Re: [FFmpeg-devel] [PATCH v11 2/6] avformat/flvdec: support demux hevc in enhanced flv

[Lance Wang <lance.lmwang@gmail.com>]

On Fri, Jun 2, 2023 at 3:32 PM Steven Liu <lq@chinaffmpeg.org> wrote:

> Signed-off-by: Steven Liu <lq@chinaffmpeg.org>
> ---
>  libavformat/flvdec.c | 58 ++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 50 insertions(+), 8 deletions(-)
>
> diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
> index d83edff727..c8e6cadf1c 100644
> --- a/libavformat/flvdec.c
> +++ b/libavformat/flvdec.c
> @@ -79,6 +79,8 @@ typedef struct FLVContext {
>      int64_t last_ts;
>      int64_t time_offset;
>      int64_t time_pos;
> +
> +    uint8_t exheader;
>  } FLVContext;
>
>  /* AMF date type */
> @@ -302,13 +304,25 @@ static void flv_set_audio_codec(AVFormatContext *s,
> AVStream *astream,
>      }
>  }
>
> -static int flv_same_video_codec(AVCodecParameters *vpar, int flags)
> +static int flv_same_video_codec(AVFormatContext *s, AVCodecParameters
> *vpar, int flags)
>  {
>      int flv_codecid = flags & FLV_VIDEO_CODECID_MASK;
> +    FLVContext *flv = s->priv_data;
>
>      if (!vpar->codec_id && !vpar->codec_tag)
>          return 1;
>
> +    if (flv->exheader) {
> +        uint8_t *codec_id_str = (uint8_t *)s->pb->buf_ptr;
> +        uint32_t codec_id = codec_id_str[3] | codec_id_str[2] << 8 |
> codec_id_str[1] << 16 | codec_id_str[0] << 24;
> +        switch(codec_id) {
> +            case MKBETAG('h', 'v', 'c', '1'):
> +                return vpar->codec_id == AV_CODEC_ID_HEVC;
> +            default:
> +                break;
> +        }
> +    }
> +
>      switch (flv_codecid) {
>      case FLV_CODECID_H263:
>          return vpar->codec_id == AV_CODEC_ID_FLV1;
> @@ -331,9 +345,24 @@ static int flv_set_video_codec(AVFormatContext *s,
> AVStream *vstream,
>                                 int flv_codecid, int read)
>  {
>      FFStream *const vstreami = ffstream(vstream);
> +    FLVContext *flv = s->priv_data;
>      int ret = 0;
>      AVCodecParameters *par = vstream->codecpar;
>      enum AVCodecID old_codec_id = vstream->codecpar->codec_id;
> +    flv_codecid &= FLV_VIDEO_CODECID_MASK;
> +
> +    if (flv->exheader) {
> +        uint32_t codec_id = avio_rb32(s->pb);
> +
> +        switch(codec_id) {
> +            case MKBETAG('h', 'v', 'c', '1'):
> +                par->codec_id = AV_CODEC_ID_HEVC;
> +                vstreami->need_parsing = AVSTREAM_PARSE_HEADERS;
> +                return 4;
> +            default:
> +                break;
> +        }
> +    }
>      switch (flv_codecid) {
>      case FLV_CODECID_H263:
>          par->codec_id = AV_CODEC_ID_FLV1;
> @@ -796,6 +825,7 @@ static int flv_read_header(AVFormatContext *s)
>      s->start_time = 0;
>      flv->sum_flv_tag_size = 0;
>      flv->last_keyframe_stream_index = -1;
> +    flv->exheader = 0;
>
>      return 0;
>  }
> @@ -1071,6 +1101,11 @@ retry:
>      } else if (type == FLV_TAG_TYPE_VIDEO) {
>          stream_type = FLV_STREAM_TYPE_VIDEO;
>          flags    = avio_r8(s->pb);
> +        /*
> +         * Reference Enhancing FLV 2023-03-v1.0.0-B.8
> +         *
> https://github.com/veovera/enhanced-rtmp/blob/main/enhanced-rtmp-v1.pdf
> +         * */
> +        flv->exheader = (flags >> 7) & 1;
>          size--;
>          if ((flags & FLV_VIDEO_FRAMETYPE_MASK) ==
> FLV_FRAME_VIDEO_INFO_CMD)
>              goto skip;
> @@ -1129,7 +1164,7 @@ skip:
>                  break;
>          } else if (stream_type == FLV_STREAM_TYPE_VIDEO) {
>              if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
> -                (s->video_codec_id || flv_same_video_codec(st->codecpar,
> flags)))
> +                (s->video_codec_id || flv_same_video_codec(s,
> st->codecpar, flags)))
>                  break;
>          } else if (stream_type == FLV_STREAM_TYPE_SUBTITLE) {
>              if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE)
> @@ -1230,7 +1265,7 @@ retry_duration:
>              avcodec_parameters_free(&par);
>          }
>      } else if (stream_type == FLV_STREAM_TYPE_VIDEO) {
> -        int ret = flv_set_video_codec(s, st, flags &
> FLV_VIDEO_CODECID_MASK, 1);
> +        int ret = flv_set_video_codec(s, st, flags, 1);
>          if (ret < 0)
>              return ret;
>          size -= ret;
> @@ -1242,16 +1277,23 @@ retry_duration:
>
>      if (st->codecpar->codec_id == AV_CODEC_ID_AAC ||
>          st->codecpar->codec_id == AV_CODEC_ID_H264 ||
> -        st->codecpar->codec_id == AV_CODEC_ID_MPEG4) {
> -        int type = avio_r8(s->pb);
> -        size--;
> +        st->codecpar->codec_id == AV_CODEC_ID_MPEG4 ||
> +        st->codecpar->codec_id == AV_CODEC_ID_HEVC) {
> +        int type = 0;
>

int type;

+        if (flv->exheader && stream_type == FLV_STREAM_TYPE_VIDEO) {
> +            type = flags & 0x0F;
> +        } else {
> +            type = avio_r8(s->pb);
> +            size--;
> +        }
>
>          if (size < 0) {
>              ret = AVERROR_INVALIDDATA;
>              goto leave;
>          }
>
> -        if (st->codecpar->codec_id == AV_CODEC_ID_H264 ||
> st->codecpar->codec_id == AV_CODEC_ID_MPEG4) {
> +        if (st->codecpar->codec_id == AV_CODEC_ID_H264 ||
> st->codecpar->codec_id == AV_CODEC_ID_MPEG4 ||
> +            (st->codecpar->codec_id == AV_CODEC_ID_HEVC && type ==
> PacketTypeCodedFrames)) {
>              // sign extension
>              int32_t cts = (avio_rb24(s->pb) + 0xff800000) ^ 0xff800000;
>              pts = av_sat_add64(dts, cts);
> @@ -1267,7 +1309,7 @@ retry_duration:
>              }
>          }
>          if (type == 0 && (!st->codecpar->extradata ||
> st->codecpar->codec_id == AV_CODEC_ID_AAC ||
> -            st->codecpar->codec_id == AV_CODEC_ID_H264)) {
> +            st->codecpar->codec_id == AV_CODEC_ID_H264 ||
> st->codecpar->codec_id == AV_CODEC_ID_HEVC)) {
>              AVDictionaryEntry *t;
>
>              if (st->codecpar->extradata) {
> --
> 2.40.0
>
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