder and decoder will
    * generally do stupid things, whereas setting it to unofficial or lower
    * will mean the encoder might produce output that is not supported by all
    * spec-compliant decoders. Decoders don't differentiate between normal,
    * unofficial and experimental (that is, they always try to decode things
    * when they can) unless they are explicitly asked to behave stupidly
    * (=strictly conform to the specs)
    */
   int strict_std_compliance;
#define FF_COMPLIANCE_VERY_STRICT   2 ///< Strictly conform to an older more strict version of the spec or reference software.
#define FF_COMPLIANCE_STRICT        1 ///< Strictly conform to all the things in the spec no matter what consequences.
#define FF_COMPLIANCE_NORMAL        0
#define FF_COMPLIANCE_UNOFFICIAL   -1 ///< Allow unofficial extensions
#define FF_COMPLIANCE_EXPERIMENTAL -2 ///< Allow nonstandardized experimental things.

   /**
    * error concealment flags
    * - encoding: unused
    * - decoding: Set by user.
    */
   int error_concealment;
#define FF_EC_GUESS_MVS   1
#define FF_EC_DEBLOCK     2

   /**
    * debug
    * - encoding: Set by user.
    * - decoding: Set by user.
    */
   int debug;
#define FF_DEBUG_PICT_INFO   1
#define FF_DEBUG_RC          2
#define FF_DEBUG_BITSTREAM   4
#define FF_DEBUG_MB_TYPE     8
#define FF_DEBUG_QP          16
#if FF_API_DEBUG_MV
/**
* @deprecated this option does nothing
*/
#define FF_DEBUG_MV          32
#endif
#define FF_DEBUG_DCT_COEFF   0x00000040
#define FF_DEBUG_SKIP        0x00000080
#define FF_DEBUG_STARTCODE   0x00000100
#define FF_DEBUG_PTS         0x00000200
#define FF_DEBUG_ER          0x00000400
#define FF_DEBUG_MMCO        0x00000800
#define FF_DEBUG_BUGS        0x00001000
#if FF_API_DEBUG_MV
#define FF_DEBUG_VIS_QP      0x00002000
#define FF_DEBUG_VIS_MB_TYPE 0x00004000
#endif
#define FF_DEBUG_BUFFERS     0x00008000
#define FF_DEBUG_THREADS     0x00010000

#if FF_API_DEBUG_MV
   /**
    * @deprecated this option does not have any effect
    */
   attribute_deprecated
   int debug_mv;
#define FF_DEBUG_VIS_MV_P_FOR  0x00000001 //visualize forward predicted MVs of P frames
#define FF_DEBUG_VIS_MV_B_FOR  0x00000002 //visualize forward predicted MVs of B frames
#define FF_DEBUG_VIS_MV_B_BACK 0x00000004 //visualize backward predicted MVs of B frames
#endif

   /**
    * Error recognition; may misdetect some more or less valid parts as errors.
    * - encoding: unused
    * - decoding: Set by user.
    */
   int err_recognition;

/**
* Verify checksums embedded in the bitstream (could be of either encoded or
* decoded data, depending on the codec) and print an error message on mismatch.
* If AV_EF_EXPLODE is also set, a mismatching checksum will result in the
* decoder returning an error.
*/
#define AV_EF_CRCCHECK  (1<<0)
#define AV_EF_BITSTREAM (1<<1)
#define AV_EF_BUFFER    (1<<2)
#define AV_EF_EXPLODE   (1<<3)

   /**
    * opaque 64bit number (generally a PTS) that will be reordered and
    * output in AVFrame.reordered_opaque
    * @deprecated in favor of pkt_pts
    * - encoding: unused
    * - decoding: Set by user.
    */
   int64_t reordered_opaque;

   /**
    * Hardware accelerator in use
    * - encoding: unused.
    * - decoding: Set by libavcodec
    */
   struct AVHWAccel *hwaccel;

   /**
    * Hardware accelerator context.
    * For some hardware accelerators, a global context needs to be
    * provided by the user. In that case, this holds display-dependent
    * data Libav cannot instantiate itself. Please refer to the
    * Libav HW accelerator documentation to know how to fill this
    * is. e.g. for VA API, this is a struct vaapi_context.
    * - encoding: unused
    * - decoding: Set by user
    */
   void *hwaccel_context;

   /**
    * error
    * - encoding: Set by libavcodec if flags&CODEC_FLAG_PSNR.
    * - decoding: unused
    */
   uint64_t error[AV_NUM_DATA_POINTERS];

   /**
    * DCT algorithm, see FF_DCT_* below
    * - encoding: Set by user.
    * - decoding: unused
    */
   int dct_algo;
#define FF_DCT_AUTO    0
#define FF_DCT_FASTINT 1
#define FF_DCT_INT     2
#define FF_DCT_MMX     3
#define FF_DCT_ALTIVEC 5
#define FF_DCT_FAAN    6

   /**
    * IDCT algorithm, see FF_IDCT_* below.
    * - encoding: Set by user.
    * - decoding: Set by user.
    */
   int idct_algo;
#define FF_IDCT_AUTO          0
#define FF_IDCT_INT           1
#define FF_IDCT_SIMPLE        2
#define FF_IDCT_SIMPLEMMX     3
#define FF_IDCT_ARM           7
#define FF_IDCT_ALTIVEC       8
#define FF_IDCT_SH4           9
#define FF_IDCT_SIMPLEARM     10
#define FF_IDCT_IPP           13
#define FF_IDCT_XVIDMMX       14
#define FF_IDCT_SIMPLEARMV5TE 16
#define FF_IDCT_SIMPLEARMV6   17
#define FF_IDCT_SIMPLEVIS     18
#define FF_IDCT_FAAN          20
#define FF_IDCT_SIMPLENEON    22
#if FF_API_ARCH_ALPHA
#define FF_IDCT_SIMPLEALPHA   23
#endif

   /**
    * bits per sample/pixel from the demuxer (needed for huffyuv).
    * - encoding: Set by libavcodec.
    * - decoding: Set by user.
    */
    int bits_per_coded_sample;

   /**
    * Bits per sample/pixel of internal libavcodec pixel/sample format.
    * - encoding: set by user.
    * - decoding: set by libavcodec.
    */
   int bits_per_raw_sample;

#if FF_API_LOWRES
   /**
    * low resolution decoding, 1-> 1/2 size, 2->1/4 size
    * - encoding: unused
    * - decoding: Set by user.
    *
    * @deprecated use decoder private options instead
    */
   attribute_deprecated int lowres;
#endif

   /**
    * the picture in the bitstream
    * - encoding: Set by libavcodec.
    * - decoding: unused
    */
   AVFrame *coded_frame;

   /**
    * thread count
    * is used to decide how many independent tasks should be passed to execute()
    * - encoding: Set by user.
    * - decoding: Set by user.
    */
   int thread_count;

   /**
    * Which multithreading methods to use.
    * Use of FF_THREAD_FRAME will increase decoding delay by one frame per thread,
    * so clients which cannot provide future frames should not use it.
    *
    * - encoding: Set by user, otherwise the default is used.
    * - decoding: Set by user, otherwise the default is used.
    */
   int thread_type;
#define FF_THREAD_FRAME   1 ///< Decode more than one frame at once
#define FF_THREAD_SLICE   2 ///< Decode more than one part of a single frame at once

   /**
    * Which multithreading methods are in use by the codec.
    * - encoding: Set by libavcodec.
    * - decoding: Set by libavcodec.
    */
   int active_thread_type;

   /**
    * Set by the client if its custom get_buffer() callback can be called
    * synchronously from another thread, which allows faster multithreaded decoding.
    * draw_horiz_band() will be called from other threads regardless of this setting.
    * Ignored if the default get_buffer() is used.
    * - encoding: Set by user.
    * - decoding: Set by user.
    */
   int thread_safe_callbacks;

   /**
    * The codec may call this to execute several independent things.
    * It will return only after finishing all tasks.
    * The user may replace this with some multithreaded implementation,
    * the default implementation will execute the parts serially.
    * @param count the number of things to execute
    * - encoding: Set by libavcodec, user can override.
    * - decoding: Set by libavcodec, user can override.
    */
   int (*execute)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg), void *arg2, int *ret, int count, int size);

