AV_CODEC_ID_FIRST_UNKNOWN 3746 libavcodec/utils.c     else if (codec_id < AV_CODEC_ID_FIRST_UNKNOWN)
AV_CODEC_ID_FIRST_UNKNOWN 1508 libavformat/mpegts.c             else if (st->codec->codec_id < AV_CODEC_ID_FIRST_UNKNOWN)