tor-browser

decode.c (74668B)

---

/*
* generic decoding-related code
*
* 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
*/

#include <stdint.h>
#include <stdbool.h>
#include <string.h>

#include "config.h"

#if CONFIG_ICONV
# include <iconv.h>
#endif

#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/common.h"
#include "libavutil/emms.h"
#include "libavutil/frame.h"
#include "libavutil/hwcontext.h"
#include "libavutil/imgutils.h"
#include "libavutil/internal.h"
#include "libavutil/mastering_display_metadata.h"
#include "libavutil/mem.h"
#include "libavutil/stereo3d.h"

#include "avcodec.h"
#include "avcodec_internal.h"
#include "bytestream.h"
#include "bsf.h"
#include "codec_desc.h"
#include "codec_internal.h"
#include "decode.h"
#include "hwaccel_internal.h"
#include "hwconfig.h"
#include "internal.h"
#include "lcevcdec.h"
#include "packet_internal.h"
#include "progressframe.h"
#include "libavutil/refstruct.h"
#include "thread.h"
#include "threadprogress.h"

typedef struct DecodeContext {
   AVCodecInternal avci;

   /**
    * This is set to AV_FRAME_FLAG_KEY for decoders of intra-only formats
    * (those whose codec descriptor has AV_CODEC_PROP_INTRA_ONLY set)
    * to set the flag generically.
    */
   int intra_only_flag;

   /**
    * This is set to AV_PICTURE_TYPE_I for intra only video decoders
    * and to AV_PICTURE_TYPE_NONE for other decoders. It is used to set
    * the AVFrame's pict_type before the decoder receives it.
    */
   enum AVPictureType initial_pict_type;

   /* to prevent infinite loop on errors when draining */
   int nb_draining_errors;

   /**
    * The caller has submitted a NULL packet on input.
    */
   int draining_started;

   int64_t pts_correction_num_faulty_pts; /// Number of incorrect PTS values so far
   int64_t pts_correction_num_faulty_dts; /// Number of incorrect DTS values so far
   int64_t pts_correction_last_pts;       /// PTS of the last frame
   int64_t pts_correction_last_dts;       /// DTS of the last frame

   /**
    * Bitmask indicating for which side data types we prefer user-supplied
    * (global or attached to packets) side data over bytestream.
    */
   uint64_t side_data_pref_mask;

   FFLCEVCContext *lcevc;
   int lcevc_frame;
   int width;
   int height;
} DecodeContext;

static DecodeContext *decode_ctx(AVCodecInternal *avci)
{
   return (DecodeContext *)avci;
}

static int apply_param_change(AVCodecContext *avctx, const AVPacket *avpkt)
{
   int ret;
   size_t size;
   const uint8_t *data;
   uint32_t flags;
   int64_t val;

   data = av_packet_get_side_data(avpkt, AV_PKT_DATA_PARAM_CHANGE, &size);
   if (!data)
       return 0;

   if (!(avctx->codec->capabilities & AV_CODEC_CAP_PARAM_CHANGE)) {
       av_log(avctx, AV_LOG_ERROR, "This decoder does not support parameter "
              "changes, but PARAM_CHANGE side data was sent to it.\n");
       ret = AVERROR(EINVAL);
       goto fail2;
   }

   if (size < 4)
       goto fail;

   flags = bytestream_get_le32(&data);
   size -= 4;

   if (flags & AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE) {
       if (size < 4)
           goto fail;
       val = bytestream_get_le32(&data);
       if (val <= 0 || val > INT_MAX) {
           av_log(avctx, AV_LOG_ERROR, "Invalid sample rate");
           ret = AVERROR_INVALIDDATA;
           goto fail2;
       }
       avctx->sample_rate = val;
       size -= 4;
   }
   if (flags & AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS) {
       if (size < 8)
           goto fail;
       avctx->width  = bytestream_get_le32(&data);
       avctx->height = bytestream_get_le32(&data);
       size -= 8;
       ret = ff_set_dimensions(avctx, avctx->width, avctx->height);
       if (ret < 0)
           goto fail2;
   }

   return 0;
fail:
   av_log(avctx, AV_LOG_ERROR, "PARAM_CHANGE side data too small.\n");
   ret = AVERROR_INVALIDDATA;
fail2:
   if (ret < 0) {
       av_log(avctx, AV_LOG_ERROR, "Error applying parameter changes.\n");
       if (avctx->err_recognition & AV_EF_EXPLODE)
           return ret;
   }
   return 0;
}

static int extract_packet_props(AVCodecInternal *avci, const AVPacket *pkt)
{
   int ret = 0;

   av_packet_unref(avci->last_pkt_props);
   if (pkt) {
       ret = av_packet_copy_props(avci->last_pkt_props, pkt);
#if FF_API_FRAME_PKT
       if (!ret)
           avci->last_pkt_props->stream_index = pkt->size; // Needed for ff_decode_frame_props().
#endif
   }
   return ret;
}

static int decode_bsfs_init(AVCodecContext *avctx)
{
   AVCodecInternal *avci = avctx->internal;
   const FFCodec *const codec = ffcodec(avctx->codec);
   int ret;

   if (avci->bsf)
       return 0;

   ret = av_bsf_list_parse_str(codec->bsfs, &avci->bsf);
   if (ret < 0) {
       av_log(avctx, AV_LOG_ERROR, "Error parsing decoder bitstream filters '%s': %s\n", codec->bsfs, av_err2str(ret));
       if (ret != AVERROR(ENOMEM))
           ret = AVERROR_BUG;
       goto fail;
   }

   /* We do not currently have an API for passing the input timebase into decoders,
    * but no filters used here should actually need it.
    * So we make up some plausible-looking number (the MPEG 90kHz timebase) */
   avci->bsf->time_base_in = (AVRational){ 1, 90000 };
   ret = avcodec_parameters_from_context(avci->bsf->par_in, avctx);
   if (ret < 0)
       goto fail;

   ret = av_bsf_init(avci->bsf);
   if (ret < 0)
       goto fail;

   return 0;
fail:
   av_bsf_free(&avci->bsf);
   return ret;
}

#if !HAVE_THREADS
#define ff_thread_get_packet(avctx, pkt) (AVERROR_BUG)
#define ff_thread_receive_frame(avctx, frame) (AVERROR_BUG)
#endif

static int decode_get_packet(AVCodecContext *avctx, AVPacket *pkt)
{
   AVCodecInternal *avci = avctx->internal;
   int ret;

   ret = av_bsf_receive_packet(avci->bsf, pkt);
   if (ret < 0)
       return ret;

   if (!(ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS)) {
       ret = extract_packet_props(avctx->internal, pkt);
       if (ret < 0)
           goto finish;
   }

   ret = apply_param_change(avctx, pkt);
   if (ret < 0)
       goto finish;

   return 0;
finish:
   av_packet_unref(pkt);
   return ret;
}

int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt)
{
   AVCodecInternal *avci = avctx->internal;
   DecodeContext     *dc = decode_ctx(avci);

   if (avci->draining)
       return AVERROR_EOF;

   /* If we are a worker thread, get the next packet from the threading
    * context. Otherwise we are the main (user-facing) context, so we get the
    * next packet from the input filterchain.
    */
   if (avctx->internal->is_frame_mt)
       return ff_thread_get_packet(avctx, pkt);

   while (1) {
       int ret = decode_get_packet(avctx, pkt);
       if (ret == AVERROR(EAGAIN) &&
           (!AVPACKET_IS_EMPTY(avci->buffer_pkt) || dc->draining_started)) {
           ret = av_bsf_send_packet(avci->bsf, avci->buffer_pkt);
           if (ret >= 0)
               continue;

           av_packet_unref(avci->buffer_pkt);
       }

       if (ret == AVERROR_EOF)
           avci->draining = 1;
       return ret;
   }
}

/**
* Attempt to guess proper monotonic timestamps for decoded video frames
* which might have incorrect times. Input timestamps may wrap around, in
* which case the output will as well.
*
* @param pts the pts field of the decoded AVPacket, as passed through
* AVFrame.pts
* @param dts the dts field of the decoded AVPacket
* @return one of the input values, may be AV_NOPTS_VALUE
*/
static int64_t guess_correct_pts(DecodeContext *dc,
                                int64_t reordered_pts, int64_t dts)
{
   int64_t pts = AV_NOPTS_VALUE;

   if (dts != AV_NOPTS_VALUE) {
       dc->pts_correction_num_faulty_dts += dts <= dc->pts_correction_last_dts;
       dc->pts_correction_last_dts = dts;
   } else if (reordered_pts != AV_NOPTS_VALUE)
       dc->pts_correction_last_dts = reordered_pts;

   if (reordered_pts != AV_NOPTS_VALUE) {
       dc->pts_correction_num_faulty_pts += reordered_pts <= dc->pts_correction_last_pts;
       dc->pts_correction_last_pts = reordered_pts;
   } else if(dts != AV_NOPTS_VALUE)
       dc->pts_correction_last_pts = dts;

   if ((dc->pts_correction_num_faulty_pts<=dc->pts_correction_num_faulty_dts || dts == AV_NOPTS_VALUE)
      && reordered_pts != AV_NOPTS_VALUE)
       pts = reordered_pts;
   else
       pts = dts;

   return pts;
}

static int discard_samples(AVCodecContext *avctx, AVFrame *frame, int64_t *discarded_samples)
{
   AVCodecInternal *avci = avctx->internal;
   AVFrameSideData *side;
   uint32_t discard_padding = 0;
   uint8_t skip_reason = 0;
   uint8_t discard_reason = 0;

   side = av_frame_get_side_data(frame, AV_FRAME_DATA_SKIP_SAMPLES);
   if (side && side->size >= 10) {
       avci->skip_samples = AV_RL32(side->data);
       avci->skip_samples = FFMAX(0, avci->skip_samples);
       discard_padding = AV_RL32(side->data + 4);
       av_log(avctx, AV_LOG_DEBUG, "skip %d / discard %d samples due to side data\n",
              avci->skip_samples, (int)discard_padding);
       skip_reason = AV_RL8(side->data + 8);
       discard_reason = AV_RL8(side->data + 9);
   }

