Re: [FFmpeg-devel] [PATCH v11 1/6] avformat/flvenc: support mux hevc in enhanced flv

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

On Fri, Jun 2, 2023 at 3:31 PM Steven Liu <lq@chinaffmpeg.org> wrote:

> Signed-off-by: Steven Liu <lq@chinaffmpeg.org>
> ---
>  libavformat/Makefile |  2 +-
>  libavformat/flv.h    | 15 +++++++++++++++
>  libavformat/flvenc.c | 41 +++++++++++++++++++++++++++++++----------
>  3 files changed, 47 insertions(+), 11 deletions(-)
>
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index f8ad7c6a11..1ef3d15467 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -214,7 +214,7 @@ OBJS-$(CONFIG_FLAC_MUXER)                += flacenc.o
> flacenc_header.o \
>  OBJS-$(CONFIG_FLIC_DEMUXER)              += flic.o
>  OBJS-$(CONFIG_FLV_DEMUXER)               += flvdec.o
>  OBJS-$(CONFIG_LIVE_FLV_DEMUXER)          += flvdec.o
> -OBJS-$(CONFIG_FLV_MUXER)                 += flvenc.o avc.o
> +OBJS-$(CONFIG_FLV_MUXER)                 += flvenc.o avc.o hevc.o
>  OBJS-$(CONFIG_FOURXM_DEMUXER)            += 4xm.o
>  OBJS-$(CONFIG_FRAMECRC_MUXER)            += framecrcenc.o framehash.o
>  OBJS-$(CONFIG_FRAMEHASH_MUXER)           += hashenc.o framehash.o
> diff --git a/libavformat/flv.h b/libavformat/flv.h
> index 3571b90279..91e0a4140c 100644
> --- a/libavformat/flv.h
> +++ b/libavformat/flv.h
> @@ -35,6 +35,12 @@
>
>  #define FLV_VIDEO_FRAMETYPE_OFFSET   4
>
> +/* Extended VideoTagHeader
> + * defined in reference link:
> + *
> https://github.com/veovera/enhanced-rtmp/blob/main/enhanced-rtmp-v1.pdf
> + * */
> +#define FLV_IS_EX_HEADER          0x80
> +
>  /* bitmasks to isolate specific values */
>  #define FLV_AUDIO_CHANNEL_MASK    0x01
>  #define FLV_AUDIO_SAMPLESIZE_MASK 0x02
> @@ -112,6 +118,15 @@ enum {
>      FLV_CODECID_MPEG4   = 9,
>  };
>
> +enum {
> +    PacketTypeSequenceStart         = 0,
> +    PacketTypeCodedFrames           = 1,
> +    PacketTypeSequenceEnd           = 2,
> +    PacketTypeCodedFramesX          = 3,
> +    PacketTypeMetadata              = 4,
> +    PacketTypeMPEG2TSSequenceStart  = 5,
> +};
> +
>

format and align the "="?