   /**
    * The codec may call this to execute several independent things.
    * It will return only after finishing all tasks.
    * The user may replace this with some multithreaded implementation,
    * the default implementation will execute the parts serially.
    * Also see avcodec_thread_init and e.g. the --enable-pthread configure option.
    * @param c context passed also to func
    * @param count the number of things to execute
    * @param arg2 argument passed unchanged to func
    * @param ret return values of executed functions, must have space for "count" values. May be NULL.
    * @param func function that will be called count times, with jobnr from 0 to count-1.
    *             threadnr will be in the range 0 to c->thread_count-1 < MAX_THREADS and so that no
    *             two instances of func executing at the same time will have the same threadnr.
    * @return always 0 currently, but code should handle a future improvement where when any call to func
    *         returns < 0 no further calls to func may be done and < 0 is returned.
    * - encoding: Set by libavcodec, user can override.
    * - decoding: Set by libavcodec, user can override.
    */
   int (*execute2)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg, int jobnr, int threadnr), void *arg2, int *ret, int count);

#if FF_API_THREAD_OPAQUE
   /**
    * @deprecated this field should not be used from outside of lavc
    */
   attribute_deprecated
   void *thread_opaque;
#endif

   /**
    * noise vs. sse weight for the nsse comparsion function
    * - encoding: Set by user.
    * - decoding: unused
    */
    int nsse_weight;

   /**
    * profile
    * - encoding: Set by user.
    * - decoding: Set by libavcodec.
    */
    int profile;
#define FF_PROFILE_UNKNOWN -99
#define FF_PROFILE_RESERVED -100

#define FF_PROFILE_AAC_MAIN 0
#define FF_PROFILE_AAC_LOW  1
#define FF_PROFILE_AAC_SSR  2
#define FF_PROFILE_AAC_LTP  3
#define FF_PROFILE_AAC_HE   4
#define FF_PROFILE_AAC_HE_V2 28
#define FF_PROFILE_AAC_LD   22
#define FF_PROFILE_AAC_ELD  38
#define FF_PROFILE_MPEG2_AAC_LOW 128
#define FF_PROFILE_MPEG2_AAC_HE  131

#define FF_PROFILE_DTS         20
#define FF_PROFILE_DTS_ES      30
#define FF_PROFILE_DTS_96_24   40
#define FF_PROFILE_DTS_HD_HRA  50
#define FF_PROFILE_DTS_HD_MA   60

#define FF_PROFILE_MPEG2_422    0
#define FF_PROFILE_MPEG2_HIGH   1
#define FF_PROFILE_MPEG2_SS     2
#define FF_PROFILE_MPEG2_SNR_SCALABLE  3
#define FF_PROFILE_MPEG2_MAIN   4
#define FF_PROFILE_MPEG2_SIMPLE 5

#define FF_PROFILE_H264_CONSTRAINED  (1<<9)  // 8+1; constraint_set1_flag
#define FF_PROFILE_H264_INTRA        (1<<11) // 8+3; constraint_set3_flag

#define FF_PROFILE_H264_BASELINE             66
#define FF_PROFILE_H264_CONSTRAINED_BASELINE (66|FF_PROFILE_H264_CONSTRAINED)
#define FF_PROFILE_H264_MAIN                 77
#define FF_PROFILE_H264_EXTENDED             88
#define FF_PROFILE_H264_HIGH                 100
#define FF_PROFILE_H264_HIGH_10              110
#define FF_PROFILE_H264_HIGH_10_INTRA        (110|FF_PROFILE_H264_INTRA)
#define FF_PROFILE_H264_HIGH_422             122
#define FF_PROFILE_H264_HIGH_422_INTRA       (122|FF_PROFILE_H264_INTRA)
#define FF_PROFILE_H264_HIGH_444             144
#define FF_PROFILE_H264_HIGH_444_PREDICTIVE  244
#define FF_PROFILE_H264_HIGH_444_INTRA       (244|FF_PROFILE_H264_INTRA)
#define FF_PROFILE_H264_CAVLC_444            44

#define FF_PROFILE_VC1_SIMPLE   0
#define FF_PROFILE_VC1_MAIN     1
#define FF_PROFILE_VC1_COMPLEX  2
#define FF_PROFILE_VC1_ADVANCED 3

#define FF_PROFILE_MPEG4_SIMPLE                     0
#define FF_PROFILE_MPEG4_SIMPLE_SCALABLE            1
#define FF_PROFILE_MPEG4_CORE                       2
#define FF_PROFILE_MPEG4_MAIN                       3
#define FF_PROFILE_MPEG4_N_BIT                      4
#define FF_PROFILE_MPEG4_SCALABLE_TEXTURE           5
#define FF_PROFILE_MPEG4_SIMPLE_FACE_ANIMATION      6
#define FF_PROFILE_MPEG4_BASIC_ANIMATED_TEXTURE     7
#define FF_PROFILE_MPEG4_HYBRID                     8
#define FF_PROFILE_MPEG4_ADVANCED_REAL_TIME         9
#define FF_PROFILE_MPEG4_CORE_SCALABLE             10
#define FF_PROFILE_MPEG4_ADVANCED_CODING           11
#define FF_PROFILE_MPEG4_ADVANCED_CORE             12
#define FF_PROFILE_MPEG4_ADVANCED_SCALABLE_TEXTURE 13
#define FF_PROFILE_MPEG4_SIMPLE_STUDIO             14
#define FF_PROFILE_MPEG4_ADVANCED_SIMPLE           15

#define FF_PROFILE_JPEG2000_CSTREAM_RESTRICTION_0   0
#define FF_PROFILE_JPEG2000_CSTREAM_RESTRICTION_1   1
#define FF_PROFILE_JPEG2000_CSTREAM_NO_RESTRICTION  2
#define FF_PROFILE_JPEG2000_DCINEMA_2K              3
#define FF_PROFILE_JPEG2000_DCINEMA_4K              4


#define FF_PROFILE_HEVC_MAIN                        1
#define FF_PROFILE_HEVC_MAIN_10                     2
#define FF_PROFILE_HEVC_MAIN_STILL_PICTURE          3

   /**
    * level
    * - encoding: Set by user.
    * - decoding: Set by libavcodec.
    */
    int level;
#define FF_LEVEL_UNKNOWN -99

   /**
    *
    * - encoding: unused
    * - decoding: Set by user.
    */
   enum AVDiscard skip_loop_filter;

   /**
    *
    * - encoding: unused
    * - decoding: Set by user.
    */
   enum AVDiscard skip_idct;

   /**
    *
    * - encoding: unused
    * - decoding: Set by user.
    */
   enum AVDiscard skip_frame;

   /**
    * Header containing style information for text subtitles.
    * For SUBTITLE_ASS subtitle type, it should contain the whole ASS
    * [Script Info] and [V4+ Styles] section, plus the [Events] line and
    * the Format line following. It shouldn't include any Dialogue line.
    * - encoding: Set/allocated/freed by user (before avcodec_open2())
    * - decoding: Set/allocated/freed by libavcodec (by avcodec_open2())
    */
   uint8_t *subtitle_header;
   int subtitle_header_size;

#if FF_API_ERROR_RATE
   /**
    * @deprecated use the 'error_rate' private AVOption of the mpegvideo
    * encoders
    */
   attribute_deprecated
   int error_rate;
#endif

#if FF_API_CODEC_PKT
   /**
    * @deprecated this field is not supposed to be accessed from outside lavc
    */
   attribute_deprecated
   AVPacket *pkt;
#endif

   /**
    * VBV delay coded in the last frame (in periods of a 27 MHz clock).
    * Used for compliant TS muxing.
    * - encoding: Set by libavcodec.
    * - decoding: unused.
    */
   uint64_t vbv_delay;
} AVCodecContext;

/**
* AVProfile.
*/
typedef struct AVProfile {
   int profile;
   const char *name; ///< short name for the profile
} AVProfile;

typedef struct AVCodecDefault AVCodecDefault;

struct AVSubtitle;

/**
* AVCodec.
*/
typedef struct AVCodec {
   /**
    * Name of the codec implementation.
    * The name is globally unique among encoders and among decoders (but an
    * encoder and a decoder can share the same name).
    * This is the primary way to find a codec from the user perspective.
    */
   const char *name;
   /**
    * Descriptive name for the codec, meant to be more human readable than name.
    * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
    */
   const char *long_name;
   enum AVMediaType type;
   enum AVCodecID id;
   /**
    * Codec capabilities.
    * see CODEC_CAP_*
    */
   int capabilities;
   const AVRational *supported_framerates; ///< array of supported framerates, or NULL if any, array is terminated by {0,0}
   const enum AVPixelFormat *pix_fmts;     ///< array of supported pixel formats, or NULL if unknown, array is terminated by -1
   const int *supported_samplerates;       ///< array of supported audio samplerates, or NULL if unknown, array is terminated by 0
   const enum AVSampleFormat *sample_fmts; ///< array of supported sample formats, or NULL if unknown, array is terminated by -1
   const uint64_t *channel_layouts;         ///< array of support channel layouts, or NULL if unknown. array is terminated by 0
#if FF_API_LOWRES
   attribute_deprecated uint8_t max_lowres; ///< maximum value for lowres supported by the decoder
#endif
   const AVClass *priv_class;              ///< AVClass for the private context
   const AVProfile *profiles;              ///< array of recognized profiles, or NULL if unknown, array is terminated by {FF_PROFILE_UNKNOWN}