   if ((avctx->flags2 & AV_CODEC_FLAG2_SKIP_MANUAL)) {
       if (!side && (avci->skip_samples || discard_padding))
           side = av_frame_new_side_data(frame, AV_FRAME_DATA_SKIP_SAMPLES, 10);
       if (side && (avci->skip_samples || discard_padding)) {
           AV_WL32(side->data, avci->skip_samples);
           AV_WL32(side->data + 4, discard_padding);
           AV_WL8(side->data + 8, skip_reason);
           AV_WL8(side->data + 9, discard_reason);
           avci->skip_samples = 0;
       }
       return 0;
   }
   av_frame_remove_side_data(frame, AV_FRAME_DATA_SKIP_SAMPLES);

   if ((frame->flags & AV_FRAME_FLAG_DISCARD)) {
       avci->skip_samples = FFMAX(0, avci->skip_samples - frame->nb_samples);
       *discarded_samples += frame->nb_samples;
       return AVERROR(EAGAIN);
   }

   if (avci->skip_samples > 0) {
       if (frame->nb_samples <= avci->skip_samples){
           *discarded_samples += frame->nb_samples;
           avci->skip_samples -= frame->nb_samples;
           av_log(avctx, AV_LOG_DEBUG, "skip whole frame, skip left: %d\n",
                  avci->skip_samples);
           return AVERROR(EAGAIN);
       } else {
           av_samples_copy(frame->extended_data, frame->extended_data, 0, avci->skip_samples,
                           frame->nb_samples - avci->skip_samples, avctx->ch_layout.nb_channels, frame->format);
           if (avctx->pkt_timebase.num && avctx->sample_rate) {
               int64_t diff_ts = av_rescale_q(avci->skip_samples,
                                              (AVRational){1, avctx->sample_rate},
                                              avctx->pkt_timebase);
               if (frame->pts != AV_NOPTS_VALUE)
                   frame->pts += diff_ts;
               if (frame->pkt_dts != AV_NOPTS_VALUE)
                   frame->pkt_dts += diff_ts;
               if (frame->duration >= diff_ts)
                   frame->duration -= diff_ts;
           } else
               av_log(avctx, AV_LOG_WARNING, "Could not update timestamps for skipped samples.\n");

           av_log(avctx, AV_LOG_DEBUG, "skip %d/%d samples\n",
                  avci->skip_samples, frame->nb_samples);
           *discarded_samples += avci->skip_samples;
           frame->nb_samples -= avci->skip_samples;
           avci->skip_samples = 0;
       }
   }

   if (discard_padding > 0 && discard_padding <= frame->nb_samples) {
       if (discard_padding == frame->nb_samples) {
           *discarded_samples += frame->nb_samples;
           return AVERROR(EAGAIN);
       } else {
           if (avctx->pkt_timebase.num && avctx->sample_rate) {
               int64_t diff_ts = av_rescale_q(frame->nb_samples - discard_padding,
                                              (AVRational){1, avctx->sample_rate},
                                              avctx->pkt_timebase);
               frame->duration = diff_ts;
           } else
               av_log(avctx, AV_LOG_WARNING, "Could not update timestamps for discarded samples.\n");

           av_log(avctx, AV_LOG_DEBUG, "discard %d/%d samples\n",
                  (int)discard_padding, frame->nb_samples);
           frame->nb_samples -= discard_padding;
       }
   }

   return 0;
}

/*
* The core of the receive_frame_wrapper for the decoders implementing
* the simple API. Certain decoders might consume partial packets without
* returning any output, so this function needs to be called in a loop until it
* returns EAGAIN.
**/
static inline int decode_simple_internal(AVCodecContext *avctx, AVFrame *frame, int64_t *discarded_samples)
{
   AVCodecInternal   *avci = avctx->internal;
   DecodeContext     *dc = decode_ctx(avci);
   AVPacket     *const pkt = avci->in_pkt;
   const FFCodec *const codec = ffcodec(avctx->codec);
   int got_frame, consumed;
   int ret;

   if (!pkt->data && !avci->draining) {
       av_packet_unref(pkt);
       ret = ff_decode_get_packet(avctx, pkt);
       if (ret < 0 && ret != AVERROR_EOF)
           return ret;
   }

   // Some codecs (at least wma lossless) will crash when feeding drain packets
   // after EOF was signaled.
   if (avci->draining_done)
       return AVERROR_EOF;

   if (!pkt->data &&
       !(avctx->codec->capabilities & AV_CODEC_CAP_DELAY))
       return AVERROR_EOF;

   got_frame = 0;

   frame->pict_type = dc->initial_pict_type;
   frame->flags    |= dc->intra_only_flag;
   consumed = codec->cb.decode(avctx, frame, &got_frame, pkt);

   if (!(codec->caps_internal & FF_CODEC_CAP_SETS_PKT_DTS))
       frame->pkt_dts = pkt->dts;
   if (avctx->codec->type == AVMEDIA_TYPE_VIDEO) {
#if FF_API_FRAME_PKT
FF_DISABLE_DEPRECATION_WARNINGS
       if(!avctx->has_b_frames)
           frame->pkt_pos = pkt->pos;
FF_ENABLE_DEPRECATION_WARNINGS
#endif
   }
   emms_c();

   if (avctx->codec->type == AVMEDIA_TYPE_VIDEO) {
       ret = (!got_frame || frame->flags & AV_FRAME_FLAG_DISCARD)
                         ? AVERROR(EAGAIN)
                         : 0;
   } else if (avctx->codec->type == AVMEDIA_TYPE_AUDIO) {
       ret =  !got_frame ? AVERROR(EAGAIN)
                         : discard_samples(avctx, frame, discarded_samples);
   } else
       av_assert0(0);

   if (ret == AVERROR(EAGAIN))
       av_frame_unref(frame);

   // FF_CODEC_CB_TYPE_DECODE decoders must not return AVERROR EAGAIN
   // code later will add AVERROR(EAGAIN) to a pointer
   av_assert0(consumed != AVERROR(EAGAIN));
   if (consumed < 0)
       ret = consumed;
   if (consumed >= 0 && avctx->codec->type == AVMEDIA_TYPE_VIDEO)
       consumed = pkt->size;

   if (!ret)
       av_assert0(frame->buf[0]);
   if (ret == AVERROR(EAGAIN))
       ret = 0;

   /* do not stop draining when got_frame != 0 or ret < 0 */
   if (avci->draining && !got_frame) {
       if (ret < 0) {
           /* prevent infinite loop if a decoder wrongly always return error on draining */
           /* reasonable nb_errors_max = maximum b frames + thread count */
           int nb_errors_max = 20 + (HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME ?
                               avctx->thread_count : 1);

           if (decode_ctx(avci)->nb_draining_errors++ >= nb_errors_max) {
               av_log(avctx, AV_LOG_ERROR, "Too many errors when draining, this is a bug. "
                      "Stop draining and force EOF.\n");
               avci->draining_done = 1;
               ret = AVERROR_BUG;
           }
       } else {
           avci->draining_done = 1;
       }
   }

   if (consumed >= pkt->size || ret < 0) {
       av_packet_unref(pkt);
   } else {
       pkt->data                += consumed;
       pkt->size                -= consumed;
       pkt->pts                  = AV_NOPTS_VALUE;
       pkt->dts                  = AV_NOPTS_VALUE;
       if (!(codec->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS)) {
#if FF_API_FRAME_PKT
           // See extract_packet_props() comment.
           avci->last_pkt_props->stream_index = avci->last_pkt_props->stream_index - consumed;
#endif
           avci->last_pkt_props->pts = AV_NOPTS_VALUE;
           avci->last_pkt_props->dts = AV_NOPTS_VALUE;
       }
   }

   return ret;
}

#if CONFIG_LCMS2
static int detect_colorspace(AVCodecContext *avctx, AVFrame *frame)
{
   AVCodecInternal *avci = avctx->internal;
   enum AVColorTransferCharacteristic trc;
   AVColorPrimariesDesc coeffs;
   enum AVColorPrimaries prim;
   cmsHPROFILE profile;
   AVFrameSideData *sd;
   int ret;
   if (!(avctx->flags2 & AV_CODEC_FLAG2_ICC_PROFILES))
       return 0;

   sd = av_frame_get_side_data(frame, AV_FRAME_DATA_ICC_PROFILE);
   if (!sd || !sd->size)
       return 0;

   if (!avci->icc.avctx) {
       ret = ff_icc_context_init(&avci->icc, avctx);
       if (ret < 0)
           return ret;
   }

   profile = cmsOpenProfileFromMemTHR(avci->icc.ctx, sd->data, sd->size);
   if (!profile)
       return AVERROR_INVALIDDATA;

   ret = ff_icc_profile_sanitize(&avci->icc, profile);
   if (!ret)
       ret = ff_icc_profile_read_primaries(&avci->icc, profile, &coeffs);
   if (!ret)
       ret = ff_icc_profile_detect_transfer(&avci->icc, profile, &trc);
   cmsCloseProfile(profile);
   if (ret < 0)
       return ret;

   prim = av_csp_primaries_id_from_desc(&coeffs);
   if (prim != AVCOL_PRI_UNSPECIFIED)
       frame->color_primaries = prim;
   if (trc != AVCOL_TRC_UNSPECIFIED)
       frame->color_trc = trc;
   return 0;
}
#else /* !CONFIG_LCMS2 */
static int detect_colorspace(av_unused AVCodecContext *c, av_unused AVFrame *f)
{
   return 0;
}
#endif

static int fill_frame_props(const AVCodecContext *avctx, AVFrame *frame)
{
   int ret;

   if (frame->color_primaries == AVCOL_PRI_UNSPECIFIED)
       frame->color_primaries = avctx->color_primaries;
   if (frame->color_trc == AVCOL_TRC_UNSPECIFIED)
       frame->color_trc = avctx->color_trc;
   if (frame->colorspace == AVCOL_SPC_UNSPECIFIED)
       frame->colorspace = avctx->colorspace;
   if (frame->color_range == AVCOL_RANGE_UNSPECIFIED)
       frame->color_range = avctx->color_range;
   if (frame->chroma_location == AVCHROMA_LOC_UNSPECIFIED)
       frame->chroma_location = avctx->chroma_sample_location;

