Get codec extradata from video frame

get_codec_extradata.c

static uint8_t *
mp4serv_get_codec_extradata (EdcBuf  *frame,
                             int     *extradata_size)
{
  AVBSFContext *bsf;
  const AVBitStreamFilter *f;
  const enum AVCodecID *ids;
  AVPacket *dst_pkt;
  int avcodec_id;
  int found;
  int ret;
  AVPacket pkt;
  AVPacket *pkt_ref;
  uint8_t *data;

  data = NULL;
  if (extradata_size)
    *extradata_size = 0;

  f = av_bsf_get_by_name ("extract_extradata");
  if (!f || !f->codec_ids)
    return data;

  avcodec_id = edc_codec_lookup_avcodec_id (frame->codec_id);

  found = 0;
  for (ids = f->codec_ids; *ids != AV_CODEC_ID_NONE; ids++)
    {
      if (*ids == avcodec_id)
        {
          found = 1;
          break;
        }
    }

  if (!found)
    return data;

  bsf = NULL;
  ret = av_bsf_alloc (f, &bsf);
  if (ret < 0)
    return data;

  bsf->par_in->codec_id = avcodec_id;
  ret = av_bsf_init (bsf);
  if (ret < 0)
    {
      av_bsf_free (&bsf);

      return data;
    }

  dst_pkt = av_packet_alloc ();
  pkt_ref = dst_pkt;

  av_init_packet (&pkt);
  pkt.data = (uint8_t *) frame->data;
  pkt.size = frame->len;
  if (frame->flags & EDC_BUF_FLAG_KEY_FRAME)
    pkt.flags |= AV_PKT_FLAG_KEY;

  ret = av_packet_ref (pkt_ref, &pkt);
  if (ret < 0)
    goto end_of_extract_extradata;

  ret = av_bsf_send_packet (bsf, pkt_ref);
  if (ret < 0)
    {
      av_packet_unref (pkt_ref);

      goto end_of_extract_extradata;
    }

  ret = 0;
  while (ret >= 0)
    {
      uint8_t *extra;
      int extra_size;

      ret = av_bsf_receive_packet (bsf, pkt_ref);
      if (ret < 0)
        {
          if (ret != AVERROR (EAGAIN) && ret != AVERROR_EOF)
            break;

          continue;
        }

      extra = av_packet_get_side_data (pkt_ref,
                                       AV_PKT_DATA_NEW_EXTRADATA,
                                       &extra_size);
      if (extra && extra_size > 0)
        {
          data = g_malloc0 (extra_size + AV_INPUT_BUFFER_PADDING_SIZE);
          memcpy (data, extra, extra_size);
          if (extradata_size)
            *extradata_size = extra_size;

          av_packet_unref (pkt_ref);
          break;
        }

      av_packet_unref (pkt_ref);
    }

end_of_extract_extradata:

  av_bsf_free (&bsf);
  av_packet_free (&dst_pkt);

  return data;
}