   /*****************************************************************
    * No fields below this line are part of the public API. They
    * may not be used outside of libavcodec and can be changed and
    * removed at will.
    * New public fields should be added right above.
    *****************************************************************
    */
   int priv_data_size;
   struct AVCodec *next;
   /**
    * @name Frame-level threading support functions
    * @{
    */
   /**
    * If defined, called on thread contexts when they are created.
    * If the codec allocates writable tables in init(), re-allocate them here.
    * priv_data will be set to a copy of the original.
    */
   int (*init_thread_copy)(AVCodecContext *);
   /**
    * Copy necessary context variables from a previous thread context to the current one.
    * If not defined, the next thread will start automatically; otherwise, the codec
    * must call ff_thread_finish_setup().
    *
    * dst and src will (rarely) point to the same context, in which case memcpy should be skipped.
    */
   int (*update_thread_context)(AVCodecContext *dst, const AVCodecContext *src);
   /** @} */

   /**
    * Private codec-specific defaults.
    */
   const AVCodecDefault *defaults;

   /**
    * Initialize codec static data, called from avcodec_register().
    */
   void (*init_static_data)(struct AVCodec *codec);

   int (*init)(AVCodecContext *);
   int (*encode_sub)(AVCodecContext *, uint8_t *buf, int buf_size,
                     const struct AVSubtitle *sub);
   /**
    * Encode data to an AVPacket.
    *
    * @param      avctx          codec context
    * @param      avpkt          output AVPacket (may contain a user-provided buffer)
    * @param[in]  frame          AVFrame containing the raw data to be encoded
    * @param[out] got_packet_ptr encoder sets to 0 or 1 to indicate that a
    *                            non-empty packet was returned in avpkt.
    * @return 0 on success, negative error code on failure
    */
   int (*encode2)(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame,
                  int *got_packet_ptr);
   int (*decode)(AVCodecContext *, void *outdata, int *outdata_size, AVPacket *avpkt);
   int (*close)(AVCodecContext *);
   /**
    * Flush buffers.
    * Will be called when seeking
    */
   void (*flush)(AVCodecContext *);
} AVCodec;

/**
* AVHWAccel.
*/
typedef struct AVHWAccel {
   /**
    * Name of the hardware accelerated codec.
    * The name is globally unique among encoders and among decoders (but an
    * encoder and a decoder can share the same name).
    */
   const char *name;

   /**
    * Type of codec implemented by the hardware accelerator.
    *
    * See AVMEDIA_TYPE_xxx
    */
   enum AVMediaType type;

   /**
    * Codec implemented by the hardware accelerator.
    *
    * See AV_CODEC_ID_xxx
    */
   enum AVCodecID id;

   /**
    * Supported pixel format.
    *
    * Only hardware accelerated formats are supported here.
    */
   enum AVPixelFormat pix_fmt;

   /**
    * Hardware accelerated codec capabilities.
    * see FF_HWACCEL_CODEC_CAP_*
    */
   int capabilities;

   struct AVHWAccel *next;

   /**
    * Called at the beginning of each frame or field picture.
    *
    * Meaningful frame information (codec specific) is guaranteed to
    * be parsed at this point. This function is mandatory.
    *
    * Note that buf can be NULL along with buf_size set to 0.
    * Otherwise, this means the whole frame is available at this point.
    *
    * @param avctx the codec context
    * @param buf the frame data buffer base
    * @param buf_size the size of the frame in bytes
    * @return zero if successful, a negative value otherwise
    */
   int (*start_frame)(AVCodecContext *avctx, const uint8_t *buf, uint32_t buf_size);

   /**
    * Callback for each slice.
    *
    * Meaningful slice information (codec specific) is guaranteed to
    * be parsed at this point. This function is mandatory.
    *
    * @param avctx the codec context
    * @param buf the slice data buffer base
    * @param buf_size the size of the slice in bytes
    * @return zero if successful, a negative value otherwise
    */
   int (*decode_slice)(AVCodecContext *avctx, const uint8_t *buf, uint32_t buf_size);

   /**
    * Called at the end of each frame or field picture.
    *
    * The whole picture is parsed at this point and can now be sent
    * to the hardware accelerator. This function is mandatory.
    *
    * @param avctx the codec context
    * @return zero if successful, a negative value otherwise
    */
   int (*end_frame)(AVCodecContext *avctx);

   /**
    * Size of HW accelerator private data.
    *
    * Private data is allocated with av_mallocz() before
    * AVCodecContext.get_buffer() and deallocated after
    * AVCodecContext.release_buffer().
    */
   int priv_data_size;
} AVHWAccel;

/**
* @defgroup lavc_picture AVPicture
*
* Functions for working with AVPicture
* @{
*/

/**
* four components are given, that's all.
* the last component is alpha
*/
typedef struct AVPicture {
   uint8_t *data[AV_NUM_DATA_POINTERS];
   int linesize[AV_NUM_DATA_POINTERS];     ///< number of bytes per line
} AVPicture;

/**
* @}
*/

#define AVPALETTE_SIZE 1024
#define AVPALETTE_COUNT 256

enum AVSubtitleType {
   SUBTITLE_NONE,

   SUBTITLE_BITMAP,                ///< A bitmap, pict will be set

   /**
    * Plain text, the text field must be set by the decoder and is
    * authoritative. ass and pict fields may contain approximations.
    */
   SUBTITLE_TEXT,

   /**
    * Formatted text, the ass field must be set by the decoder and is
    * authoritative. pict and text fields may contain approximations.
    */
   SUBTITLE_ASS,
};

#define AV_SUBTITLE_FLAG_FORCED 0x00000001

typedef struct AVSubtitleRect {
   int x;         ///< top left corner  of pict, undefined when pict is not set
   int y;         ///< top left corner  of pict, undefined when pict is not set
   int w;         ///< width            of pict, undefined when pict is not set
   int h;         ///< height           of pict, undefined when pict is not set
   int nb_colors; ///< number of colors in pict, undefined when pict is not set

   /**
    * data+linesize for the bitmap of this subtitle.
    * can be set for text/ass as well once they where rendered
    */
   AVPicture pict;
   enum AVSubtitleType type;

   char *text;                     ///< 0 terminated plain UTF-8 text

   /**
    * 0 terminated ASS/SSA compatible event line.
    * The pressentation of this is unaffected by the other values in this
    * struct.
    */
   char *ass;
   int flags;
} AVSubtitleRect;

typedef struct AVSubtitle {
   uint16_t format; /* 0 = graphics */
   uint32_t start_display_time; /* relative to packet pts, in ms */
   uint32_t end_display_time; /* relative to packet pts, in ms */
   unsigned num_rects;
   AVSubtitleRect **rects;
   int64_t pts;    ///< Same as packet pts, in AV_TIME_BASE
} AVSubtitle;

/**
* If c is NULL, returns the first registered codec,
* if c is non-NULL, returns the next registered codec after c,
* or NULL if c is the last one.
*/
AVCodec *av_codec_next(const AVCodec *c);

/**
* Return the LIBAVCODEC_VERSION_INT constant.
*/
unsigned avcodec_version(void);

/**
* Return the libavcodec build-time configuration.
*/
const char *avcodec_configuration(void);

/**
* Return the libavcodec license.
*/
const char *avcodec_license(void);

/**
* Register the codec codec and initialize libavcodec.
*
* @warning either this function or avcodec_register_all() must be called
* before any other libavcodec functions.
*
* @see avcodec_register_all()
*/
void avcodec_register(AVCodec *codec);

/**
* Register all the codecs, parsers and bitstream filters which were enabled at
* configuration time. If you do not call this function you can select exactly
* which formats you want to support, by using the individual registration
* functions.
*
* @see avcodec_register
* @see av_register_codec_parser
* @see av_register_bitstream_filter
*/
void avcodec_register_all(void);

/**
* Allocate an AVCodecContext and set its fields to default values.  The
* resulting struct can be deallocated by calling avcodec_close() on it followed
* by av_free().
*
* @param codec if non-NULL, allocate private data and initialize defaults
*              for the given codec. It is illegal to then call avcodec_open2()
*              with a different codec.
*              If NULL, then the codec-specific defaults won't be initialized,
*              which may result in suboptimal default settings (this is
*              important mainly for encoders, e.g. libx264).
*
* @return An AVCodecContext filled with default values or NULL on failure.
* @see avcodec_get_context_defaults
*/
AVCodecContext *avcodec_alloc_context3(const AVCodec *codec);