   if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
           if (!frame->sample_aspect_ratio.num)  frame->sample_aspect_ratio = avctx->sample_aspect_ratio;
           if (frame->format == AV_PIX_FMT_NONE) frame->format              = avctx->pix_fmt;
   } else if (avctx->codec->type == AVMEDIA_TYPE_AUDIO) {
       if (frame->format == AV_SAMPLE_FMT_NONE)
           frame->format = avctx->sample_fmt;
       if (!frame->ch_layout.nb_channels) {
           ret = av_channel_layout_copy(&frame->ch_layout, &avctx->ch_layout);
           if (ret < 0)
               return ret;
       }
       if (!frame->sample_rate)
           frame->sample_rate = avctx->sample_rate;
   }

   return 0;
}

static int decode_simple_receive_frame(AVCodecContext *avctx, AVFrame *frame)
{
   int ret;
   int64_t discarded_samples = 0;

   while (!frame->buf[0]) {
       if (discarded_samples > avctx->max_samples)
           return AVERROR(EAGAIN);
       ret = decode_simple_internal(avctx, frame, &discarded_samples);
       if (ret < 0)
           return ret;
   }

   return 0;
}

int ff_decode_receive_frame_internal(AVCodecContext *avctx, AVFrame *frame)
{
   AVCodecInternal *avci = avctx->internal;
   DecodeContext     *dc = decode_ctx(avci);
   const FFCodec *const codec = ffcodec(avctx->codec);
   int ret;

   av_assert0(!frame->buf[0]);

   if (codec->cb_type == FF_CODEC_CB_TYPE_RECEIVE_FRAME) {
       while (1) {
           frame->pict_type = dc->initial_pict_type;
           frame->flags    |= dc->intra_only_flag;
           ret = codec->cb.receive_frame(avctx, frame);
           emms_c();
           if (!ret) {
               if (avctx->codec->type == AVMEDIA_TYPE_AUDIO) {
                   int64_t discarded_samples = 0;
                   ret = discard_samples(avctx, frame, &discarded_samples);
               }
               if (ret == AVERROR(EAGAIN) || (frame->flags & AV_FRAME_FLAG_DISCARD)) {
                   av_frame_unref(frame);
                   continue;
               }
           }
           break;
       }
   } else
       ret = decode_simple_receive_frame(avctx, frame);

   if (ret == AVERROR_EOF)
       avci->draining_done = 1;

   return ret;
}

static int decode_receive_frame_internal(AVCodecContext *avctx, AVFrame *frame)
{
   AVCodecInternal *avci = avctx->internal;
   DecodeContext     *dc = decode_ctx(avci);
   int ret, ok;

   if (avctx->active_thread_type & FF_THREAD_FRAME)
       ret = ff_thread_receive_frame(avctx, frame);
   else
       ret = ff_decode_receive_frame_internal(avctx, frame);

   /* preserve ret */
   ok = detect_colorspace(avctx, frame);
   if (ok < 0) {
       av_frame_unref(frame);
       return ok;
   }

   if (!ret) {
       if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
           if (!frame->width)
               frame->width = avctx->width;
           if (!frame->height)
               frame->height = avctx->height;
       }

       ret = fill_frame_props(avctx, frame);
       if (ret < 0) {
           av_frame_unref(frame);
           return ret;
       }

#if FF_API_FRAME_KEY
FF_DISABLE_DEPRECATION_WARNINGS
       frame->key_frame = !!(frame->flags & AV_FRAME_FLAG_KEY);
FF_ENABLE_DEPRECATION_WARNINGS
#endif
#if FF_API_INTERLACED_FRAME
FF_DISABLE_DEPRECATION_WARNINGS
       frame->interlaced_frame = !!(frame->flags & AV_FRAME_FLAG_INTERLACED);
       frame->top_field_first =  !!(frame->flags & AV_FRAME_FLAG_TOP_FIELD_FIRST);
FF_ENABLE_DEPRECATION_WARNINGS
#endif
       frame->best_effort_timestamp = guess_correct_pts(dc,
                                                        frame->pts,
                                                        frame->pkt_dts);

       /* the only case where decode data is not set should be decoders
        * that do not call ff_get_buffer() */
       av_assert0((frame->private_ref && frame->private_ref->size == sizeof(FrameDecodeData)) ||
                  !(avctx->codec->capabilities & AV_CODEC_CAP_DR1));

       if (frame->private_ref) {
           FrameDecodeData *fdd = (FrameDecodeData*)frame->private_ref->data;

           if (fdd->post_process) {
               ret = fdd->post_process(avctx, frame);
               if (ret < 0) {
                   av_frame_unref(frame);
                   return ret;
               }
           }
       }
   }

   /* free the per-frame decode data */
   av_buffer_unref(&frame->private_ref);

   return ret;
}

int attribute_align_arg avcodec_send_packet(AVCodecContext *avctx, const AVPacket *avpkt)
{
   AVCodecInternal *avci = avctx->internal;
   DecodeContext     *dc = decode_ctx(avci);
   int ret;

   if (!avcodec_is_open(avctx) || !av_codec_is_decoder(avctx->codec))
       return AVERROR(EINVAL);

   if (dc->draining_started)
       return AVERROR_EOF;

   if (avpkt && !avpkt->size && avpkt->data)
       return AVERROR(EINVAL);

   if (avpkt && (avpkt->data || avpkt->side_data_elems)) {
       if (!AVPACKET_IS_EMPTY(avci->buffer_pkt))
           return AVERROR(EAGAIN);
       ret = av_packet_ref(avci->buffer_pkt, avpkt);
       if (ret < 0)
           return ret;
   } else
       dc->draining_started = 1;

   if (!avci->buffer_frame->buf[0] && !dc->draining_started) {
       ret = decode_receive_frame_internal(avctx, avci->buffer_frame);
       if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF)
           return ret;
   }

   return 0;
}

static int apply_cropping(AVCodecContext *avctx, AVFrame *frame)
{
   /* make sure we are noisy about decoders returning invalid cropping data */
   if (frame->crop_left >= INT_MAX - frame->crop_right        ||
       frame->crop_top  >= INT_MAX - frame->crop_bottom       ||
       (frame->crop_left + frame->crop_right) >= frame->width ||
       (frame->crop_top + frame->crop_bottom) >= frame->height) {
       av_log(avctx, AV_LOG_WARNING,
              "Invalid cropping information set by a decoder: "
              "%"SIZE_SPECIFIER"/%"SIZE_SPECIFIER"/%"SIZE_SPECIFIER"/%"SIZE_SPECIFIER" "
              "(frame size %dx%d). This is a bug, please report it\n",
              frame->crop_left, frame->crop_right, frame->crop_top, frame->crop_bottom,
              frame->width, frame->height);
       frame->crop_left   = 0;
       frame->crop_right  = 0;
       frame->crop_top    = 0;
       frame->crop_bottom = 0;
       return 0;
   }

   if (!avctx->apply_cropping)
       return 0;

   return av_frame_apply_cropping(frame, avctx->flags & AV_CODEC_FLAG_UNALIGNED ?
                                         AV_FRAME_CROP_UNALIGNED : 0);
}

// make sure frames returned to the caller are valid
static int frame_validate(AVCodecContext *avctx, AVFrame *frame)
{
   if (!frame->buf[0] || frame->format < 0)
       goto fail;

   switch (avctx->codec_type) {
   case AVMEDIA_TYPE_VIDEO:
       if (frame->width <= 0 || frame->height <= 0)
           goto fail;
       break;
   case AVMEDIA_TYPE_AUDIO:
       if (!av_channel_layout_check(&frame->ch_layout) ||
           frame->sample_rate <= 0)
           goto fail;

       break;
   default: av_assert0(0);
   }

   return 0;
fail:
   av_log(avctx, AV_LOG_ERROR, "An invalid frame was output by a decoder. "
          "This is a bug, please report it.\n");
   return AVERROR_BUG;
}

int ff_decode_receive_frame(AVCodecContext *avctx, AVFrame *frame)
{
   AVCodecInternal *avci = avctx->internal;
   int ret;

   if (!avcodec_is_open(avctx) || !av_codec_is_decoder(avctx->codec))
       return AVERROR(EINVAL);

   if (avci->buffer_frame->buf[0]) {
       av_frame_move_ref(frame, avci->buffer_frame);
   } else {
       ret = decode_receive_frame_internal(avctx, frame);
       if (ret < 0)
           return ret;
   }

   ret = frame_validate(avctx, frame);
   if (ret < 0)
       goto fail;

   if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
       ret = apply_cropping(avctx, frame);
       if (ret < 0)
           goto fail;
   }

   avctx->frame_num++;

#if FF_API_DROPCHANGED
   if (avctx->flags & AV_CODEC_FLAG_DROPCHANGED) {

       if (avctx->frame_num == 1) {
           avci->initial_format = frame->format;
           switch(avctx->codec_type) {
           case AVMEDIA_TYPE_VIDEO:
               avci->initial_width  = frame->width;
               avci->initial_height = frame->height;
               break;
           case AVMEDIA_TYPE_AUDIO:
               avci->initial_sample_rate = frame->sample_rate ? frame->sample_rate :
                                                                avctx->sample_rate;
               ret = av_channel_layout_copy(&avci->initial_ch_layout, &frame->ch_layout);
               if (ret < 0)
                   goto fail;
               break;
           }
       }

       if (avctx->frame_num > 1) {
           int changed = avci->initial_format != frame->format;

           switch(avctx->codec_type) {
           case AVMEDIA_TYPE_VIDEO:
               changed |= avci->initial_width  != frame->width ||
                          avci->initial_height != frame->height;
               break;
           case AVMEDIA_TYPE_AUDIO:
               changed |= avci->initial_sample_rate    != frame->sample_rate ||
                          avci->initial_sample_rate    != avctx->sample_rate ||
                          av_channel_layout_compare(&avci->initial_ch_layout, &frame->ch_layout);
               break;
           }

           if (changed) {
               avci->changed_frames_dropped++;
               av_log(avctx, AV_LOG_INFO, "dropped changed frame #%"PRId64" pts %"PRId64
                                           " drop count: %d \n",
                                           avctx->frame_num, frame->pts,
                                           avci->changed_frames_dropped);
               ret = AVERROR_INPUT_CHANGED;
               goto fail;
           }
       }
   }
#endif
   return 0;
fail:
   av_frame_unref(frame);
   return ret;
}

static void get_subtitle_defaults(AVSubtitle *sub)
{
   memset(sub, 0, sizeof(*sub));
   sub->pts = AV_NOPTS_VALUE;
}

