tor-browser

frame.h (31055B)

---

/*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

/**
* @file
* @ingroup lavu_frame
* reference-counted frame API
*/

#ifndef AVUTIL_FRAME_H
#define AVUTIL_FRAME_H

#include <stddef.h>
#include <stdint.h>

#include "avutil.h"
#include "buffer.h"
#include "channel_layout.h"
#include "dict.h"
#include "rational.h"
#include "samplefmt.h"
#include "pixfmt.h"
#include "version.h"

/**
* @defgroup lavu_frame AVFrame
* @ingroup lavu_data
*
* @{
* AVFrame is an abstraction for reference-counted raw multimedia data.
*/

enum AVFrameSideDataType {
 /**
  * The data is the AVPanScan struct defined in libavcodec.
  */
 AV_FRAME_DATA_PANSCAN,
 /**
  * ATSC A53 Part 4 Closed Captions.
  * A53 CC bitstream is stored as uint8_t in AVFrameSideData.data.
  * The number of bytes of CC data is AVFrameSideData.size.
  */
 AV_FRAME_DATA_A53_CC,
 /**
  * Stereoscopic 3d metadata.
  * The data is the AVStereo3D struct defined in libavutil/stereo3d.h.
  */
 AV_FRAME_DATA_STEREO3D,
 /**
  * The data is the AVMatrixEncoding enum defined in
  * libavutil/channel_layout.h.
  */
 AV_FRAME_DATA_MATRIXENCODING,
 /**
  * Metadata relevant to a downmix procedure.
  * The data is the AVDownmixInfo struct defined in libavutil/downmix_info.h.
  */
 AV_FRAME_DATA_DOWNMIX_INFO,
 /**
  * ReplayGain information in the form of the AVReplayGain struct.
  */
 AV_FRAME_DATA_REPLAYGAIN,
 /**
  * This side data contains a 3x3 transformation matrix describing an affine
  * transformation that needs to be applied to the frame for correct
  * presentation.
  *
  * See libavutil/display.h for a detailed description of the data.
  */
 AV_FRAME_DATA_DISPLAYMATRIX,
 /**
  * Active Format Description data consisting of a single byte as specified
  * in ETSI TS 101 154 using AVActiveFormatDescription enum.
  */
 AV_FRAME_DATA_AFD,
 /**
  * Motion vectors exported by some codecs (on demand through the export_mvs
  * flag set in the libavcodec AVCodecContext flags2 option).
  * The data is the AVMotionVector struct defined in
  * libavutil/motion_vector.h.
  */
 AV_FRAME_DATA_MOTION_VECTORS,
 /**
  * Recommmends skipping the specified number of samples. This is exported
  * only if the "skip_manual" AVOption is set in libavcodec.
  * This has the same format as AV_PKT_DATA_SKIP_SAMPLES.
  * @code
  * u32le number of samples to skip from start of this packet
  * u32le number of samples to skip from end of this packet
  * u8    reason for start skip
  * u8    reason for end   skip (0=padding silence, 1=convergence)
  * @endcode
  */
 AV_FRAME_DATA_SKIP_SAMPLES,
 /**
  * This side data must be associated with an audio frame and corresponds to
  * enum AVAudioServiceType defined in avcodec.h.
  */
 AV_FRAME_DATA_AUDIO_SERVICE_TYPE,
 /**
  * Mastering display metadata associated with a video frame. The payload is
  * an AVMasteringDisplayMetadata type and contains information about the
  * mastering display color volume.
  */
 AV_FRAME_DATA_MASTERING_DISPLAY_METADATA,
 /**
  * The GOP timecode in 25 bit timecode format. Data format is 64-bit integer.
  * This is set on the first frame of a GOP that has a temporal reference of 0.
  */
 AV_FRAME_DATA_GOP_TIMECODE,

 /**
  * The data represents the AVSphericalMapping structure defined in
  * libavutil/spherical.h.
  */
 AV_FRAME_DATA_SPHERICAL,

 /**
  * Content light level (based on CTA-861.3). This payload contains data in
  * the form of the AVContentLightMetadata struct.
  */
 AV_FRAME_DATA_CONTENT_LIGHT_LEVEL,

 /**
  * The data contains an ICC profile as an opaque octet buffer following the
  * format described by ISO 15076-1 with an optional name defined in the
  * metadata key entry "name".
  */
 AV_FRAME_DATA_ICC_PROFILE,