/**
* Set the fields of the given AVCodecContext to default values corresponding
* to the given codec (defaults may be codec-dependent).
*
* Do not call this function if a non-NULL codec has been passed
* to avcodec_alloc_context3() that allocated this AVCodecContext.
* If codec is non-NULL, it is illegal to call avcodec_open2() with a
* different codec on this AVCodecContext.
*/
int avcodec_get_context_defaults3(AVCodecContext *s, const AVCodec *codec);

/**
* Get the AVClass for AVCodecContext. It can be used in combination with
* AV_OPT_SEARCH_FAKE_OBJ for examining options.
*
* @see av_opt_find().
*/
const AVClass *avcodec_get_class(void);

/**
* Copy the settings of the source AVCodecContext into the destination
* AVCodecContext. The resulting destination codec context will be
* unopened, i.e. you are required to call avcodec_open2() before you
* can use this AVCodecContext to decode/encode video/audio data.
*
* @param dest target codec context, should be initialized with
*             avcodec_alloc_context3(), but otherwise uninitialized
* @param src source codec context
* @return AVERROR() on error (e.g. memory allocation error), 0 on success
*/
int avcodec_copy_context(AVCodecContext *dest, const AVCodecContext *src);

#if FF_API_AVFRAME_LAVC
/**
* @deprecated use av_frame_alloc()
*/
attribute_deprecated
AVFrame *avcodec_alloc_frame(void);

/**
* Set the fields of the given AVFrame to default values.
*
* @param frame The AVFrame of which the fields should be set to default values.
*
* @deprecated use av_frame_unref()
*/
attribute_deprecated
void avcodec_get_frame_defaults(AVFrame *frame);

/**
* Free the frame and any dynamically allocated objects in it,
* e.g. extended_data.
*
* @param frame frame to be freed. The pointer will be set to NULL.
*
* @warning this function does NOT free the data buffers themselves
* (it does not know how, since they might have been allocated with
*  a custom get_buffer()).
*
* @deprecated use av_frame_free()
*/
attribute_deprecated
void avcodec_free_frame(AVFrame **frame);
#endif

/**
* Initialize the AVCodecContext to use the given AVCodec. Prior to using this
* function the context has to be allocated with avcodec_alloc_context3().
*
* The functions avcodec_find_decoder_by_name(), avcodec_find_encoder_by_name(),
* avcodec_find_decoder() and avcodec_find_encoder() provide an easy way for
* retrieving a codec.
*
* @warning This function is not thread safe!
*
* @code
* avcodec_register_all();
* av_dict_set(&opts, "b", "2.5M", 0);
* codec = avcodec_find_decoder(AV_CODEC_ID_H264);
* if (!codec)
*     exit(1);
*
* context = avcodec_alloc_context3(codec);
*
* if (avcodec_open2(context, codec, opts) < 0)
*     exit(1);
* @endcode
*
* @param avctx The context to initialize.
* @param codec The codec to open this context for. If a non-NULL codec has been
*              previously passed to avcodec_alloc_context3() or
*              avcodec_get_context_defaults3() for this context, then this
*              parameter MUST be either NULL or equal to the previously passed
*              codec.
* @param options A dictionary filled with AVCodecContext and codec-private options.
*                On return this object will be filled with options that were not found.
*
* @return zero on success, a negative value on error
* @see avcodec_alloc_context3(), avcodec_find_decoder(), avcodec_find_encoder(),
*      av_dict_set(), av_opt_find().
*/
int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options);

/**
* Close a given AVCodecContext and free all the data associated with it
* (but not the AVCodecContext itself).
*
* Calling this function on an AVCodecContext that hasn't been opened will free
* the codec-specific data allocated in avcodec_alloc_context3() /
* avcodec_get_context_defaults3() with a non-NULL codec. Subsequent calls will
* do nothing.
*/
int avcodec_close(AVCodecContext *avctx);

/**
* Free all allocated data in the given subtitle struct.
*
* @param sub AVSubtitle to free.
*/
void avsubtitle_free(AVSubtitle *sub);

/**
* @}
*/

/**
* @addtogroup lavc_packet
* @{
*/

#if FF_API_DESTRUCT_PACKET
/**
* Default packet destructor.
* @deprecated use the AVBuffer API instead
*/
attribute_deprecated
void av_destruct_packet(AVPacket *pkt);
#endif

/**
* Initialize optional fields of a packet with default values.
*
* Note, this does not touch the data and size members, which have to be
* initialized separately.
*
* @param pkt packet
*/
void av_init_packet(AVPacket *pkt);

/**
* Allocate the payload of a packet and initialize its fields with
* default values.
*
* @param pkt packet
* @param size wanted payload size
* @return 0 if OK, AVERROR_xxx otherwise
*/
int av_new_packet(AVPacket *pkt, int size);

/**
* Reduce packet size, correctly zeroing padding
*
* @param pkt packet
* @param size new size
*/
void av_shrink_packet(AVPacket *pkt, int size);

/**
* Increase packet size, correctly zeroing padding
*
* @param pkt packet
* @param grow_by number of bytes by which to increase the size of the packet
*/
int av_grow_packet(AVPacket *pkt, int grow_by);

/**
* Initialize a reference-counted packet from av_malloc()ed data.
*
* @param pkt packet to be initialized. This function will set the data, size,
*        buf and destruct fields, all others are left untouched.
* @param data Data allocated by av_malloc() to be used as packet data. If this
*        function returns successfully, the data is owned by the underlying AVBuffer.
*        The caller may not access the data through other means.
* @param size size of data in bytes, without the padding. I.e. the full buffer
*        size is assumed to be size + FF_INPUT_BUFFER_PADDING_SIZE.
*
* @return 0 on success, a negative AVERROR on error
*/
int av_packet_from_data(AVPacket *pkt, uint8_t *data, int size);

/**
* @warning This is a hack - the packet memory allocation stuff is broken. The
* packet is allocated if it was not really allocated.
*/
int av_dup_packet(AVPacket *pkt);

/**
* Free a packet.
*
* @param pkt packet to free
*/
void av_free_packet(AVPacket *pkt);

/**
* Allocate new information of a packet.
*
* @param pkt packet
* @param type side information type
* @param size side information size
* @return pointer to fresh allocated data or NULL otherwise
*/
uint8_t* av_packet_new_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
                                int size);

/**
* Shrink the already allocated side data buffer
*
* @param pkt packet
* @param type side information type
* @param size new side information size
* @return 0 on success, < 0 on failure
*/
int av_packet_shrink_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
                              int size);

/**
* Get side information from packet.
*
* @param pkt packet
* @param type desired side information type
* @param size pointer for side information size to store (optional)
* @return pointer to data if present or NULL otherwise
*/
uint8_t* av_packet_get_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
                                int *size);

/**
* Convenience function to free all the side data stored.
* All the other fields stay untouched.
*
* @param pkt packet
*/
void av_packet_free_side_data(AVPacket *pkt);

/**
* Setup a new reference to the data described by a given packet
*
* If src is reference-counted, setup dst as a new reference to the
* buffer in src. Otherwise allocate a new buffer in dst and copy the
* data from src into it.
*
* All the other fields are copied from src.
*
* @see av_packet_unref
*
* @param dst Destination packet
* @param src Source packet
*
* @return 0 on success, a negative AVERROR on error.
*/
int av_packet_ref(AVPacket *dst, AVPacket *src);

/**
* Wipe the packet.
*
* Unreference the buffer referenced by the packet and reset the
* remaining packet fields to their default values.
*
* @param pkt The packet to be unreferenced.
*/
void av_packet_unref(AVPacket *pkt);

/**
* Move every field in src to dst and reset src.
*
* @see av_packet_unref
*
* @param src Source packet, will be reset
* @param dst Destination packet
*/
void av_packet_move_ref(AVPacket *dst, AVPacket *src);

/**
* Copy only "properties" fields from src to dst.
*
* Properties for the purpose of this function are all the fields
* beside those related to the packet data (buf, data, size)
*
* @param dst Destination packet
* @param src Source packet
*
* @return 0 on success AVERROR on failure.
*
*/
int av_packet_copy_props(AVPacket *dst, const AVPacket *src);

/**
* @}
*/

/**
* @addtogroup lavc_decoding
* @{
*/

/**
* Find a registered decoder with a matching codec ID.
*
* @param id AVCodecID of the requested decoder
* @return A decoder if one was found, NULL otherwise.
*/
AVCodec *avcodec_find_decoder(enum AVCodecID id);

/**
* Find a registered decoder with the specified name.
*
* @param name name of the requested decoder
* @return A decoder if one was found, NULL otherwise.
*/
AVCodec *avcodec_find_decoder_by_name(const char *name);