#define UTF8_MAX_BYTES 4 /* 5 and 6 bytes sequences should not be used */
static int recode_subtitle(AVCodecContext *avctx, const AVPacket **outpkt,
                          const AVPacket *inpkt, AVPacket *buf_pkt)
{
#if CONFIG_ICONV
   iconv_t cd = (iconv_t)-1;
   int ret = 0;
   char *inb, *outb;
   size_t inl, outl;
#endif

   if (avctx->sub_charenc_mode != FF_SUB_CHARENC_MODE_PRE_DECODER || inpkt->size == 0) {
       *outpkt = inpkt;
       return 0;
   }

#if CONFIG_ICONV
   inb = inpkt->data;
   inl = inpkt->size;

   if (inl >= INT_MAX / UTF8_MAX_BYTES - AV_INPUT_BUFFER_PADDING_SIZE) {
       av_log(avctx, AV_LOG_ERROR, "Subtitles packet is too big for recoding\n");
       return AVERROR(ERANGE);
   }

   cd = iconv_open("UTF-8", avctx->sub_charenc);
   av_assert0(cd != (iconv_t)-1);

   ret = av_new_packet(buf_pkt, inl * UTF8_MAX_BYTES);
   if (ret < 0)
       goto end;
   ret = av_packet_copy_props(buf_pkt, inpkt);
   if (ret < 0)
       goto end;
   outb = buf_pkt->data;
   outl = buf_pkt->size;

   if (iconv(cd, &inb, &inl, &outb, &outl) == (size_t)-1 ||
       iconv(cd, NULL, NULL, &outb, &outl) == (size_t)-1 ||
       outl >= buf_pkt->size || inl != 0) {
       ret = FFMIN(AVERROR(errno), -1);
       av_log(avctx, AV_LOG_ERROR, "Unable to recode subtitle event \"%s\" "
              "from %s to UTF-8\n", inpkt->data, avctx->sub_charenc);
       goto end;
   }
   buf_pkt->size -= outl;
   memset(buf_pkt->data + buf_pkt->size, 0, outl);
   *outpkt = buf_pkt;

   ret = 0;
end:
   if (ret < 0)
       av_packet_unref(buf_pkt);
   if (cd != (iconv_t)-1)
       iconv_close(cd);
   return ret;
#else
   av_log(avctx, AV_LOG_ERROR, "requesting subtitles recoding without iconv");
   return AVERROR(EINVAL);
#endif
}

static int utf8_check(const uint8_t *str)
{
   const uint8_t *byte;
   uint32_t codepoint, min;

   while (*str) {
       byte = str;
       GET_UTF8(codepoint, *(byte++), return 0;);
       min = byte - str == 1 ? 0 : byte - str == 2 ? 0x80 :
             1 << (5 * (byte - str) - 4);
       if (codepoint < min || codepoint >= 0x110000 ||
           codepoint == 0xFFFE /* BOM */ ||
           codepoint >= 0xD800 && codepoint <= 0xDFFF /* surrogates */)
           return 0;
       str = byte;
   }
   return 1;
}

int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
                            int *got_sub_ptr, const AVPacket *avpkt)
{
   int ret = 0;

   if (!avpkt->data && avpkt->size) {
       av_log(avctx, AV_LOG_ERROR, "invalid packet: NULL data, size != 0\n");
       return AVERROR(EINVAL);
   }
   if (!avctx->codec)
       return AVERROR(EINVAL);
   if (ffcodec(avctx->codec)->cb_type != FF_CODEC_CB_TYPE_DECODE_SUB) {
       av_log(avctx, AV_LOG_ERROR, "Codec not subtitle decoder\n");
       return AVERROR(EINVAL);
   }

   *got_sub_ptr = 0;
   get_subtitle_defaults(sub);

   if ((avctx->codec->capabilities & AV_CODEC_CAP_DELAY) || avpkt->size) {
       AVCodecInternal *avci = avctx->internal;
       const AVPacket *pkt;

       ret = recode_subtitle(avctx, &pkt, avpkt, avci->buffer_pkt);
       if (ret < 0)
           return ret;

       if (avctx->pkt_timebase.num && avpkt->pts != AV_NOPTS_VALUE)
           sub->pts = av_rescale_q(avpkt->pts,
                                   avctx->pkt_timebase, AV_TIME_BASE_Q);
       ret = ffcodec(avctx->codec)->cb.decode_sub(avctx, sub, got_sub_ptr, pkt);
       if (pkt == avci->buffer_pkt) // did we recode?
           av_packet_unref(avci->buffer_pkt);
       if (ret < 0) {
           *got_sub_ptr = 0;
           avsubtitle_free(sub);
           return ret;
       }
       av_assert1(!sub->num_rects || *got_sub_ptr);

       if (sub->num_rects && !sub->end_display_time && avpkt->duration &&
           avctx->pkt_timebase.num) {
           AVRational ms = { 1, 1000 };
           sub->end_display_time = av_rescale_q(avpkt->duration,
                                                avctx->pkt_timebase, ms);
       }

       if (avctx->codec_descriptor->props & AV_CODEC_PROP_BITMAP_SUB)
           sub->format = 0;
       else if (avctx->codec_descriptor->props & AV_CODEC_PROP_TEXT_SUB)
           sub->format = 1;

       for (unsigned i = 0; i < sub->num_rects; i++) {
           if (avctx->sub_charenc_mode != FF_SUB_CHARENC_MODE_IGNORE &&
               sub->rects[i]->ass && !utf8_check(sub->rects[i]->ass)) {
               av_log(avctx, AV_LOG_ERROR,
                      "Invalid UTF-8 in decoded subtitles text; "
                      "maybe missing -sub_charenc option\n");
               avsubtitle_free(sub);
               *got_sub_ptr = 0;
               return AVERROR_INVALIDDATA;
           }
       }

       if (*got_sub_ptr)
           avctx->frame_num++;
   }

   return ret;
}

enum AVPixelFormat avcodec_default_get_format(struct AVCodecContext *avctx,
                                             const enum AVPixelFormat *fmt)
{
   const AVPixFmtDescriptor *desc;
   const AVCodecHWConfig *config;
   int i, n;

   // If a device was supplied when the codec was opened, assume that the
   // user wants to use it.
   if (avctx->hw_device_ctx && ffcodec(avctx->codec)->hw_configs) {
       AVHWDeviceContext *device_ctx =
           (AVHWDeviceContext*)avctx->hw_device_ctx->data;
       for (i = 0;; i++) {
           config = &ffcodec(avctx->codec)->hw_configs[i]->public;
           if (!config)
               break;
           if (!(config->methods &
                 AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX))
               continue;
           if (device_ctx->type != config->device_type)
               continue;
           for (n = 0; fmt[n] != AV_PIX_FMT_NONE; n++) {
               if (config->pix_fmt == fmt[n])
                   return fmt[n];
           }
       }
   }
   // No device or other setup, so we have to choose from things which
   // don't any other external information.

   // If the last element of the list is a software format, choose it
   // (this should be best software format if any exist).
   for (n = 0; fmt[n] != AV_PIX_FMT_NONE; n++);
   desc = av_pix_fmt_desc_get(fmt[n - 1]);
   if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
       return fmt[n - 1];

   // Finally, traverse the list in order and choose the first entry
   // with no external dependencies (if there is no hardware configuration
   // information available then this just picks the first entry).
   for (n = 0; fmt[n] != AV_PIX_FMT_NONE; n++) {
       for (i = 0;; i++) {
           config = avcodec_get_hw_config(avctx->codec, i);
           if (!config)
               break;
           if (config->pix_fmt == fmt[n])
               break;
       }
       if (!config) {
           // No specific config available, so the decoder must be able
           // to handle this format without any additional setup.
           return fmt[n];
       }
       if (config->methods & AV_CODEC_HW_CONFIG_METHOD_INTERNAL) {
           // Usable with only internal setup.
           return fmt[n];
       }
   }