 /**
  * Timecode which conforms to SMPTE ST 12-1. The data is an array of 4
  * uint32_t where the first uint32_t describes how many (1-3) of the other
  * timecodes are used. The timecode format is described in the documentation
  * of av_timecode_get_smpte_from_framenum() function in libavutil/timecode.h.
  */
 AV_FRAME_DATA_S12M_TIMECODE,

 /**
  * HDR dynamic metadata associated with a video frame. The payload is
  * an AVDynamicHDRPlus type and contains information for color
  * volume transform - application 4 of SMPTE 2094-40:2016 standard.
  */
 AV_FRAME_DATA_DYNAMIC_HDR_PLUS,

 /**
  * Regions Of Interest, the data is an array of AVRegionOfInterest type, the
  * number of array element is implied by AVFrameSideData.size /
  * AVRegionOfInterest.self_size.
  */
 AV_FRAME_DATA_REGIONS_OF_INTEREST,

 /**
  * Encoding parameters for a video frame, as described by AVVideoEncParams.
  */
 AV_FRAME_DATA_VIDEO_ENC_PARAMS,

 /**
  * User data unregistered metadata associated with a video frame.
  * This is the H.26[45] UDU SEI message, and shouldn't be used for any other
  * purpose The data is stored as uint8_t in AVFrameSideData.data which is 16
  * bytes of uuid_iso_iec_11578 followed by AVFrameSideData.size - 16 bytes of
  * user_data_payload_byte.
  */
 AV_FRAME_DATA_SEI_UNREGISTERED,

 /**
  * Film grain parameters for a frame, described by AVFilmGrainParams.
  * Must be present for every frame which should have film grain applied.
  */
 AV_FRAME_DATA_FILM_GRAIN_PARAMS,

 /**
  * Bounding boxes for object detection and classification,
  * as described by AVDetectionBBoxHeader.
  */
 AV_FRAME_DATA_DETECTION_BBOXES,

 /**
  * Dolby Vision RPU raw data, suitable for passing to x265
  * or other libraries. Array of uint8_t, with NAL emulation
  * bytes intact.
  */
 AV_FRAME_DATA_DOVI_RPU_BUFFER,

 /**
  * Parsed Dolby Vision metadata, suitable for passing to a software
  * implementation. The payload is the AVDOVIMetadata struct defined in
  * libavutil/dovi_meta.h.
  */
 AV_FRAME_DATA_DOVI_METADATA,

 /**
  * HDR Vivid dynamic metadata associated with a video frame. The payload is
  * an AVDynamicHDRVivid type and contains information for color
  * volume transform - CUVA 005.1-2021.
  */
 AV_FRAME_DATA_DYNAMIC_HDR_VIVID,

 /**
  * Ambient viewing environment metadata, as defined by H.274.
  */
 AV_FRAME_DATA_AMBIENT_VIEWING_ENVIRONMENT,
};

enum AVActiveFormatDescription {
 AV_AFD_SAME = 8,
 AV_AFD_4_3 = 9,
 AV_AFD_16_9 = 10,
 AV_AFD_14_9 = 11,
 AV_AFD_4_3_SP_14_9 = 13,
 AV_AFD_16_9_SP_14_9 = 14,
 AV_AFD_SP_4_3 = 15,
};

/**
* Structure to hold side data for an AVFrame.
*
* sizeof(AVFrameSideData) is not a part of the public ABI, so new fields may be
* added to the end with a minor bump.
*/
typedef struct AVFrameSideData {
 enum AVFrameSideDataType type;
 uint8_t* data;
 size_t size;
 AVDictionary* metadata;
 AVBufferRef* buf;
} AVFrameSideData;