#if FF_API_GET_BUFFER
attribute_deprecated int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic);
attribute_deprecated void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic);
attribute_deprecated int avcodec_default_reget_buffer(AVCodecContext *s, AVFrame *pic);
#endif

/**
* The default callback for AVCodecContext.get_buffer2(). It is made public so
* it can be called by custom get_buffer2() implementations for decoders without
* CODEC_CAP_DR1 set.
*/
int avcodec_default_get_buffer2(AVCodecContext *s, AVFrame *frame, int flags);

#if FF_API_EMU_EDGE
/**
* Return the amount of padding in pixels which the get_buffer callback must
* provide around the edge of the image for codecs which do not have the
* CODEC_FLAG_EMU_EDGE flag.
*
* @return Required padding in pixels.
*
* @deprecated CODEC_FLAG_EMU_EDGE is deprecated, so this function is no longer
* needed
*/
attribute_deprecated
unsigned avcodec_get_edge_width(void);
#endif

/**
* Modify width and height values so that they will result in a memory
* buffer that is acceptable for the codec if you do not use any horizontal
* padding.
*
* May only be used if a codec with CODEC_CAP_DR1 has been opened.
*/
void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height);

/**
* Modify width and height values so that they will result in a memory
* buffer that is acceptable for the codec if you also ensure that all
* line sizes are a multiple of the respective linesize_align[i].
*
* May only be used if a codec with CODEC_CAP_DR1 has been opened.
*/
void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height,
                              int linesize_align[AV_NUM_DATA_POINTERS]);

/**
* Decode the audio frame of size avpkt->size from avpkt->data into frame.
*
* Some decoders may support multiple frames in a single AVPacket. Such
* decoders would then just decode the first frame and the return value would be
* less than the packet size. In this case, avcodec_decode_audio4 has to be
* called again with an AVPacket containing the remaining data in order to
* decode the second frame, etc...  Even if no frames are returned, the packet
* needs to be fed to the decoder with remaining data until it is completely
* consumed or an error occurs.
*
* Some decoders (those marked with CODEC_CAP_DELAY) have a delay between input
* and output. This means that for some packets they will not immediately
* produce decoded output and need to be flushed at the end of decoding to get
* all the decoded data. Flushing is done by calling this function with packets
* with avpkt->data set to NULL and avpkt->size set to 0 until it stops
* returning samples. It is safe to flush even those decoders that are not
* marked with CODEC_CAP_DELAY, then no samples will be returned.
*
* @warning The input buffer, avpkt->data must be FF_INPUT_BUFFER_PADDING_SIZE
*          larger than the actual read bytes because some optimized bitstream
*          readers read 32 or 64 bits at once and could read over the end.
*
* @param      avctx the codec context
* @param[out] frame The AVFrame in which to store decoded audio samples.
*                   The decoder will allocate a buffer for the decoded frame by
*                   calling the AVCodecContext.get_buffer2() callback.
*                   When AVCodecContext.refcounted_frames is set to 1, the frame is
*                   reference counted and the returned reference belongs to the
*                   caller. The caller must release the frame using av_frame_unref()
*                   when the frame is no longer needed. The caller may safely write
*                   to the frame if av_frame_is_writable() returns 1.
*                   When AVCodecContext.refcounted_frames is set to 0, the returned
*                   reference belongs to the decoder and is valid only until the
*                   next call to this function or until closing or flushing the
*                   decoder. The caller may not write to it.
* @param[out] got_frame_ptr Zero if no frame could be decoded, otherwise it is
*                           non-zero. Note that this field being set to zero
*                           does not mean that an error has occurred. For
*                           decoders with CODEC_CAP_DELAY set, no given decode
*                           call is guaranteed to produce a frame.
* @param[in]  avpkt The input AVPacket containing the input buffer.
*                   At least avpkt->data and avpkt->size should be set. Some
*                   decoders might also require additional fields to be set.
* @return A negative error code is returned if an error occurred during
*         decoding, otherwise the number of bytes consumed from the input
*         AVPacket is returned.
*/
int avcodec_decode_audio4(AVCodecContext *avctx, AVFrame *frame,
                         int *got_frame_ptr, AVPacket *avpkt);

/**
* Decode the video frame of size avpkt->size from avpkt->data into picture.
* Some decoders may support multiple frames in a single AVPacket, such
* decoders would then just decode the first frame.
*
* @warning The input buffer must be FF_INPUT_BUFFER_PADDING_SIZE larger than
* the actual read bytes because some optimized bitstream readers read 32 or 64
* bits at once and could read over the end.
*
* @warning The end of the input buffer buf should be set to 0 to ensure that
* no overreading happens for damaged MPEG streams.
*
* @note Codecs which have the CODEC_CAP_DELAY capability set have a delay
* between input and output, these need to be fed with avpkt->data=NULL,
* avpkt->size=0 at the end to return the remaining frames.
*
* @param avctx the codec context
* @param[out] picture The AVFrame in which the decoded video frame will be stored.
*             Use av_frame_alloc() to get an AVFrame. The codec will
*             allocate memory for the actual bitmap by calling the
*             AVCodecContext.get_buffer2() callback.
*             When AVCodecContext.refcounted_frames is set to 1, the frame is
*             reference counted and the returned reference belongs to the
*             caller. The caller must release the frame using av_frame_unref()
*             when the frame is no longer needed. The caller may safely write
*             to the frame if av_frame_is_writable() returns 1.
*             When AVCodecContext.refcounted_frames is set to 0, the returned
*             reference belongs to the decoder and is valid only until the
*             next call to this function or until closing or flushing the
*             decoder. The caller may not write to it.
*
* @param[in] avpkt The input AVpacket containing the input buffer.
*            You can create such packet with av_init_packet() and by then setting
*            data and size, some decoders might in addition need other fields like
*            flags&AV_PKT_FLAG_KEY. All decoders are designed to use the least
*            fields possible.
* @param[in,out] got_picture_ptr Zero if no frame could be decompressed, otherwise, it is nonzero.
* @return On error a negative value is returned, otherwise the number of bytes
* used or zero if no frame could be decompressed.
*/
int avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
                        int *got_picture_ptr,
                        AVPacket *avpkt);

/**
* Decode a subtitle message.
* Return a negative value on error, otherwise return the number of bytes used.
* If no subtitle could be decompressed, got_sub_ptr is zero.
* Otherwise, the subtitle is stored in *sub.
* Note that CODEC_CAP_DR1 is not available for subtitle codecs. This is for
* simplicity, because the performance difference is expect to be negligible
* and reusing a get_buffer written for video codecs would probably perform badly
* due to a potentially very different allocation pattern.
*
* @param avctx the codec context
* @param[out] sub The AVSubtitle in which the decoded subtitle will be stored, must be
                  freed with avsubtitle_free if *got_sub_ptr is set.
* @param[in,out] got_sub_ptr Zero if no subtitle could be decompressed, otherwise, it is nonzero.
* @param[in] avpkt The input AVPacket containing the input buffer.
*/
int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
                           int *got_sub_ptr,
                           AVPacket *avpkt);

/**
* @defgroup lavc_parsing Frame parsing
* @{
*/

enum AVPictureStructure {
   AV_PICTURE_STRUCTURE_UNKNOWN,      //< unknown
   AV_PICTURE_STRUCTURE_TOP_FIELD,    //< coded as top field
   AV_PICTURE_STRUCTURE_BOTTOM_FIELD, //< coded as bottom field
   AV_PICTURE_STRUCTURE_FRAME,        //< coded as frame
};

typedef struct AVCodecParserContext {
   void *priv_data;
   struct AVCodecParser *parser;
   int64_t frame_offset; /* offset of the current frame */
   int64_t cur_offset; /* current offset
                          (incremented by each av_parser_parse()) */
   int64_t next_frame_offset; /* offset of the next frame */
   /* video info */
   int pict_type; /* XXX: Put it back in AVCodecContext. */
   /**
    * This field is used for proper frame duration computation in lavf.
    * It signals, how much longer the frame duration of the current frame
    * is compared to normal frame duration.
    *
    * frame_duration = (1 + repeat_pict) * time_base
    *
    * It is used by codecs like H.264 to display telecined material.
    */
   int repeat_pict; /* XXX: Put it back in AVCodecContext. */
   int64_t pts;     /* pts of the current frame */
   int64_t dts;     /* dts of the current frame */

   /* private data */
   int64_t last_pts;
   int64_t last_dts;
   int fetch_timestamp;

#define AV_PARSER_PTS_NB 4
   int cur_frame_start_index;
   int64_t cur_frame_offset[AV_PARSER_PTS_NB];
   int64_t cur_frame_pts[AV_PARSER_PTS_NB];
   int64_t cur_frame_dts[AV_PARSER_PTS_NB];

   int flags;
#define PARSER_FLAG_COMPLETE_FRAMES           0x0001
#define PARSER_FLAG_ONCE                      0x0002
/// Set if the parser has a valid file offset
#define PARSER_FLAG_FETCHED_OFFSET            0x0004

   int64_t offset;      ///< byte offset from starting packet start
   int64_t cur_frame_end[AV_PARSER_PTS_NB];