   // Nothing is usable, give up.
   return AV_PIX_FMT_NONE;
}

int ff_decode_get_hw_frames_ctx(AVCodecContext *avctx,
                               enum AVHWDeviceType dev_type)
{
   AVHWDeviceContext *device_ctx;
   AVHWFramesContext *frames_ctx;
   int ret;

   if (!avctx->hwaccel)
       return AVERROR(ENOSYS);

   if (avctx->hw_frames_ctx)
       return 0;
   if (!avctx->hw_device_ctx) {
       av_log(avctx, AV_LOG_ERROR, "A hardware frames or device context is "
               "required for hardware accelerated decoding.\n");
       return AVERROR(EINVAL);
   }

   device_ctx = (AVHWDeviceContext *)avctx->hw_device_ctx->data;
   if (device_ctx->type != dev_type) {
       av_log(avctx, AV_LOG_ERROR, "Device type %s expected for hardware "
              "decoding, but got %s.\n", av_hwdevice_get_type_name(dev_type),
              av_hwdevice_get_type_name(device_ctx->type));
       return AVERROR(EINVAL);
   }

   ret = avcodec_get_hw_frames_parameters(avctx,
                                          avctx->hw_device_ctx,
                                          avctx->hwaccel->pix_fmt,
                                          &avctx->hw_frames_ctx);
   if (ret < 0)
       return ret;

   frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;


   if (frames_ctx->initial_pool_size) {
       // We guarantee 4 base work surfaces. The function above guarantees 1
       // (the absolute minimum), so add the missing count.
       frames_ctx->initial_pool_size += 3;
   }

   ret = av_hwframe_ctx_init(avctx->hw_frames_ctx);
   if (ret < 0) {
       av_buffer_unref(&avctx->hw_frames_ctx);
       return ret;
   }

   return 0;
}

int avcodec_get_hw_frames_parameters(AVCodecContext *avctx,
                                    AVBufferRef *device_ref,
                                    enum AVPixelFormat hw_pix_fmt,
                                    AVBufferRef **out_frames_ref)
{
   AVBufferRef *frames_ref = NULL;
   const AVCodecHWConfigInternal *hw_config;
   const FFHWAccel *hwa;
   int i, ret;
   bool clean_priv_data = false;

   for (i = 0;; i++) {
       hw_config = ffcodec(avctx->codec)->hw_configs[i];
       if (!hw_config)
           return AVERROR(ENOENT);
       if (hw_config->public.pix_fmt == hw_pix_fmt)
           break;
   }

   hwa = hw_config->hwaccel;
   if (!hwa || !hwa->frame_params)
       return AVERROR(ENOENT);

   frames_ref = av_hwframe_ctx_alloc(device_ref);
   if (!frames_ref)
       return AVERROR(ENOMEM);

   if (!avctx->internal->hwaccel_priv_data) {
       avctx->internal->hwaccel_priv_data =
           av_mallocz(hwa->priv_data_size);
       if (!avctx->internal->hwaccel_priv_data) {
           av_buffer_unref(&frames_ref);
           return AVERROR(ENOMEM);
       }
       clean_priv_data = true;
   }

   ret = hwa->frame_params(avctx, frames_ref);
   if (ret >= 0) {
       AVHWFramesContext *frames_ctx = (AVHWFramesContext*)frames_ref->data;

       if (frames_ctx->initial_pool_size) {
           // If the user has requested that extra output surfaces be
           // available then add them here.
           if (avctx->extra_hw_frames > 0)
               frames_ctx->initial_pool_size += avctx->extra_hw_frames;

           // If frame threading is enabled then an extra surface per thread
           // is also required.
           if (avctx->active_thread_type & FF_THREAD_FRAME)
               frames_ctx->initial_pool_size += avctx->thread_count;
       }

       *out_frames_ref = frames_ref;
   } else {
       if (clean_priv_data)
           av_freep(&avctx->internal->hwaccel_priv_data);
       av_buffer_unref(&frames_ref);
   }
   return ret;
}

static int hwaccel_init(AVCodecContext *avctx,
                       const FFHWAccel *hwaccel)
{
   int err;

   if (hwaccel->p.capabilities & AV_HWACCEL_CODEC_CAP_EXPERIMENTAL &&
       avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL) {
       av_log(avctx, AV_LOG_WARNING, "Ignoring experimental hwaccel: %s\n",
              hwaccel->p.name);
       return AVERROR_PATCHWELCOME;
   }

   if (!avctx->internal->hwaccel_priv_data && hwaccel->priv_data_size) {
       avctx->internal->hwaccel_priv_data =
           av_mallocz(hwaccel->priv_data_size);
       if (!avctx->internal->hwaccel_priv_data)
           return AVERROR(ENOMEM);
   }

   avctx->hwaccel = &hwaccel->p;
   if (hwaccel->init) {
       err = hwaccel->init(avctx);
       if (err < 0) {
           av_log(avctx, AV_LOG_ERROR, "Failed setup for format %s: "
                  "hwaccel initialisation returned error.\n",
                  av_get_pix_fmt_name(hwaccel->p.pix_fmt));
           av_freep(&avctx->internal->hwaccel_priv_data);
           avctx->hwaccel = NULL;
           return err;
       }
   }

   return 0;
}

void ff_hwaccel_uninit(AVCodecContext *avctx)
{
   if (FF_HW_HAS_CB(avctx, uninit))
       FF_HW_SIMPLE_CALL(avctx, uninit);

   av_freep(&avctx->internal->hwaccel_priv_data);

   avctx->hwaccel = NULL;

   av_buffer_unref(&avctx->hw_frames_ctx);
}

int ff_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt)
{
   const AVPixFmtDescriptor *desc;
   enum AVPixelFormat *choices;
   enum AVPixelFormat ret, user_choice;
   const AVCodecHWConfigInternal *hw_config;
   const AVCodecHWConfig *config;
   int i, n, err;

   // Find end of list.
   for (n = 0; fmt[n] != AV_PIX_FMT_NONE; n++);
   // Must contain at least one entry.
   av_assert0(n >= 1);
   // If a software format is available, it must be the last entry.
   desc = av_pix_fmt_desc_get(fmt[n - 1]);
   if (desc->flags & AV_PIX_FMT_FLAG_HWACCEL) {
       // No software format is available.
   } else {
       avctx->sw_pix_fmt = fmt[n - 1];
   }

   choices = av_memdup(fmt, (n + 1) * sizeof(*choices));
   if (!choices)
       return AV_PIX_FMT_NONE;

   for (;;) {
       // Remove the previous hwaccel, if there was one.
       ff_hwaccel_uninit(avctx);

       user_choice = avctx->get_format(avctx, choices);
       if (user_choice == AV_PIX_FMT_NONE) {
           // Explicitly chose nothing, give up.
           ret = AV_PIX_FMT_NONE;
           break;
       }

       desc = av_pix_fmt_desc_get(user_choice);
       if (!desc) {
           av_log(avctx, AV_LOG_ERROR, "Invalid format returned by "
                  "get_format() callback.\n");
           ret = AV_PIX_FMT_NONE;
           break;
       }
       av_log(avctx, AV_LOG_DEBUG, "Format %s chosen by get_format().\n",
              desc->name);

       for (i = 0; i < n; i++) {
           if (choices[i] == user_choice)
               break;
       }
       if (i == n) {
           av_log(avctx, AV_LOG_ERROR, "Invalid return from get_format(): "
                  "%s not in possible list.\n", desc->name);
           ret = AV_PIX_FMT_NONE;
           break;
       }

       if (ffcodec(avctx->codec)->hw_configs) {
           for (i = 0;; i++) {
               hw_config = ffcodec(avctx->codec)->hw_configs[i];
               if (!hw_config)
                   break;
               if (hw_config->public.pix_fmt == user_choice)
                   break;
           }
       } else {
           hw_config = NULL;
       }

       if (!hw_config) {
           // No config available, so no extra setup required.
           ret = user_choice;
           break;
       }
       config = &hw_config->public;

       if (config->methods &
           AV_CODEC_HW_CONFIG_METHOD_HW_FRAMES_CTX &&
           avctx->hw_frames_ctx) {
           const AVHWFramesContext *frames_ctx =
               (AVHWFramesContext*)avctx->hw_frames_ctx->data;
           if (frames_ctx->format != user_choice) {
               av_log(avctx, AV_LOG_ERROR, "Invalid setup for format %s: "
                      "does not match the format of the provided frames "
                      "context.\n", desc->name);
               goto try_again;
           }
       } else if (config->methods &
                  AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX &&
                  avctx->hw_device_ctx) {
           const AVHWDeviceContext *device_ctx =
               (AVHWDeviceContext*)avctx->hw_device_ctx->data;
           if (device_ctx->type != config->device_type) {
               av_log(avctx, AV_LOG_ERROR, "Invalid setup for format %s: "
                      "does not match the type of the provided device "
                      "context.\n", desc->name);
               goto try_again;
           }
       } else if (config->methods &
                  AV_CODEC_HW_CONFIG_METHOD_INTERNAL) {
           // Internal-only setup, no additional configuration.
       } else if (config->methods &
                  AV_CODEC_HW_CONFIG_METHOD_AD_HOC) {
           // Some ad-hoc configuration we can't see and can't check.
       } else {
           av_log(avctx, AV_LOG_ERROR, "Invalid setup for format %s: "
                  "missing configuration.\n", desc->name);
           goto try_again;
       }
       if (hw_config->hwaccel) {
           av_log(avctx, AV_LOG_DEBUG, "Format %s requires hwaccel %s "
                  "initialisation.\n", desc->name, hw_config->hwaccel->p.name);
           err = hwaccel_init(avctx, hw_config->hwaccel);
           if (err < 0)
               goto try_again;
       }
       ret = user_choice;
       break;

   try_again:
       av_log(avctx, AV_LOG_DEBUG, "Format %s not usable, retrying "
              "get_format() without it.\n", desc->name);
       for (i = 0; i < n; i++) {
           if (choices[i] == user_choice)
               break;
       }
       for (; i + 1 < n; i++)
           choices[i] = choices[i + 1];
       --n;
   }

   if (ret < 0)
       ff_hwaccel_uninit(avctx);

   av_freep(&choices);
   return ret;
}

static const AVPacketSideData*
packet_side_data_get(const AVPacketSideData *sd, int nb_sd,
                    enum AVPacketSideDataType type)
{
   for (int i = 0; i < nb_sd; i++)
       if (sd[i].type == type)
           return &sd[i];

   return NULL;
}

const AVPacketSideData *ff_get_coded_side_data(const AVCodecContext *avctx,
                                              enum AVPacketSideDataType type)
{
   return packet_side_data_get(avctx->coded_side_data, avctx->nb_coded_side_data, type);
}

static int side_data_stereo3d_merge(AVFrameSideData *sd_frame,
                                   const AVPacketSideData *sd_pkt)
{
   const AVStereo3D *src;
   AVStereo3D       *dst;
   int ret;

   ret = av_buffer_make_writable(&sd_frame->buf);
   if (ret < 0)
       return ret;
   sd_frame->data = sd_frame->buf->data;

   dst = (      AVStereo3D*)sd_frame->data;
   src = (const AVStereo3D*)sd_pkt->data;

   if (dst->type == AV_STEREO3D_UNSPEC)
       dst->type = src->type;

   if (dst->view == AV_STEREO3D_VIEW_UNSPEC)
       dst->view = src->view;

   if (dst->primary_eye == AV_PRIMARY_EYE_NONE)
       dst->primary_eye = src->primary_eye;

   if (!dst->baseline)
       dst->baseline = src->baseline;

   if (!dst->horizontal_disparity_adjustment.num)
       dst->horizontal_disparity_adjustment = src->horizontal_disparity_adjustment;

   if (!dst->horizontal_field_of_view.num)
       dst->horizontal_field_of_view = src->horizontal_field_of_view;

   return 0;
}

static int side_data_map(AVFrame *dst,
                        const AVPacketSideData *sd_src, int nb_sd_src,
                        const SideDataMap *map)