/**
* Structure describing a single Region Of Interest.
*
* When multiple regions are defined in a single side-data block, they
* should be ordered from most to least important - some encoders are only
* capable of supporting a limited number of distinct regions, so will have
* to truncate the list.
*
* When overlapping regions are defined, the first region containing a given
* area of the frame applies.
*/
typedef struct AVRegionOfInterest {
 /**
  * Must be set to the size of this data structure (that is,
  * sizeof(AVRegionOfInterest)).
  */
 uint32_t self_size;
 /**
  * Distance in pixels from the top edge of the frame to the top and
  * bottom edges and from the left edge of the frame to the left and
  * right edges of the rectangle defining this region of interest.
  *
  * The constraints on a region are encoder dependent, so the region
  * actually affected may be slightly larger for alignment or other
  * reasons.
  */
 int top;
 int bottom;
 int left;
 int right;
 /**
  * Quantisation offset.
  *
  * Must be in the range -1 to +1.  A value of zero indicates no quality
  * change.  A negative value asks for better quality (less quantisation),
  * while a positive value asks for worse quality (greater quantisation).
  *
  * The range is calibrated so that the extreme values indicate the
  * largest possible offset - if the rest of the frame is encoded with the
  * worst possible quality, an offset of -1 indicates that this region
  * should be encoded with the best possible quality anyway.  Intermediate
  * values are then interpolated in some codec-dependent way.
  *
  * For example, in 10-bit H.264 the quantisation parameter varies between
  * -12 and 51.  A typical qoffset value of -1/10 therefore indicates that
  * this region should be encoded with a QP around one-tenth of the full
  * range better than the rest of the frame.  So, if most of the frame
  * were to be encoded with a QP of around 30, this region would get a QP
  * of around 24 (an offset of approximately -1/10 * (51 - -12) = -6.3).
  * An extreme value of -1 would indicate that this region should be
  * encoded with the best possible quality regardless of the treatment of
  * the rest of the frame - that is, should be encoded at a QP of -12.
  */
 AVRational qoffset;
} AVRegionOfInterest;

/**
* This structure describes decoded (raw) audio or video data.
*
* AVFrame must be allocated using av_frame_alloc(). Note that this only
* allocates the AVFrame itself, the buffers for the data must be managed
* through other means (see below).
* AVFrame must be freed with av_frame_free().
*
* AVFrame is typically allocated once and then reused multiple times to hold
* different data (e.g. a single AVFrame to hold frames received from a
* decoder). In such a case, av_frame_unref() will free any references held by
* the frame and reset it to its original clean state before it
* is reused again.
*
* The data described by an AVFrame is usually reference counted through the
* AVBuffer API. The underlying buffer references are stored in AVFrame.buf /
* AVFrame.extended_buf. An AVFrame is considered to be reference counted if at
* least one reference is set, i.e. if AVFrame.buf[0] != NULL. In such a case,
* every single data plane must be contained in one of the buffers in
* AVFrame.buf or AVFrame.extended_buf.
* There may be a single buffer for all the data, or one separate buffer for
* each plane, or anything in between.
*
* sizeof(AVFrame) is not a part of the public ABI, so new fields may be added
* to the end with a minor bump.
*
* Fields can be accessed through AVOptions, the name string used, matches the
* C structure field name for fields accessible through AVOptions. The AVClass
* for AVFrame can be obtained from avcodec_get_frame_class()
*/
typedef struct AVFrame {
#define AV_NUM_DATA_POINTERS 8
 /**
  * pointer to the picture/channel planes.
  * This might be different from the first allocated byte. For video,
  * it could even point to the end of the image data.
  *
  * All pointers in data and extended_data must point into one of the
  * AVBufferRef in buf or extended_buf.
  *
  * Some decoders access areas outside 0,0 - width,height, please
  * see avcodec_align_dimensions2(). Some filters and swscale can read
  * up to 16 bytes beyond the planes, if these filters are to be used,
  * then 16 extra bytes must be allocated.
  *
  * NOTE: Pointers not needed by the format MUST be set to NULL.
  *
  * @attention In case of video, the data[] pointers can point to the
  * end of image data in order to reverse line order, when used in
  * combination with negative values in the linesize[] array.
  */
 uint8_t* data[AV_NUM_DATA_POINTERS];

 /**
  * For video, a positive or negative value, which is typically indicating
  * the size in bytes of each picture line, but it can also be:
  * - the negative byte size of lines for vertical flipping
  *   (with data[n] pointing to the end of the data
  * - a positive or negative multiple of the byte size as for accessing
  *   even and odd fields of a frame (possibly flipped)
  *
  * For audio, only linesize[0] may be set. For planar audio, each channel
  * plane must be the same size.
  *
  * For video the linesizes should be multiples of the CPUs alignment
  * preference, this is 16 or 32 for modern desktop CPUs.
  * Some code requires such alignment other code can be slower without
  * correct alignment, for yet other it makes no difference.
  *
  * @note The linesize may be larger than the size of usable data -- there
  * may be extra padding present for performance reasons.
  *
  * @attention In case of video, line size values can be negative to achieve
  * a vertically inverted iteration over image lines.
  */
 int linesize[AV_NUM_DATA_POINTERS];