   /**
    * Set by parser to 1 for key frames and 0 for non-key frames.
    * It is initialized to -1, so if the parser doesn't set this flag,
    * old-style fallback using AV_PICTURE_TYPE_I picture type as key frames
    * will be used.
    */
   int key_frame;

   /**
    * Time difference in stream time base units from the pts of this
    * packet to the point at which the output from the decoder has converged
    * independent from the availability of previous frames. That is, the
    * frames are virtually identical no matter if decoding started from
    * the very first frame or from this keyframe.
    * Is AV_NOPTS_VALUE if unknown.
    * This field is not the display duration of the current frame.
    * This field has no meaning if the packet does not have AV_PKT_FLAG_KEY
    * set.
    *
    * The purpose of this field is to allow seeking in streams that have no
    * keyframes in the conventional sense. It corresponds to the
    * recovery point SEI in H.264 and match_time_delta in NUT. It is also
    * essential for some types of subtitle streams to ensure that all
    * subtitles are correctly displayed after seeking.
    */
   int64_t convergence_duration;

   // Timestamp generation support:
   /**
    * Synchronization point for start of timestamp generation.
    *
    * Set to >0 for sync point, 0 for no sync point and <0 for undefined
    * (default).
    *
    * For example, this corresponds to presence of H.264 buffering period
    * SEI message.
    */
   int dts_sync_point;

   /**
    * Offset of the current timestamp against last timestamp sync point in
    * units of AVCodecContext.time_base.
    *
    * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
    * contain a valid timestamp offset.
    *
    * Note that the timestamp of sync point has usually a nonzero
    * dts_ref_dts_delta, which refers to the previous sync point. Offset of
    * the next frame after timestamp sync point will be usually 1.
    *
    * For example, this corresponds to H.264 cpb_removal_delay.
    */
   int dts_ref_dts_delta;

   /**
    * Presentation delay of current frame in units of AVCodecContext.time_base.
    *
    * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
    * contain valid non-negative timestamp delta (presentation time of a frame
    * must not lie in the past).
    *
    * This delay represents the difference between decoding and presentation
    * time of the frame.
    *
    * For example, this corresponds to H.264 dpb_output_delay.
    */
   int pts_dts_delta;

   /**
    * Position of the packet in file.
    *
    * Analogous to cur_frame_pts/dts
    */
   int64_t cur_frame_pos[AV_PARSER_PTS_NB];

   /**
    * Byte position of currently parsed frame in stream.
    */
   int64_t pos;

   /**
    * Previous frame byte position.
    */
   int64_t last_pos;

   /**
    * Duration of the current frame.
    * For audio, this is in units of 1 / AVCodecContext.sample_rate.
    * For all other types, this is in units of AVCodecContext.time_base.
    */
   int duration;

   enum AVFieldOrder field_order;

   /**
    * Indicate whether a picture is coded as a frame, top field or bottom field.
    *
    * For example, H.264 field_pic_flag equal to 0 corresponds to
    * AV_PICTURE_STRUCTURE_FRAME. An H.264 picture with field_pic_flag
    * equal to 1 and bottom_field_flag equal to 0 corresponds to
    * AV_PICTURE_STRUCTURE_TOP_FIELD.
    */
   enum AVPictureStructure picture_structure;

   /**
    * Picture number incremented in presentation or output order.
    * This field may be reinitialized at the first picture of a new sequence.
    *
    * For example, this corresponds to H.264 PicOrderCnt.
    */
   int output_picture_number;
} AVCodecParserContext;

typedef struct AVCodecParser {
   int codec_ids[5]; /* several codec IDs are permitted */
   int priv_data_size;
   int (*parser_init)(AVCodecParserContext *s);
   int (*parser_parse)(AVCodecParserContext *s,
                       AVCodecContext *avctx,
                       const uint8_t **poutbuf, int *poutbuf_size,
                       const uint8_t *buf, int buf_size);
   void (*parser_close)(AVCodecParserContext *s);
   int (*split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size);
   struct AVCodecParser *next;
} AVCodecParser;

AVCodecParser *av_parser_next(AVCodecParser *c);

void av_register_codec_parser(AVCodecParser *parser);
AVCodecParserContext *av_parser_init(int codec_id);

/**
* Parse a packet.
*
* @param s             parser context.
* @param avctx         codec context.
* @param poutbuf       set to pointer to parsed buffer or NULL if not yet finished.
* @param poutbuf_size  set to size of parsed buffer or zero if not yet finished.
* @param buf           input buffer.
* @param buf_size      input length, to signal EOF, this should be 0 (so that the last frame can be output).
* @param pts           input presentation timestamp.
* @param dts           input decoding timestamp.
* @param pos           input byte position in stream.
* @return the number of bytes of the input bitstream used.
*
* Example:
* @code
*   while(in_len){
*       len = av_parser_parse2(myparser, AVCodecContext, &data, &size,
*                                        in_data, in_len,
*                                        pts, dts, pos);
*       in_data += len;
*       in_len  -= len;
*
*       if(size)
*          decode_frame(data, size);
*   }
* @endcode
*/
int av_parser_parse2(AVCodecParserContext *s,
                    AVCodecContext *avctx,
                    uint8_t **poutbuf, int *poutbuf_size,
                    const uint8_t *buf, int buf_size,
                    int64_t pts, int64_t dts,
                    int64_t pos);

/**
* @return 0 if the output buffer is a subset of the input, 1 if it is allocated and must be freed
* @deprecated use AVBitstreamFilter
*/
int av_parser_change(AVCodecParserContext *s,
                    AVCodecContext *avctx,
                    uint8_t **poutbuf, int *poutbuf_size,
                    const uint8_t *buf, int buf_size, int keyframe);
void av_parser_close(AVCodecParserContext *s);

/**
* @}
* @}
*/

/**
* @addtogroup lavc_encoding
* @{
*/

/**
* Find a registered encoder with a matching codec ID.
*
* @param id AVCodecID of the requested encoder
* @return An encoder if one was found, NULL otherwise.
*/
AVCodec *avcodec_find_encoder(enum AVCodecID id);

/**
* Find a registered encoder with the specified name.
*
* @param name name of the requested encoder
* @return An encoder if one was found, NULL otherwise.
*/
AVCodec *avcodec_find_encoder_by_name(const char *name);

/**
* Encode a frame of audio.
*
* Takes input samples from frame and writes the next output packet, if
* available, to avpkt. The output packet does not necessarily contain data for
* the most recent frame, as encoders can delay, split, and combine input frames
* internally as needed.
*
* @param avctx     codec context
* @param avpkt     output AVPacket.
*                  The user can supply an output buffer by setting
*                  avpkt->data and avpkt->size prior to calling the
*                  function, but if the size of the user-provided data is not
*                  large enough, encoding will fail. All other AVPacket fields
*                  will be reset by the encoder using av_init_packet(). If
*                  avpkt->data is NULL, the encoder will allocate it.
*                  The encoder will set avpkt->size to the size of the
*                  output packet.
*
*                  If this function fails or produces no output, avpkt will be
*                  freed using av_free_packet() (i.e. avpkt->destruct will be
*                  called to free the user supplied buffer).
* @param[in] frame AVFrame containing the raw audio data to be encoded.
*                  May be NULL when flushing an encoder that has the
*                  CODEC_CAP_DELAY capability set.
*                  If CODEC_CAP_VARIABLE_FRAME_SIZE is set, then each frame
*                  can have any number of samples.
*                  If it is not set, frame->nb_samples must be equal to
*                  avctx->frame_size for all frames except the last.
*                  The final frame may be smaller than avctx->frame_size.
* @param[out] got_packet_ptr This field is set to 1 by libavcodec if the
*                            output packet is non-empty, and to 0 if it is
*                            empty. If the function returns an error, the
*                            packet can be assumed to be invalid, and the
*                            value of got_packet_ptr is undefined and should
*                            not be used.
* @return          0 on success, negative error code on failure
*/
int avcodec_encode_audio2(AVCodecContext *avctx, AVPacket *avpkt,
                         const AVFrame *frame, int *got_packet_ptr);