{
   for (int i = 0; map[i].packet < AV_PKT_DATA_NB; i++) {
       const enum AVPacketSideDataType type_pkt   = map[i].packet;
       const enum AVFrameSideDataType  type_frame = map[i].frame;
       const AVPacketSideData *sd_pkt;
       AVFrameSideData *sd_frame;

       sd_pkt = packet_side_data_get(sd_src, nb_sd_src, type_pkt);
       if (!sd_pkt)
           continue;

       sd_frame = av_frame_get_side_data(dst, type_frame);
       if (sd_frame) {
           if (type_frame == AV_FRAME_DATA_STEREO3D) {
               int ret = side_data_stereo3d_merge(sd_frame, sd_pkt);
               if (ret < 0)
                   return ret;
           }

           continue;
       }

       sd_frame = av_frame_new_side_data(dst, type_frame, sd_pkt->size);
       if (!sd_frame)
           return AVERROR(ENOMEM);

       memcpy(sd_frame->data, sd_pkt->data, sd_pkt->size);
   }

   return 0;
}

static int add_metadata_from_side_data(const AVPacket *avpkt, AVFrame *frame)
{
   size_t size;
   const uint8_t *side_metadata;

   AVDictionary **frame_md = &frame->metadata;

   side_metadata = av_packet_get_side_data(avpkt,
                                           AV_PKT_DATA_STRINGS_METADATA, &size);
   return av_packet_unpack_dictionary(side_metadata, size, frame_md);
}

int ff_decode_frame_props_from_pkt(const AVCodecContext *avctx,
                                  AVFrame *frame, const AVPacket *pkt)
{
   static const SideDataMap sd[] = {
       { AV_PKT_DATA_A53_CC,                     AV_FRAME_DATA_A53_CC },
       { AV_PKT_DATA_AFD,                        AV_FRAME_DATA_AFD },
       { AV_PKT_DATA_DYNAMIC_HDR10_PLUS,         AV_FRAME_DATA_DYNAMIC_HDR_PLUS },
       { AV_PKT_DATA_S12M_TIMECODE,              AV_FRAME_DATA_S12M_TIMECODE },
       { AV_PKT_DATA_SKIP_SAMPLES,               AV_FRAME_DATA_SKIP_SAMPLES },
       { AV_PKT_DATA_LCEVC,                      AV_FRAME_DATA_LCEVC },
       { AV_PKT_DATA_NB }
   };

   int ret = 0;

   frame->pts          = pkt->pts;
   frame->duration     = pkt->duration;
#if FF_API_FRAME_PKT
FF_DISABLE_DEPRECATION_WARNINGS
   frame->pkt_pos      = pkt->pos;
   frame->pkt_size     = pkt->size;
FF_ENABLE_DEPRECATION_WARNINGS
#endif

   ret = side_data_map(frame, pkt->side_data, pkt->side_data_elems, ff_sd_global_map);
   if (ret < 0)
       return ret;

   ret = side_data_map(frame, pkt->side_data, pkt->side_data_elems, sd);
   if (ret < 0)
       return ret;

   add_metadata_from_side_data(pkt, frame);

   if (pkt->flags & AV_PKT_FLAG_DISCARD) {
       frame->flags |= AV_FRAME_FLAG_DISCARD;
   }

   if (avctx->flags & AV_CODEC_FLAG_COPY_OPAQUE) {
       int ret = av_buffer_replace(&frame->opaque_ref, pkt->opaque_ref);
       if (ret < 0)
           return ret;
       frame->opaque = pkt->opaque;
   }

   return 0;
}

int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame)
{
   int ret;

   ret = side_data_map(frame, avctx->coded_side_data, avctx->nb_coded_side_data,
                       ff_sd_global_map);
   if (ret < 0)
       return ret;

   if (!(ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS)) {
       const AVPacket *pkt = avctx->internal->last_pkt_props;

       ret = ff_decode_frame_props_from_pkt(avctx, frame, pkt);
       if (ret < 0)
           return ret;
#if FF_API_FRAME_PKT
FF_DISABLE_DEPRECATION_WARNINGS
       frame->pkt_size = pkt->stream_index;
FF_ENABLE_DEPRECATION_WARNINGS
#endif
   }

   ret = fill_frame_props(avctx, frame);
   if (ret < 0)
       return ret;

   switch (avctx->codec->type) {
   case AVMEDIA_TYPE_VIDEO:
       if (frame->width && frame->height &&
           av_image_check_sar(frame->width, frame->height,
                              frame->sample_aspect_ratio) < 0) {
           av_log(avctx, AV_LOG_WARNING, "ignoring invalid SAR: %u/%u\n",
                  frame->sample_aspect_ratio.num,
                  frame->sample_aspect_ratio.den);
           frame->sample_aspect_ratio = (AVRational){ 0, 1 };
       }
       break;
   }
   return 0;
}

static void validate_avframe_allocation(AVCodecContext *avctx, AVFrame *frame)
{
   if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
       int i;
       int num_planes = av_pix_fmt_count_planes(frame->format);
       const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(frame->format);
       int flags = desc ? desc->flags : 0;
       if (num_planes == 1 && (flags & AV_PIX_FMT_FLAG_PAL))
           num_planes = 2;
       for (i = 0; i < num_planes; i++) {
           av_assert0(frame->data[i]);
       }
       // For formats without data like hwaccel allow unused pointers to be non-NULL.
       for (i = num_planes; num_planes > 0 && i < FF_ARRAY_ELEMS(frame->data); i++) {
           if (frame->data[i])
               av_log(avctx, AV_LOG_ERROR, "Buffer returned by get_buffer2() did not zero unused plane pointers\n");
           frame->data[i] = NULL;
       }
   }
}

static void decode_data_free(void *opaque, uint8_t *data)
{
   FrameDecodeData *fdd = (FrameDecodeData*)data;

   if (fdd->post_process_opaque_free)
       fdd->post_process_opaque_free(fdd->post_process_opaque);

   if (fdd->hwaccel_priv_free)
       fdd->hwaccel_priv_free(fdd->hwaccel_priv);

   av_freep(&fdd);
}

int ff_attach_decode_data(AVFrame *frame)
{
   AVBufferRef *fdd_buf;
   FrameDecodeData *fdd;

   av_assert1(!frame->private_ref);
   av_buffer_unref(&frame->private_ref);

   fdd = av_mallocz(sizeof(*fdd));
   if (!fdd)
       return AVERROR(ENOMEM);

   fdd_buf = av_buffer_create((uint8_t*)fdd, sizeof(*fdd), decode_data_free,
                              NULL, AV_BUFFER_FLAG_READONLY);
   if (!fdd_buf) {
       av_freep(&fdd);
       return AVERROR(ENOMEM);
   }

   frame->private_ref = fdd_buf;

   return 0;
}

static void update_frame_props(AVCodecContext *avctx, AVFrame *frame)
{
   AVCodecInternal    *avci = avctx->internal;
   DecodeContext        *dc = decode_ctx(avci);

   dc->lcevc_frame = dc->lcevc && avctx->codec_type == AVMEDIA_TYPE_VIDEO &&
                     av_frame_get_side_data(frame, AV_FRAME_DATA_LCEVC);

   if (dc->lcevc_frame) {
       dc->width     = frame->width;
       dc->height    = frame->height;
       frame->width  = frame->width  * 2 / FFMAX(frame->sample_aspect_ratio.den, 1);
       frame->height = frame->height * 2 / FFMAX(frame->sample_aspect_ratio.num, 1);
   }
}

static void attach_post_process_data(AVCodecContext *avctx, AVFrame *frame)
{
   AVCodecInternal    *avci = avctx->internal;
   DecodeContext        *dc = decode_ctx(avci);

   if (dc->lcevc_frame) {
       FrameDecodeData *fdd = (FrameDecodeData*)frame->private_ref->data;

       fdd->post_process_opaque = av_refstruct_ref(dc->lcevc);
       fdd->post_process_opaque_free = ff_lcevc_unref;
       fdd->post_process = ff_lcevc_process;

       frame->width  = dc->width;
       frame->height = dc->height;
   }
   dc->lcevc_frame = 0;
}

int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
{
   const FFHWAccel *hwaccel = ffhwaccel(avctx->hwaccel);
   int override_dimensions = 1;
   int ret;

   av_assert0(av_codec_is_decoder(avctx->codec));

   if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
       if ((unsigned)avctx->width > INT_MAX - STRIDE_ALIGN ||
           (ret = av_image_check_size2(FFALIGN(avctx->width, STRIDE_ALIGN), avctx->height, avctx->max_pixels, AV_PIX_FMT_NONE, 0, avctx)) < 0 || avctx->pix_fmt<0) {
           av_log(avctx, AV_LOG_ERROR, "video_get_buffer: image parameters invalid\n");
           ret = AVERROR(EINVAL);
           goto fail;
       }

       if (frame->width <= 0 || frame->height <= 0) {
           frame->width  = FFMAX(avctx->width,  AV_CEIL_RSHIFT(avctx->coded_width,  avctx->lowres));
           frame->height = FFMAX(avctx->height, AV_CEIL_RSHIFT(avctx->coded_height, avctx->lowres));
           override_dimensions = 0;
       }