 /**
  * pointers to the data planes/channels.
  *
  * For video, this should simply point to data[].
  *
  * For planar audio, each channel has a separate data pointer, and
  * linesize[0] contains the size of each channel buffer.
  * For packed audio, there is just one data pointer, and linesize[0]
  * contains the total size of the buffer for all channels.
  *
  * Note: Both data and extended_data should always be set in a valid frame,
  * but for planar audio with more channels that can fit in data,
  * extended_data must be used in order to access all channels.
  */
 uint8_t** extended_data;

 /**
  * @name Video dimensions
  * Video frames only. The coded dimensions (in pixels) of the video frame,
  * i.e. the size of the rectangle that contains some well-defined values.
  *
  * @note The part of the frame intended for display/presentation is further
  * restricted by the @ref cropping "Cropping rectangle".
  * @{
  */
 int width, height;
 /**
  * @}
  */

 /**
  * number of audio samples (per channel) described by this frame
  */
 int nb_samples;

 /**
  * format of the frame, -1 if unknown or unset
  * Values correspond to enum AVPixelFormat for video frames,
  * enum AVSampleFormat for audio)
  */
 int format;

 /**
  * 1 -> keyframe, 0-> not
  */
 int key_frame;

 /**
  * Picture type of the frame.
  */
 enum AVPictureType pict_type;

 /**
  * Sample aspect ratio for the video frame, 0/1 if unknown/unspecified.
  */
 AVRational sample_aspect_ratio;

 /**
  * Presentation timestamp in time_base units (time when frame should be shown
  * to user).
  */
 int64_t pts;

 /**
  * DTS copied from the AVPacket that triggered returning this frame. (if frame
  * threading isn't used) This is also the Presentation time of this AVFrame
  * calculated from only AVPacket.dts values without pts values.
  */
 int64_t pkt_dts;

 /**
  * Time base for the timestamps in this frame.
  * In the future, this field may be set on frames output by decoders or
  * filters, but its value will be by default ignored on input to encoders
  * or filters.
  */
 AVRational time_base;

#if FF_API_FRAME_PICTURE_NUMBER
 /**
  * picture number in bitstream order
  */
 attribute_deprecated int coded_picture_number;
 /**
  * picture number in display order
  */
 attribute_deprecated int display_picture_number;
#endif

 /**
  * quality (between 1 (good) and FF_LAMBDA_MAX (bad))
  */
 int quality;

 /**
  * for some private data of the user
  */
 void* opaque;

 /**
  * When decoding, this signals how much the picture must be delayed.
  * extra_delay = repeat_pict / (2*fps)
  */
 int repeat_pict;

 /**
  * The content of the picture is interlaced.
  */
 int interlaced_frame;

 /**
  * If the content is interlaced, is top field displayed first.
  */
 int top_field_first;

 /**
  * Tell user application that palette has changed from previous frame.
  */
 int palette_has_changed;

#if FF_API_REORDERED_OPAQUE
 /**
  * reordered opaque 64 bits (generally an integer or a double precision float
  * PTS but can be anything).
  * The user sets AVCodecContext.reordered_opaque to represent the input at
  * that time,
  * the decoder reorders values as needed and sets AVFrame.reordered_opaque
  * to exactly one of the values provided by the user through
  * AVCodecContext.reordered_opaque
  *
  * @deprecated Use AV_CODEC_FLAG_COPY_OPAQUE instead
  */
 attribute_deprecated int64_t reordered_opaque;
#endif

 /**
  * Sample rate of the audio data.
  */
 int sample_rate;

#if FF_API_OLD_CHANNEL_LAYOUT
 /**
  * Channel layout of the audio data.
  * @deprecated use ch_layout instead
  */
 attribute_deprecated uint64_t channel_layout;
#endif

 /**
  * AVBuffer references backing the data for this frame. All the pointers in
  * data and extended_data must point inside one of the buffers in buf or
  * extended_buf. This array must be filled contiguously -- if buf[i] is
  * non-NULL then buf[j] must also be non-NULL for all j < i.
  *
  * There may be at most one AVBuffer per data plane, so for video this array
  * always contains all the references. For planar audio with more than
  * AV_NUM_DATA_POINTERS channels, there may be more buffers than can fit in
  * this array. Then the extra AVBufferRef pointers are stored in the
  * extended_buf array.
  */
 AVBufferRef* buf[AV_NUM_DATA_POINTERS];