/**
* Encode a frame of video.
*
* Takes input raw video data from frame and writes the next output packet, if
* available, to avpkt. The output packet does not necessarily contain data for
* the most recent frame, as encoders can delay and reorder input frames
* internally as needed.
*
* @param avctx     codec context
* @param avpkt     output AVPacket.
*                  The user can supply an output buffer by setting
*                  avpkt->data and avpkt->size prior to calling the
*                  function, but if the size of the user-provided data is not
*                  large enough, encoding will fail. All other AVPacket fields
*                  will be reset by the encoder using av_init_packet(). If
*                  avpkt->data is NULL, the encoder will allocate it.
*                  The encoder will set avpkt->size to the size of the
*                  output packet. The returned data (if any) belongs to the
*                  caller, he is responsible for freeing it.
*
*                  If this function fails or produces no output, avpkt will be
*                  freed using av_free_packet() (i.e. avpkt->destruct will be
*                  called to free the user supplied buffer).
* @param[in] frame AVFrame containing the raw video data to be encoded.
*                  May be NULL when flushing an encoder that has the
*                  CODEC_CAP_DELAY capability set.
* @param[out] got_packet_ptr This field is set to 1 by libavcodec if the
*                            output packet is non-empty, and to 0 if it is
*                            empty. If the function returns an error, the
*                            packet can be assumed to be invalid, and the
*                            value of got_packet_ptr is undefined and should
*                            not be used.
* @return          0 on success, negative error code on failure
*/
int avcodec_encode_video2(AVCodecContext *avctx, AVPacket *avpkt,
                         const AVFrame *frame, int *got_packet_ptr);

int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
                           const AVSubtitle *sub);


/**
* @}
*/

/**
* @addtogroup lavc_picture
* @{
*/

/**
* Allocate memory for a picture.  Call avpicture_free() to free it.
*
* @see avpicture_fill()
*
* @param picture the picture to be filled in
* @param pix_fmt the format of the picture
* @param width the width of the picture
* @param height the height of the picture
* @return zero if successful, a negative value if not
*/
int avpicture_alloc(AVPicture *picture, enum AVPixelFormat pix_fmt, int width, int height);

/**
* Free a picture previously allocated by avpicture_alloc().
* The data buffer used by the AVPicture is freed, but the AVPicture structure
* itself is not.
*
* @param picture the AVPicture to be freed
*/
void avpicture_free(AVPicture *picture);

/**
* Fill in the AVPicture fields.
* The fields of the given AVPicture are filled in by using the 'ptr' address
* which points to the image data buffer. Depending on the specified picture
* format, one or multiple image data pointers and line sizes will be set.
* If a planar format is specified, several pointers will be set pointing to
* the different picture planes and the line sizes of the different planes
* will be stored in the lines_sizes array.
* Call with ptr == NULL to get the required size for the ptr buffer.
*
* To allocate the buffer and fill in the AVPicture fields in one call,
* use avpicture_alloc().
*
* @param picture AVPicture whose fields are to be filled in
* @param ptr Buffer which will contain or contains the actual image data
* @param pix_fmt The format in which the picture data is stored.
* @param width the width of the image in pixels
* @param height the height of the image in pixels
* @return size of the image data in bytes
*/
int avpicture_fill(AVPicture *picture, uint8_t *ptr,
                  enum AVPixelFormat pix_fmt, int width, int height);

/**
* Copy pixel data from an AVPicture into a buffer.
* The data is stored compactly, without any gaps for alignment or padding
* which may be applied by avpicture_fill().
*
* @see avpicture_get_size()
*
* @param[in] src AVPicture containing image data
* @param[in] pix_fmt The format in which the picture data is stored.
* @param[in] width the width of the image in pixels.
* @param[in] height the height of the image in pixels.
* @param[out] dest A buffer into which picture data will be copied.
* @param[in] dest_size The size of 'dest'.
* @return The number of bytes written to dest, or a negative value (error code) on error.
*/
int avpicture_layout(const AVPicture* src, enum AVPixelFormat pix_fmt,
                    int width, int height,
                    unsigned char *dest, int dest_size);

/**
* Calculate the size in bytes that a picture of the given width and height
* would occupy if stored in the given picture format.
* Note that this returns the size of a compact representation as generated
* by avpicture_layout(), which can be smaller than the size required for e.g.
* avpicture_fill().
*
* @param pix_fmt the given picture format
* @param width the width of the image
* @param height the height of the image
* @return Image data size in bytes or -1 on error (e.g. too large dimensions).
*/
int avpicture_get_size(enum AVPixelFormat pix_fmt, int width, int height);

#if FF_API_DEINTERLACE
/**
*  deinterlace - if not supported return -1
*
* @deprecated - use yadif (in libavfilter) instead
*/
attribute_deprecated
int avpicture_deinterlace(AVPicture *dst, const AVPicture *src,
                         enum AVPixelFormat pix_fmt, int width, int height);
#endif
/**
* Copy image src to dst. Wraps av_picture_data_copy() above.
*/
void av_picture_copy(AVPicture *dst, const AVPicture *src,
                    enum AVPixelFormat pix_fmt, int width, int height);

/**
* Crop image top and left side.
*/
int av_picture_crop(AVPicture *dst, const AVPicture *src,
                   enum AVPixelFormat pix_fmt, int top_band, int left_band);

/**
* Pad image.
*/
int av_picture_pad(AVPicture *dst, const AVPicture *src, int height, int width, enum AVPixelFormat pix_fmt,
           int padtop, int padbottom, int padleft, int padright, int *color);

/**
* @}
*/

/**
* @defgroup lavc_misc Utility functions
* @ingroup libavc
*
* Miscellaneous utility functions related to both encoding and decoding
* (or neither).
* @{
*/

/**
* @defgroup lavc_misc_pixfmt Pixel formats
*
* Functions for working with pixel formats.
* @{
*/

/**
* @deprecated Use av_pix_fmt_get_chroma_sub_sample
*/

void attribute_deprecated avcodec_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, int *h_shift, int *v_shift);

/**
* Return a value representing the fourCC code associated to the
* pixel format pix_fmt, or 0 if no associated fourCC code can be
* found.
*/
unsigned int avcodec_pix_fmt_to_codec_tag(enum AVPixelFormat pix_fmt);

#define FF_LOSS_RESOLUTION  0x0001 /**< loss due to resolution change */
#define FF_LOSS_DEPTH       0x0002 /**< loss due to color depth change */
#define FF_LOSS_COLORSPACE  0x0004 /**< loss due to color space conversion */
#define FF_LOSS_ALPHA       0x0008 /**< loss of alpha bits */
#define FF_LOSS_COLORQUANT  0x0010 /**< loss due to color quantization */
#define FF_LOSS_CHROMA      0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */

/**
* Compute what kind of losses will occur when converting from one specific
* pixel format to another.
* When converting from one pixel format to another, information loss may occur.
* For example, when converting from RGB24 to GRAY, the color information will
* be lost. Similarly, other losses occur when converting from some formats to
* other formats. These losses can involve loss of chroma, but also loss of
* resolution, loss of color depth, loss due to the color space conversion, loss
* of the alpha bits or loss due to color quantization.
* avcodec_get_fix_fmt_loss() informs you about the various types of losses
* which will occur when converting from one pixel format to another.
*
* @param[in] dst_pix_fmt destination pixel format
* @param[in] src_pix_fmt source pixel format
* @param[in] has_alpha Whether the source pixel format alpha channel is used.
* @return Combination of flags informing you what kind of losses will occur.
*/
int avcodec_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt, enum AVPixelFormat src_pix_fmt,
                            int has_alpha);

/**
* Find the best pixel format to convert to given a certain source pixel
* format.  When converting from one pixel format to another, information loss
* may occur.  For example, when converting from RGB24 to GRAY, the color
* information will be lost. Similarly, other losses occur when converting from
* some formats to other formats. avcodec_find_best_pix_fmt2() searches which of
* the given pixel formats should be used to suffer the least amount of loss.
* The pixel formats from which it chooses one, are determined by the
* pix_fmt_list parameter.
*
*
* @param[in] pix_fmt_list AV_PIX_FMT_NONE terminated array of pixel formats to choose from
* @param[in] src_pix_fmt source pixel format
* @param[in] has_alpha Whether the source pixel format alpha channel is used.
* @param[out] loss_ptr Combination of flags informing you what kind of losses will occur.
* @return The best pixel format to convert to or -1 if none was found.
*/
enum AVPixelFormat avcodec_find_best_pix_fmt2(enum AVPixelFormat *pix_fmt_list,
                                             enum AVPixelFormat src_pix_fmt,
                                             int has_alpha, int *loss_ptr);

enum AVPixelFormat avcodec_default_get_format(struct AVCodecContext *s, const enum AVPixelFormat * fmt);

/**
* @}
*/

#if FF_API_SET_DIMENSIONS
/**
* @deprecated this function is not supposed to be used from outside of lavc
*/
attribute_deprecated
void avcodec_set_dimensions(AVCodecContext *s, int width, int height);
#endif

