Re: [FFmpeg-devel] [PATCH] avformat/flvdec: handle exheader fourcc correctly in metadata

From: Steven Liu <lingjiujianke@gmail.com>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Cc: Marton Balint <cus@passwd.hu>
Subject: Re: [FFmpeg-devel] [PATCH] avformat/flvdec: handle exheader fourcc correctly in metadata
Date: Wed, 2 Aug 2023 09:44:41 +0800
Message-ID: <CADxeRwnDAfYWv1Ucig+ZZgdJsQHzhVxpkaFGJcCdjwjRptTsLQ@mail.gmail.com> (raw)
In-Reply-To: <20230729174900.25789-1-cus@passwd.hu>

Marton Balint <cus@passwd.hu> 于2023年7月30日周日 01:49写道：
>
> In metadata fourcc is carried in the AMF number, not as binary.
>
> Partially based on a patch by Steven Liu.
>
> Signed-off-by: Marton Balint <cus@passwd.hu>
> ---
>  libavformat/flvdec.c | 76 +++++++++++++++++---------------------------
>  1 file changed, 30 insertions(+), 46 deletions(-)
>
> diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
> index 3fe21622f7..b904029ba5 100644
> --- a/libavformat/flvdec.c
> +++ b/libavformat/flvdec.c
> @@ -304,30 +304,18 @@ static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream,
>      }
>  }
>
> -static int flv_same_video_codec(AVFormatContext *s, AVCodecParameters *vpar, int flags)
> +static int flv_same_video_codec(AVFormatContext *s, AVCodecParameters *vpar, uint32_t flv_codecid)
>  {
> -    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;
> -            case MKBETAG('a', 'v', '0', '1'):
> -                return vpar->codec_id == AV_CODEC_ID_AV1;
> -            case MKBETAG('v', 'p', '0', '9'):
> -                return vpar->codec_id == AV_CODEC_ID_VP9;
> -            default:
> -                break;
> -        }
> -    }
> -
>      switch (flv_codecid) {
> +    case MKBETAG('h', 'v', 'c', '1'):
> +        return vpar->codec_id == AV_CODEC_ID_HEVC;
> +    case MKBETAG('a', 'v', '0', '1'):
> +        return vpar->codec_id == AV_CODEC_ID_AV1;
> +    case MKBETAG('v', 'p', '0', '9'):
> +        return vpar->codec_id == AV_CODEC_ID_VP9;
>      case FLV_CODECID_H263:
>          return vpar->codec_id == AV_CODEC_ID_FLV1;
>      case FLV_CODECID_SCREEN:
> @@ -346,36 +334,26 @@ static int flv_same_video_codec(AVFormatContext *s, AVCodecParameters *vpar, int
>  }
>
>  static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream,
> -                               int flv_codecid, int read)
> +                               uint32_t 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;
> -            case MKBETAG('a', 'v', '0', '1'):
> -                par->codec_id = AV_CODEC_ID_AV1;
> -                vstreami->need_parsing = AVSTREAM_PARSE_HEADERS;
> -                return 4;
> -            case MKBETAG('v', 'p', '0', '9'):
> -                par->codec_id = AV_CODEC_ID_VP9;
> -                vstreami->need_parsing = AVSTREAM_PARSE_HEADERS;
> -                return 4;
> -            default:
> -                break;
> -        }
> -    }
> -    switch (flv_codecid) {
> +
> +    switch(flv_codecid) {
> +    case MKBETAG('h', 'v', 'c', '1'):
> +        par->codec_id = AV_CODEC_ID_HEVC;
> +        vstreami->need_parsing = AVSTREAM_PARSE_HEADERS;
> +        break;
> +    case MKBETAG('a', 'v', '0', '1'):
> +        par->codec_id = AV_CODEC_ID_AV1;
> +        vstreami->need_parsing = AVSTREAM_PARSE_HEADERS;
> +        break;
> +    case MKBETAG('v', 'p', '0', '9'):
> +        par->codec_id = AV_CODEC_ID_VP9;
> +        vstreami->need_parsing = AVSTREAM_PARSE_HEADERS;
> +        break;
>      case FLV_CODECID_H263:
>          par->codec_id = AV_CODEC_ID_FLV1;
>          break;
> @@ -1065,6 +1043,7 @@ static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
>      AVStream *st    = NULL;
>      int last = -1;
>      int orig_size;
> +    uint32_t video_codec_id = 0;
>
>  retry:
>      /* pkt size is repeated at end. skip it */
> @@ -1111,12 +1090,17 @@ retry:
>      } else if (type == FLV_TAG_TYPE_VIDEO) {
>          stream_type = FLV_STREAM_TYPE_VIDEO;
>          flags    = avio_r8(s->pb);
> +        video_codec_id = flags & FLV_VIDEO_CODECID_MASK;
>          /*
>           * 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 (flv->exheader) {
> +            video_codec_id = avio_rb32(s->pb);
> +            size -= 4;
> +        }
>          if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_VIDEO_INFO_CMD)
>              goto skip;
>      } else if (type == FLV_TAG_TYPE_META) {
> @@ -1174,7 +1158,7 @@ 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(s, st->codecpar, flags)))
> +                (s->video_codec_id || flv_same_video_codec(s, st->codecpar, video_codec_id)))
>                  break;
>          } else if (stream_type == FLV_STREAM_TYPE_SUBTITLE) {
>              if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE)
> @@ -1275,7 +1259,7 @@ retry_duration:
>              avcodec_parameters_free(&par);
>          }
>      } else if (stream_type == FLV_STREAM_TYPE_VIDEO) {
> -        int ret = flv_set_video_codec(s, st, flags, 1);
> +        int ret = flv_set_video_codec(s, st, video_codec_id, 1);
>          if (ret < 0)
>              return ret;
>          size -= ret;
> --
> 2.35.3
>
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should be ok

Thanks
Steven
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