       if (frame->data[0] || frame->data[1] || frame->data[2] || frame->data[3]) {
           av_log(avctx, AV_LOG_ERROR, "pic->data[*]!=NULL in get_buffer_internal\n");
           ret = AVERROR(EINVAL);
           goto fail;
       }
   } else if (avctx->codec_type == AVMEDIA_TYPE_AUDIO) {
       if (frame->nb_samples * (int64_t)avctx->ch_layout.nb_channels > avctx->max_samples) {
           av_log(avctx, AV_LOG_ERROR, "samples per frame %d, exceeds max_samples %"PRId64"\n", frame->nb_samples, avctx->max_samples);
           ret = AVERROR(EINVAL);
           goto fail;
       }
   }
   ret = ff_decode_frame_props(avctx, frame);
   if (ret < 0)
       goto fail;

   if (hwaccel) {
       if (hwaccel->alloc_frame) {
           ret = hwaccel->alloc_frame(avctx, frame);
           goto end;
       }
   } else {
       avctx->sw_pix_fmt = avctx->pix_fmt;
       update_frame_props(avctx, frame);
   }

   ret = avctx->get_buffer2(avctx, frame, flags);
   if (ret < 0)
       goto fail;

   validate_avframe_allocation(avctx, frame);

   ret = ff_attach_decode_data(frame);
   if (ret < 0)
       goto fail;

   attach_post_process_data(avctx, frame);

end:
   if (avctx->codec_type == AVMEDIA_TYPE_VIDEO && !override_dimensions &&
       !(ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_EXPORTS_CROPPING)) {
       frame->width  = avctx->width;
       frame->height = avctx->height;
   }

fail:
   if (ret < 0) {
       av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
       av_frame_unref(frame);
   }

   return ret;
}

static int reget_buffer_internal(AVCodecContext *avctx, AVFrame *frame, int flags)
{
   AVFrame *tmp;
   int ret;

   av_assert0(avctx->codec_type == AVMEDIA_TYPE_VIDEO);

   // make sure the discard flag does not persist
   frame->flags &= ~AV_FRAME_FLAG_DISCARD;

   if (frame->data[0] && (frame->width != avctx->width || frame->height != avctx->height || frame->format != avctx->pix_fmt)) {
       av_log(avctx, AV_LOG_WARNING, "Picture changed from size:%dx%d fmt:%s to size:%dx%d fmt:%s in reget buffer()\n",
              frame->width, frame->height, av_get_pix_fmt_name(frame->format), avctx->width, avctx->height, av_get_pix_fmt_name(avctx->pix_fmt));
       av_frame_unref(frame);
   }

   if (!frame->data[0])
       return ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF);

   av_frame_side_data_free(&frame->side_data, &frame->nb_side_data);

   if ((flags & FF_REGET_BUFFER_FLAG_READONLY) || av_frame_is_writable(frame))
       return ff_decode_frame_props(avctx, frame);

   tmp = av_frame_alloc();
   if (!tmp)
       return AVERROR(ENOMEM);

   av_frame_move_ref(tmp, frame);

   ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF);
   if (ret < 0) {
       av_frame_free(&tmp);
       return ret;
   }

   av_frame_copy(frame, tmp);
   av_frame_free(&tmp);

   return 0;
}

int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
{
   int ret = reget_buffer_internal(avctx, frame, flags);
   if (ret < 0)
       av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
   return ret;
}

typedef struct ProgressInternal {
   ThreadProgress progress;
   struct AVFrame *f;
} ProgressInternal;

static void check_progress_consistency(const ProgressFrame *f)
{
   av_assert1(!!f->f == !!f->progress);
   av_assert1(!f->progress || f->progress->f == f->f);
}

int ff_progress_frame_alloc(AVCodecContext *avctx, ProgressFrame *f)
{
   AVRefStructPool *pool = avctx->internal->progress_frame_pool;

   av_assert1(!f->f && !f->progress);

   f->progress = av_refstruct_pool_get(pool);
   if (!f->progress)
       return AVERROR(ENOMEM);

   f->f = f->progress->f;
   return 0;
}

int ff_progress_frame_get_buffer(AVCodecContext *avctx, ProgressFrame *f, int flags)
{
   int ret;

   check_progress_consistency(f);
   if (!f->f) {
       ret = ff_progress_frame_alloc(avctx, f);
       if (ret < 0)
           return ret;
   }

   ret = ff_thread_get_buffer(avctx, f->progress->f, flags);
   if (ret < 0) {
       f->f = NULL;
       av_refstruct_unref(&f->progress);
       return ret;
   }
   return 0;
}

void ff_progress_frame_ref(ProgressFrame *dst, const ProgressFrame *src)
{
   av_assert1(src->progress && src->f && src->f == src->progress->f);
   av_assert1(!dst->f && !dst->progress);
   dst->f = src->f;
   dst->progress = av_refstruct_ref(src->progress);
}

void ff_progress_frame_unref(ProgressFrame *f)
{
   check_progress_consistency(f);
   f->f = NULL;
   av_refstruct_unref(&f->progress);
}

void ff_progress_frame_replace(ProgressFrame *dst, const ProgressFrame *src)
{
   if (dst == src)
       return;
   ff_progress_frame_unref(dst);
   check_progress_consistency(src);
   if (src->f)
       ff_progress_frame_ref(dst, src);
}

void ff_progress_frame_report(ProgressFrame *f, int n)
{
   ff_thread_progress_report(&f->progress->progress, n);
}

void ff_progress_frame_await(const ProgressFrame *f, int n)
{
   ff_thread_progress_await(&f->progress->progress, n);
}

#if !HAVE_THREADS
enum ThreadingStatus ff_thread_sync_ref(AVCodecContext *avctx, size_t offset)
{
   return FF_THREAD_NO_FRAME_THREADING;
}
#endif /* !HAVE_THREADS */

static av_cold int progress_frame_pool_init_cb(AVRefStructOpaque opaque, void *obj)
{
   const AVCodecContext *avctx = opaque.nc;
   ProgressInternal *progress = obj;
   int ret;

   ret = ff_thread_progress_init(&progress->progress, avctx->active_thread_type & FF_THREAD_FRAME);
   if (ret < 0)
       return ret;

   progress->f = av_frame_alloc();
   if (!progress->f)
       return AVERROR(ENOMEM);

   return 0;
}

static void progress_frame_pool_reset_cb(AVRefStructOpaque unused, void *obj)
{
   ProgressInternal *progress = obj;

   ff_thread_progress_reset(&progress->progress);
   av_frame_unref(progress->f);
}

static av_cold void progress_frame_pool_free_entry_cb(AVRefStructOpaque opaque, void *obj)
{
   ProgressInternal *progress = obj;

   ff_thread_progress_destroy(&progress->progress);
   av_frame_free(&progress->f);
}

int ff_decode_preinit(AVCodecContext *avctx)
{
   AVCodecInternal *avci = avctx->internal;
   DecodeContext     *dc = decode_ctx(avci);
   int ret = 0;

   dc->initial_pict_type = AV_PICTURE_TYPE_NONE;
   if (avctx->codec_descriptor->props & AV_CODEC_PROP_INTRA_ONLY) {
       dc->intra_only_flag = AV_FRAME_FLAG_KEY;
       if (avctx->codec_type == AVMEDIA_TYPE_VIDEO)
           dc->initial_pict_type = AV_PICTURE_TYPE_I;
   }

   /* if the decoder init function was already called previously,
    * free the already allocated subtitle_header before overwriting it */
   av_freep(&avctx->subtitle_header);

   if (avctx->codec->max_lowres < avctx->lowres || avctx->lowres < 0) {
       av_log(avctx, AV_LOG_WARNING, "The maximum value for lowres supported by the decoder is %d\n",
              avctx->codec->max_lowres);
       avctx->lowres = avctx->codec->max_lowres;
   }
   if (avctx->sub_charenc) {
       if (avctx->codec_type != AVMEDIA_TYPE_SUBTITLE) {
           av_log(avctx, AV_LOG_ERROR, "Character encoding is only "
                  "supported with subtitles codecs\n");
           return AVERROR(EINVAL);
       } else if (avctx->codec_descriptor->props & AV_CODEC_PROP_BITMAP_SUB) {
           av_log(avctx, AV_LOG_WARNING, "Codec '%s' is bitmap-based, "
                  "subtitles character encoding will be ignored\n",
                  avctx->codec_descriptor->name);
           avctx->sub_charenc_mode = FF_SUB_CHARENC_MODE_DO_NOTHING;
       } else {
           /* input character encoding is set for a text based subtitle
            * codec at this point */
           if (avctx->sub_charenc_mode == FF_SUB_CHARENC_MODE_AUTOMATIC)
               avctx->sub_charenc_mode = FF_SUB_CHARENC_MODE_PRE_DECODER;

           if (avctx->sub_charenc_mode == FF_SUB_CHARENC_MODE_PRE_DECODER) {
#if CONFIG_ICONV
               iconv_t cd = iconv_open("UTF-8", avctx->sub_charenc);
               if (cd == (iconv_t)-1) {
                   ret = AVERROR(errno);
                   av_log(avctx, AV_LOG_ERROR, "Unable to open iconv context "
                          "with input character encoding \"%s\"\n", avctx->sub_charenc);
                   return ret;
               }
               iconv_close(cd);
#else
               av_log(avctx, AV_LOG_ERROR, "Character encoding subtitles "
                      "conversion needs a libavcodec built with iconv support "
                      "for this codec\n");
               return AVERROR(ENOSYS);
#endif
           }
       }
   }

   dc->pts_correction_num_faulty_pts =
   dc->pts_correction_num_faulty_dts = 0;
   dc->pts_correction_last_pts =
   dc->pts_correction_last_dts = INT64_MIN;

   if (   !CONFIG_GRAY && avctx->flags & AV_CODEC_FLAG_GRAY
       && avctx->codec_descriptor->type == AVMEDIA_TYPE_VIDEO)
       av_log(avctx, AV_LOG_WARNING,
              "gray decoding requested but not enabled at configuration time\n");
   if (avctx->flags2 & AV_CODEC_FLAG2_EXPORT_MVS) {
       avctx->export_side_data |= AV_CODEC_EXPORT_DATA_MVS;
   }

   if (avctx->nb_side_data_prefer_packet == 1 &&
       avctx->side_data_prefer_packet[0] == -1)
       dc->side_data_pref_mask = ~0ULL;
   else {
       for (unsigned i = 0; i < avctx->nb_side_data_prefer_packet; i++) {
           int val = avctx->side_data_prefer_packet[i];

           if (val < 0 || val >= AV_PKT_DATA_NB) {
               av_log(avctx, AV_LOG_ERROR, "Invalid side data type: %d\n", val);
               return AVERROR(EINVAL);
           }

           for (unsigned j = 0; ff_sd_global_map[j].packet < AV_PKT_DATA_NB; j++) {
               if (ff_sd_global_map[j].packet == val) {
                   val = ff_sd_global_map[j].frame;