 /**
  * For planar audio which requires more than AV_NUM_DATA_POINTERS
  * AVBufferRef pointers, this array will hold all the references which
  * cannot fit into AVFrame.buf.
  *
  * Note that this is different from AVFrame.extended_data, which always
  * contains all the pointers. This array only contains the extra pointers,
  * which cannot fit into AVFrame.buf.
  *
  * This array is always allocated using av_malloc() by whoever constructs
  * the frame. It is freed in av_frame_unref().
  */
 AVBufferRef** extended_buf;
 /**
  * Number of elements in extended_buf.
  */
 int nb_extended_buf;

 AVFrameSideData** side_data;
 int nb_side_data;

/**
* @defgroup lavu_frame_flags AV_FRAME_FLAGS
* @ingroup lavu_frame
* Flags describing additional frame properties.
*
* @{
*/

/**
* The frame data may be corrupted, e.g. due to decoding errors.
*/
#define AV_FRAME_FLAG_CORRUPT (1 << 0)
/**
* A flag to mark the frames which need to be decoded, but shouldn't be output.
*/
#define AV_FRAME_FLAG_DISCARD (1 << 2)
 /**
  * @}
  */

 /**
  * Frame flags, a combination of @ref lavu_frame_flags
  */
 int flags;

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

 enum AVColorPrimaries color_primaries;

 enum AVColorTransferCharacteristic color_trc;

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

 enum AVChromaLocation chroma_location;

 /**
  * frame timestamp estimated using various heuristics, in stream time base
  * - encoding: unused
  * - decoding: set by libavcodec, read by user.
  */
 int64_t best_effort_timestamp;

 /**
  * reordered pos from the last AVPacket that has been input into the decoder
  * - encoding: unused
  * - decoding: Read by user.
  */
 int64_t pkt_pos;

#if FF_API_PKT_DURATION
 /**
  * duration of the corresponding packet, expressed in
  * AVStream->time_base units, 0 if unknown.
  * - encoding: unused
  * - decoding: Read by user.
  *
  * @deprecated use duration instead
  */
 attribute_deprecated int64_t pkt_duration;
#endif

 /**
  * metadata.
  * - encoding: Set by user.
  * - decoding: Set by libavcodec.
  */
 AVDictionary* metadata;

 /**
  * decode error flags of the frame, set to a combination of
  * FF_DECODE_ERROR_xxx flags if the decoder produced a frame, but there
  * were errors during the decoding.
  * - encoding: unused
  * - decoding: set by libavcodec, read by user.
  */
 int decode_error_flags;
#define FF_DECODE_ERROR_INVALID_BITSTREAM 1
#define FF_DECODE_ERROR_MISSING_REFERENCE 2
#define FF_DECODE_ERROR_CONCEALMENT_ACTIVE 4
#define FF_DECODE_ERROR_DECODE_SLICES 8

#if FF_API_OLD_CHANNEL_LAYOUT
 /**
  * number of audio channels, only used for audio.
  * - encoding: unused
  * - decoding: Read by user.
  * @deprecated use ch_layout instead
  */
 attribute_deprecated int channels;
#endif

 /**
  * size of the corresponding packet containing the compressed
  * frame.
  * It is set to a negative value if unknown.
  * - encoding: unused
  * - decoding: set by libavcodec, read by user.
  */
 int pkt_size;

 /**
  * For hwaccel-format frames, this should be a reference to the
  * AVHWFramesContext describing the frame.
  */
 AVBufferRef* hw_frames_ctx;

 /**
  * AVBufferRef for free use by the API user. FFmpeg will never check the
  * contents of the buffer ref. FFmpeg calls av_buffer_unref() on it when
  * the frame is unreferenced. av_frame_copy_props() calls create a new
  * reference with av_buffer_ref() for the target frame's opaque_ref field.
  *
  * This is unrelated to the opaque field, although it serves a similar
  * purpose.
  */
 AVBufferRef* opaque_ref;