/**
* Put a string representing the codec tag codec_tag in buf.
*
* @param buf       buffer to place codec tag in
* @param buf_size size in bytes of buf
* @param codec_tag codec tag to assign
* @return the length of the string that would have been generated if
* enough space had been available, excluding the trailing null
*/
size_t av_get_codec_tag_string(char *buf, size_t buf_size, unsigned int codec_tag);

void avcodec_string(char *buf, int buf_size, AVCodecContext *enc, int encode);

/**
* Return a name for the specified profile, if available.
*
* @param codec the codec that is searched for the given profile
* @param profile the profile value for which a name is requested
* @return A name for the profile if found, NULL otherwise.
*/
const char *av_get_profile_name(const AVCodec *codec, int profile);

int avcodec_default_execute(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2),void *arg, int *ret, int count, int size);
int avcodec_default_execute2(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2, int, int),void *arg, int *ret, int count);
//FIXME func typedef

/**
* Fill audio frame data and linesize.
* AVFrame extended_data channel pointers are allocated if necessary for
* planar audio.
*
* @param frame       the AVFrame
*                    frame->nb_samples must be set prior to calling the
*                    function. This function fills in frame->data,
*                    frame->extended_data, frame->linesize[0].
* @param nb_channels channel count
* @param sample_fmt  sample format
* @param buf         buffer to use for frame data
* @param buf_size    size of buffer
* @param align       plane size sample alignment (0 = default)
* @return            0 on success, negative error code on failure
*/
int avcodec_fill_audio_frame(AVFrame *frame, int nb_channels,
                            enum AVSampleFormat sample_fmt, const uint8_t *buf,
                            int buf_size, int align);

/**
* Reset the internal decoder state / flush internal buffers. Should be called
* e.g. when seeking or when switching to a different stream.
*
* @note when refcounted frames are not used (i.e. avctx->refcounted_frames is 0),
* this invalidates the frames previously returned from the decoder. When
* refcounted frames are used, the decoder just releases any references it might
* keep internally, but the caller's reference remains valid.
*/
void avcodec_flush_buffers(AVCodecContext *avctx);

/**
* Return codec bits per sample.
*
* @param[in] codec_id the codec
* @return Number of bits per sample or zero if unknown for the given codec.
*/
int av_get_bits_per_sample(enum AVCodecID codec_id);

/**
* Return codec bits per sample.
* Only return non-zero if the bits per sample is exactly correct, not an
* approximation.
*
* @param[in] codec_id the codec
* @return Number of bits per sample or zero if unknown for the given codec.
*/
int av_get_exact_bits_per_sample(enum AVCodecID codec_id);

/**
* Return audio frame duration.
*
* @param avctx        codec context
* @param frame_bytes  size of the frame, or 0 if unknown
* @return             frame duration, in samples, if known. 0 if not able to
*                     determine.
*/
int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes);


typedef struct AVBitStreamFilterContext {
   void *priv_data;
   struct AVBitStreamFilter *filter;
   AVCodecParserContext *parser;
   struct AVBitStreamFilterContext *next;
} AVBitStreamFilterContext;


typedef struct AVBitStreamFilter {
   const char *name;
   int priv_data_size;
   int (*filter)(AVBitStreamFilterContext *bsfc,
                 AVCodecContext *avctx, const char *args,
                 uint8_t **poutbuf, int *poutbuf_size,
                 const uint8_t *buf, int buf_size, int keyframe);
   void (*close)(AVBitStreamFilterContext *bsfc);
   struct AVBitStreamFilter *next;
} AVBitStreamFilter;

void av_register_bitstream_filter(AVBitStreamFilter *bsf);
AVBitStreamFilterContext *av_bitstream_filter_init(const char *name);
int av_bitstream_filter_filter(AVBitStreamFilterContext *bsfc,
                              AVCodecContext *avctx, const char *args,
                              uint8_t **poutbuf, int *poutbuf_size,
                              const uint8_t *buf, int buf_size, int keyframe);
void av_bitstream_filter_close(AVBitStreamFilterContext *bsf);

AVBitStreamFilter *av_bitstream_filter_next(AVBitStreamFilter *f);

/* memory */

/**
* Allocate a buffer with padding, reusing the given one if large enough.
*
* Same behaviour av_fast_malloc but the buffer has additional
* FF_INPUT_PADDING_SIZE at the end which will always memset to 0.
*
*/
void av_fast_padded_malloc(void *ptr, unsigned int *size, size_t min_size);

/**
* Encode extradata length to a buffer. Used by xiph codecs.
*
* @param s buffer to write to; must be at least (v/255+1) bytes long
* @param v size of extradata in bytes
* @return number of bytes written to the buffer.
*/
unsigned int av_xiphlacing(unsigned char *s, unsigned int v);

#if FF_API_MISSING_SAMPLE
/**
* Log a generic warning message about a missing feature. This function is
* intended to be used internally by Libav (libavcodec, libavformat, etc.)
* only, and would normally not be used by applications.
* @param[in] avc a pointer to an arbitrary struct of which the first field is
* a pointer to an AVClass struct
* @param[in] feature string containing the name of the missing feature
* @param[in] want_sample indicates if samples are wanted which exhibit this feature.
* If want_sample is non-zero, additional verbage will be added to the log
* message which tells the user how to report samples to the development
* mailing list.
* @deprecated Use avpriv_report_missing_feature() instead.
*/
attribute_deprecated
void av_log_missing_feature(void *avc, const char *feature, int want_sample);

/**
* Log a generic warning message asking for a sample. This function is
* intended to be used internally by Libav (libavcodec, libavformat, etc.)
* only, and would normally not be used by applications.
* @param[in] avc a pointer to an arbitrary struct of which the first field is
* a pointer to an AVClass struct
* @param[in] msg string containing an optional message, or NULL if no message
* @deprecated Use avpriv_request_sample() instead.
*/
attribute_deprecated
void av_log_ask_for_sample(void *avc, const char *msg, ...) av_printf_format(2, 3);
#endif /* FF_API_MISSING_SAMPLE */

/**
* Register the hardware accelerator hwaccel.
*/
void av_register_hwaccel(AVHWAccel *hwaccel);

/**
* If hwaccel is NULL, returns the first registered hardware accelerator,
* if hwaccel is non-NULL, returns the next registered hardware accelerator
* after hwaccel, or NULL if hwaccel is the last one.
*/
AVHWAccel *av_hwaccel_next(AVHWAccel *hwaccel);


/**
* Lock operation used by lockmgr
*/
enum AVLockOp {
 AV_LOCK_CREATE,  ///< Create a mutex
 AV_LOCK_OBTAIN,  ///< Lock the mutex
 AV_LOCK_RELEASE, ///< Unlock the mutex
 AV_LOCK_DESTROY, ///< Free mutex resources
};

/**
* Register a user provided lock manager supporting the operations
* specified by AVLockOp. mutex points to a (void *) where the
* lockmgr should store/get a pointer to a user allocated mutex. It's
* NULL upon AV_LOCK_CREATE and != NULL for all other ops.
*
* @param cb User defined callback. Note: Libav may invoke calls to this
*           callback during the call to av_lockmgr_register().
*           Thus, the application must be prepared to handle that.
*           If cb is set to NULL the lockmgr will be unregistered.
*           Also note that during unregistration the previously registered
*           lockmgr callback may also be invoked.
*/
int av_lockmgr_register(int (*cb)(void **mutex, enum AVLockOp op));

/**
* Get the type of the given codec.
*/
enum AVMediaType avcodec_get_type(enum AVCodecID codec_id);

/**
* @return a positive value if s is open (i.e. avcodec_open2() was called on it
* with no corresponding avcodec_close()), 0 otherwise.
*/
int avcodec_is_open(AVCodecContext *s);

/**
* @return a non-zero number if codec is an encoder, zero otherwise
*/
int av_codec_is_encoder(const AVCodec *codec);

/**
* @return a non-zero number if codec is a decoder, zero otherwise
*/
int av_codec_is_decoder(const AVCodec *codec);

/**
* @return descriptor for given codec ID or NULL if no descriptor exists.
*/
const AVCodecDescriptor *avcodec_descriptor_get(enum AVCodecID id);

/**
* Iterate over all codec descriptors known to libavcodec.
*
* @param prev previous descriptor. NULL to get the first descriptor.
*
* @return next descriptor or NULL after the last descriptor
*/
const AVCodecDescriptor *avcodec_descriptor_next(const AVCodecDescriptor *prev);

/**
* @return codec descriptor with the given name or NULL if no such descriptor
*         exists.
*/
const AVCodecDescriptor *avcodec_descriptor_get_by_name(const char *name);

/**
* @}
*/

#endif /* AVCODEC_AVCODEC_H */