                   // this code will need to be changed when we have more than
                   // 64 frame side data types
                   if (val >= 64) {
                       av_log(avctx, AV_LOG_ERROR, "Side data type too big\n");
                       return AVERROR_BUG;
                   }

                   dc->side_data_pref_mask |= 1ULL << val;
               }
           }
       }
   }

   avci->in_pkt         = av_packet_alloc();
   avci->last_pkt_props = av_packet_alloc();
   if (!avci->in_pkt || !avci->last_pkt_props)
       return AVERROR(ENOMEM);

   if (ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_USES_PROGRESSFRAMES) {
       avci->progress_frame_pool =
           av_refstruct_pool_alloc_ext(sizeof(ProgressInternal),
                                       AV_REFSTRUCT_POOL_FLAG_FREE_ON_INIT_ERROR,
                                       avctx, progress_frame_pool_init_cb,
                                       progress_frame_pool_reset_cb,
                                       progress_frame_pool_free_entry_cb, NULL);
       if (!avci->progress_frame_pool)
           return AVERROR(ENOMEM);
   }
   ret = decode_bsfs_init(avctx);
   if (ret < 0)
       return ret;

   if (!(avctx->export_side_data & AV_CODEC_EXPORT_DATA_ENHANCEMENTS)) {
       ret = ff_lcevc_alloc(&dc->lcevc);
       if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))
           return ret;
   }

#if FF_API_DROPCHANGED
   if (avctx->flags & AV_CODEC_FLAG_DROPCHANGED)
       av_log(avctx, AV_LOG_WARNING, "The dropchanged flag is deprecated.\n");
#endif

   return 0;
}

/**
* Check side data preference and clear existing side data from frame
* if needed.
*
* @retval 0 side data of this type can be added to frame
* @retval 1 side data of this type should not be added to frame
*/
static int side_data_pref(const AVCodecContext *avctx, AVFrameSideData ***sd,
                         int *nb_sd, enum AVFrameSideDataType type)
{
   DecodeContext *dc = decode_ctx(avctx->internal);

   // Note: could be skipped for `type` without corresponding packet sd
   if (av_frame_side_data_get(*sd, *nb_sd, type)) {
       if (dc->side_data_pref_mask & (1ULL << type))
           return 1;
       av_frame_side_data_remove(sd, nb_sd, type);
   }

   return 0;
}


int ff_frame_new_side_data(const AVCodecContext *avctx, AVFrame *frame,
                          enum AVFrameSideDataType type, size_t size,
                          AVFrameSideData **psd)
{
   AVFrameSideData *sd;

   if (side_data_pref(avctx, &frame->side_data, &frame->nb_side_data, type)) {
       if (psd)
           *psd = NULL;
       return 0;
   }

   sd = av_frame_new_side_data(frame, type, size);
   if (psd)
       *psd = sd;

   return sd ? 0 : AVERROR(ENOMEM);
}

int ff_frame_new_side_data_from_buf_ext(const AVCodecContext *avctx,
                                       AVFrameSideData ***sd, int *nb_sd,
                                       enum AVFrameSideDataType type,
                                       AVBufferRef **buf)
{
   int ret = 0;

   if (side_data_pref(avctx, sd, nb_sd, type))
       goto finish;

   if (!av_frame_side_data_add(sd, nb_sd, type, buf, 0))
       ret = AVERROR(ENOMEM);

finish:
   av_buffer_unref(buf);

   return ret;
}

int ff_frame_new_side_data_from_buf(const AVCodecContext *avctx,
                                   AVFrame *frame, enum AVFrameSideDataType type,
                                   AVBufferRef **buf)
{
   return ff_frame_new_side_data_from_buf_ext(avctx,
                                              &frame->side_data, &frame->nb_side_data,
                                              type, buf);
}

int ff_decode_mastering_display_new_ext(const AVCodecContext *avctx,
                                       AVFrameSideData ***sd, int *nb_sd,
                                       struct AVMasteringDisplayMetadata **mdm)
{
   AVBufferRef *buf;
   size_t size;

   if (side_data_pref(avctx, sd, nb_sd, AV_FRAME_DATA_MASTERING_DISPLAY_METADATA)) {
       *mdm = NULL;
       return 0;
   }

   *mdm = av_mastering_display_metadata_alloc_size(&size);
   if (!*mdm)
       return AVERROR(ENOMEM);

   buf = av_buffer_create((uint8_t *)*mdm, size, NULL, NULL, 0);
   if (!buf) {
       av_freep(mdm);
       return AVERROR(ENOMEM);
   }

   if (!av_frame_side_data_add(sd, nb_sd, AV_FRAME_DATA_MASTERING_DISPLAY_METADATA,
                               &buf, 0)) {
       *mdm = NULL;
       av_buffer_unref(&buf);
       return AVERROR(ENOMEM);
   }

   return 0;
}

int ff_decode_mastering_display_new(const AVCodecContext *avctx, AVFrame *frame,
                                   AVMasteringDisplayMetadata **mdm)
{
   if (side_data_pref(avctx, &frame->side_data, &frame->nb_side_data,
                      AV_FRAME_DATA_MASTERING_DISPLAY_METADATA)) {
       *mdm = NULL;
       return 0;
   }

   *mdm = av_mastering_display_metadata_create_side_data(frame);
   return *mdm ? 0 : AVERROR(ENOMEM);
}

int ff_decode_content_light_new_ext(const AVCodecContext *avctx,
                                   AVFrameSideData ***sd, int *nb_sd,
                                   AVContentLightMetadata **clm)
{
   AVBufferRef *buf;
   size_t size;

   if (side_data_pref(avctx, sd, nb_sd, AV_FRAME_DATA_CONTENT_LIGHT_LEVEL)) {
       *clm = NULL;
       return 0;
   }

   *clm = av_content_light_metadata_alloc(&size);
   if (!*clm)
       return AVERROR(ENOMEM);

   buf = av_buffer_create((uint8_t *)*clm, size, NULL, NULL, 0);
   if (!buf) {
       av_freep(clm);
       return AVERROR(ENOMEM);
   }

   if (!av_frame_side_data_add(sd, nb_sd, AV_FRAME_DATA_CONTENT_LIGHT_LEVEL,
                               &buf, 0)) {
       *clm = NULL;
       av_buffer_unref(&buf);
       return AVERROR(ENOMEM);
   }

   return 0;
}

int ff_decode_content_light_new(const AVCodecContext *avctx, AVFrame *frame,
                               AVContentLightMetadata **clm)
{
   if (side_data_pref(avctx, &frame->side_data, &frame->nb_side_data,
                      AV_FRAME_DATA_CONTENT_LIGHT_LEVEL)) {
       *clm = NULL;
       return 0;
   }

   *clm = av_content_light_metadata_create_side_data(frame);
   return *clm ? 0 : AVERROR(ENOMEM);
}

int ff_copy_palette(void *dst, const AVPacket *src, void *logctx)
{
   size_t size;
   const void *pal = av_packet_get_side_data(src, AV_PKT_DATA_PALETTE, &size);

   if (pal && size == AVPALETTE_SIZE) {
       memcpy(dst, pal, AVPALETTE_SIZE);
       return 1;
   } else if (pal) {
       av_log(logctx, AV_LOG_ERROR,
              "Palette size %"SIZE_SPECIFIER" is wrong\n", size);
   }
   return 0;
}

int ff_hwaccel_frame_priv_alloc(AVCodecContext *avctx, void **hwaccel_picture_private)
{
   const FFHWAccel *hwaccel = ffhwaccel(avctx->hwaccel);

   if (!hwaccel || !hwaccel->frame_priv_data_size)
       return 0;

   av_assert0(!*hwaccel_picture_private);

   if (hwaccel->free_frame_priv) {
       AVHWFramesContext *frames_ctx;

       if (!avctx->hw_frames_ctx)
           return AVERROR(EINVAL);

       frames_ctx = (AVHWFramesContext *) avctx->hw_frames_ctx->data;
       *hwaccel_picture_private = av_refstruct_alloc_ext(hwaccel->frame_priv_data_size, 0,
                                                         frames_ctx->device_ctx,
                                                         hwaccel->free_frame_priv);
   } else {
       *hwaccel_picture_private = av_refstruct_allocz(hwaccel->frame_priv_data_size);
   }

   if (!*hwaccel_picture_private)
       return AVERROR(ENOMEM);

   return 0;
}

void ff_decode_flush_buffers(AVCodecContext *avctx)
{
   AVCodecInternal *avci = avctx->internal;
   DecodeContext     *dc = decode_ctx(avci);

   av_packet_unref(avci->last_pkt_props);
   av_packet_unref(avci->in_pkt);

   dc->pts_correction_last_pts =
   dc->pts_correction_last_dts = INT64_MIN;

   if (avci->bsf)
       av_bsf_flush(avci->bsf);

   dc->nb_draining_errors = 0;
   dc->draining_started   = 0;
}

AVCodecInternal *ff_decode_internal_alloc(void)
{
   return av_mallocz(sizeof(DecodeContext));
}

void ff_decode_internal_sync(AVCodecContext *dst, const AVCodecContext *src)
{
   const DecodeContext *src_dc = decode_ctx(src->internal);
   DecodeContext *dst_dc = decode_ctx(dst->internal);

   av_refstruct_replace(&dst_dc->lcevc, src_dc->lcevc);
}

void ff_decode_internal_uninit(AVCodecContext *avctx)
{
   AVCodecInternal *avci = avctx->internal;
   DecodeContext *dc = decode_ctx(avci);

   av_refstruct_unref(&dc->lcevc);
}