 /**
  * @anchor cropping
  * @name Cropping
  * Video frames only. The number of pixels to discard from the the
  * top/bottom/left/right border of the frame to obtain the sub-rectangle of
  * the frame intended for presentation.
  * @{
  */
 size_t crop_top;
 size_t crop_bottom;
 size_t crop_left;
 size_t crop_right;
 /**
  * @}
  */

 /**
  * AVBufferRef for internal use by a single libav* library.
  * Must not be used to transfer data between libraries.
  * Has to be NULL when ownership of the frame leaves the respective library.
  *
  * Code outside the FFmpeg libs should never check or change the contents of
  * the buffer ref.
  *
  * FFmpeg calls av_buffer_unref() on it when the frame is unreferenced.
  * av_frame_copy_props() calls create a new reference with av_buffer_ref()
  * for the target frame's private_ref field.
  */
 AVBufferRef* private_ref;

 /**
  * Channel layout of the audio data.
  */
 AVChannelLayout ch_layout;

 /**
  * Duration of the frame, in the same units as pts. 0 if unknown.
  */
 int64_t duration;
} AVFrame;

/**
* Allocate an AVFrame and set its fields to default values.  The resulting
* struct must be freed using av_frame_free().
*
* @return An AVFrame filled with default values or NULL on failure.
*
* @note this only allocates the AVFrame itself, not the data buffers. Those
* must be allocated through other means, e.g. with av_frame_get_buffer() or
* manually.
*/
AVFrame* av_frame_alloc(void);

/**
* Free the frame and any dynamically allocated objects in it,
* e.g. extended_data. If the frame is reference counted, it will be
* unreferenced first.
*
* @param frame frame to be freed. The pointer will be set to NULL.
*/
void av_frame_free(AVFrame** frame);

/**
* Set up a new reference to the data described by the source frame.
*
* Copy frame properties from src to dst and create a new reference for each
* AVBufferRef from src.
*
* If src is not reference counted, new buffers are allocated and the data is
* copied.
*
* @warning: dst MUST have been either unreferenced with av_frame_unref(dst),
*           or newly allocated with av_frame_alloc() before calling this
*           function, or undefined behavior will occur.
*
* @return 0 on success, a negative AVERROR on error
*/
int av_frame_ref(AVFrame* dst, const AVFrame* src);

/**
* Create a new frame that references the same data as src.
*
* This is a shortcut for av_frame_alloc()+av_frame_ref().
*
* @return newly created AVFrame on success, NULL on error.
*/
AVFrame* av_frame_clone(const AVFrame* src);

/**
* Unreference all the buffers referenced by frame and reset the frame fields.
*/
void av_frame_unref(AVFrame* frame);

/**
* Move everything contained in src to dst and reset src.
*
* @warning: dst is not unreferenced, but directly overwritten without reading
*           or deallocating its contents. Call av_frame_unref(dst) manually
*           before calling this function to ensure that no memory is leaked.
*/
void av_frame_move_ref(AVFrame* dst, AVFrame* src);

/**
* Allocate new buffer(s) for audio or video data.
*
* The following fields must be set on frame before calling this function:
* - format (pixel format for video, sample format for audio)
* - width and height for video
* - nb_samples and ch_layout for audio
*
* This function will fill AVFrame.data and AVFrame.buf arrays and, if
* necessary, allocate and fill AVFrame.extended_data and AVFrame.extended_buf.
* For planar formats, one buffer will be allocated for each plane.
*
* @warning: if frame already has been allocated, calling this function will
*           leak memory. In addition, undefined behavior can occur in certain
*           cases.
*
* @param frame frame in which to store the new buffers.
* @param align Required buffer size alignment. If equal to 0, alignment will be
*              chosen automatically for the current CPU. It is highly
*              recommended to pass 0 here unless you know what you are doing.
*
* @return 0 on success, a negative AVERROR on error.
*/
int av_frame_get_buffer(AVFrame* frame, int align);

/**
* Check if the frame data is writable.
*
* @return A positive value if the frame data is writable (which is true if and
* only if each of the underlying buffers has only one reference, namely the one
* stored in this frame). Return 0 otherwise.
*
* If 1 is returned the answer is valid until av_buffer_ref() is called on any
* of the underlying AVBufferRefs (e.g. through av_frame_ref() or directly).
*
* @see av_frame_make_writable(), av_buffer_is_writable()
*/
int av_frame_is_writable(AVFrame* frame);

/**
* Ensure that the frame data is writable, avoiding data copy if possible.
*
* Do nothing if the frame is writable, allocate new buffers and copy the data
* if it is not. Non-refcounted frames behave as non-writable, i.e. a copy
* is always made.
*
* @return 0 on success, a negative AVERROR on error.
*
* @see av_frame_is_writable(), av_buffer_is_writable(),
* av_buffer_make_writable()
*/
int av_frame_make_writable(AVFrame* frame);

/**
* Copy the frame data from src to dst.
*
* This function does not allocate anything, dst must be already initialized and
* allocated with the same parameters as src.
*
* This function only copies the frame data (i.e. the contents of the data /
* extended data arrays), not any other properties.
*
* @return >= 0 on success, a negative AVERROR on error.
*/
int av_frame_copy(AVFrame* dst, const AVFrame* src);

/**
* Copy only "metadata" fields from src to dst.
*
* Metadata for the purpose of this function are those fields that do not affect
* the data layout in the buffers.  E.g. pts, sample rate (for audio) or sample
* aspect ratio (for video), but not width/height or channel layout.
* Side data is also copied.
*/
int av_frame_copy_props(AVFrame* dst, const AVFrame* src);

/**
* Get the buffer reference a given data plane is stored in.
*
* @param frame the frame to get the plane's buffer from
* @param plane index of the data plane of interest in frame->extended_data.
*
* @return the buffer reference that contains the plane or NULL if the input
* frame is not valid.
*/
AVBufferRef* av_frame_get_plane_buffer(AVFrame* frame, int plane);

/**
* Add a new side data to a frame.
*
* @param frame a frame to which the side data should be added
* @param type type of the added side data
* @param size size of the side data
*
* @return newly added side data on success, NULL on error
*/
AVFrameSideData* av_frame_new_side_data(AVFrame* frame,
                                       enum AVFrameSideDataType type,
                                       size_t size);

/**
* Add a new side data to a frame from an existing AVBufferRef
*
* @param frame a frame to which the side data should be added
* @param type  the type of the added side data
* @param buf   an AVBufferRef to add as side data. The ownership of
*              the reference is transferred to the frame.
*
* @return newly added side data on success, NULL on error. On failure
*         the frame is unchanged and the AVBufferRef remains owned by
*         the caller.
*/
AVFrameSideData* av_frame_new_side_data_from_buf(AVFrame* frame,
                                                enum AVFrameSideDataType type,
                                                AVBufferRef* buf);

/**
* @return a pointer to the side data of a given type on success, NULL if there
* is no side data with such type in this frame.
*/
AVFrameSideData* av_frame_get_side_data(const AVFrame* frame,
                                       enum AVFrameSideDataType type);

/**
* Remove and free all side data instances of the given type.
*/
void av_frame_remove_side_data(AVFrame* frame, enum AVFrameSideDataType type);

/**
* Flags for frame cropping.
*/
enum {
 /**
  * Apply the maximum possible cropping, even if it requires setting the
  * AVFrame.data[] entries to unaligned pointers. Passing unaligned data
  * to FFmpeg API is generally not allowed, and causes undefined behavior
  * (such as crashes). You can pass unaligned data only to FFmpeg APIs that
  * are explicitly documented to accept it. Use this flag only if you
  * absolutely know what you are doing.
  */
 AV_FRAME_CROP_UNALIGNED = 1 << 0,
};

/**
* Crop the given video AVFrame according to its crop_left/crop_top/crop_right/
* crop_bottom fields. If cropping is successful, the function will adjust the
* data pointers and the width/height fields, and set the crop fields to 0.
*
* In all cases, the cropping boundaries will be rounded to the inherent
* alignment of the pixel format. In some cases, such as for opaque hwaccel
* formats, the left/top cropping is ignored. The crop fields are set to 0 even
* if the cropping was rounded or ignored.
*
* @param frame the frame which should be cropped
* @param flags Some combination of AV_FRAME_CROP_* flags, or 0.
*
* @return >= 0 on success, a negative AVERROR on error. If the cropping fields
* were invalid, AVERROR(ERANGE) is returned, and nothing is changed.
*/
int av_frame_apply_cropping(AVFrame* frame, int flags);

/**
* @return a string identifying the side data type
*/
const char* av_frame_side_data_name(enum AVFrameSideDataType type);

/**
* @}
*/

#endif /* AVUTIL_FRAME_H */