>  enum {
>      FLV_FRAME_KEY            = 1 << FLV_VIDEO_FRAMETYPE_OFFSET, ///< key
> frame (for AVC, a seekable frame)
>      FLV_FRAME_INTER          = 2 << FLV_VIDEO_FRAMETYPE_OFFSET, ///<
> inter frame (for AVC, a non-seekable frame)
> diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
> index 721f062811..aed0946a2e 100644
> --- a/libavformat/flvenc.c
> +++ b/libavformat/flvenc.c
> @@ -28,6 +28,7 @@
>  #include "libavcodec/mpeg4audio.h"
>  #include "avio.h"
>  #include "avc.h"
> +#include "hevc.h"
>  #include "avformat.h"
>  #include "flv.h"
>  #include "internal.h"
> @@ -46,6 +47,7 @@ static const AVCodecTag flv_video_codec_ids[] = {
>      { AV_CODEC_ID_VP6,      FLV_CODECID_VP6 },
>      { AV_CODEC_ID_VP6A,     FLV_CODECID_VP6A },
>      { AV_CODEC_ID_H264,     FLV_CODECID_H264 },
> +    { AV_CODEC_ID_HEVC,     MKBETAG('h', 'v', 'c', '1') },
>      { AV_CODEC_ID_NONE,     0 }
>  };
>
> @@ -489,7 +491,7 @@ static void flv_write_codec_header(AVFormatContext* s,
> AVCodecParameters* par, i
>      FLVContext *flv = s->priv_data;
>
>      if (par->codec_id == AV_CODEC_ID_AAC || par->codec_id ==
> AV_CODEC_ID_H264
> -            || par->codec_id == AV_CODEC_ID_MPEG4) {
> +            || par->codec_id == AV_CODEC_ID_MPEG4 || par->codec_id ==
> AV_CODEC_ID_HEVC) {
>          int64_t pos;
>          avio_w8(pb,
>                  par->codec_type == AVMEDIA_TYPE_VIDEO ?
> @@ -532,10 +534,19 @@ static void flv_write_codec_header(AVFormatContext*
> s, AVCodecParameters* par, i
>              }
>              avio_write(pb, par->extradata, par->extradata_size);
>          } else {
> -            avio_w8(pb, par->codec_tag | FLV_FRAME_KEY); // flags
> -            avio_w8(pb, 0); // AVC sequence header
> -            avio_wb24(pb, 0); // composition time
> -            ff_isom_write_avcc(pb, par->extradata, par->extradata_size);
> +            if (par->codec_id == AV_CODEC_ID_HEVC) {
> +                avio_w8(pb, FLV_IS_EX_HEADER | PacketTypeSequenceStart |
> FLV_FRAME_KEY); // ExVideoTagHeader mode with PacketTypeSequenceStart
> +                avio_write(pb, "hvc1", 4);
>
 ff_isom_write_hvcc(pb, par->extradata, par->extradata_size, 0);


> +            } else {
> +                avio_w8(pb, par->codec_tag | FLV_FRAME_KEY); // flags
> +                avio_w8(pb, 0); // AVC sequence header
> +                avio_wb24(pb, 0); // composition time
>

ff_isom_write_avcc(pb, par->extradata, par->extradata_size);


> +            }
> +
> +            if (par->codec_id == AV_CODEC_ID_HEVC)
> +                ff_isom_write_hvcc(pb, par->extradata,
> par->extradata_size, 0);
> +            else
> +                ff_isom_write_avcc(pb, par->extradata,
> par->extradata_size);
>

merge the if else?

         }
>          data_size = avio_tell(pb) - pos;
>          avio_seek(pb, -data_size - 10, SEEK_CUR);
> @@ -821,6 +832,7 @@ static int flv_write_packet(AVFormatContext *s,
> AVPacket *pkt)
>      unsigned ts;
>      int size = pkt->size;
>      uint8_t *data = NULL;
> +    uint8_t frametype = pkt->flags & AV_PKT_FLAG_KEY ? FLV_FRAME_KEY :
> FLV_FRAME_INTER;
>      int flags = -1, flags_size, ret = 0;
>      int64_t cur_offset = avio_tell(pb);
>
> @@ -832,13 +844,13 @@ static int flv_write_packet(AVFormatContext *s,
> AVPacket *pkt)
>      if (par->codec_id == AV_CODEC_ID_VP6F || par->codec_id ==
> AV_CODEC_ID_VP6A ||
>          par->codec_id == AV_CODEC_ID_VP6  || par->codec_id ==
> AV_CODEC_ID_AAC)
>          flags_size = 2;
> -    else if (par->codec_id == AV_CODEC_ID_H264 || par->codec_id ==
> AV_CODEC_ID_MPEG4)
> +    else if (par->codec_id == AV_CODEC_ID_H264 || par->codec_id ==
> AV_CODEC_ID_MPEG4 || par->codec_id == AV_CODEC_ID_HEVC)
>          flags_size = 5;
>      else
>          flags_size = 1;
>
>      if (par->codec_id == AV_CODEC_ID_AAC || par->codec_id ==
> AV_CODEC_ID_H264
> -            || par->codec_id == AV_CODEC_ID_MPEG4) {
> +            || par->codec_id == AV_CODEC_ID_MPEG4 || par->codec_id ==
> AV_CODEC_ID_HEVC) {
>          size_t side_size;
>          uint8_t *side = av_packet_get_side_data(pkt,
> AV_PKT_DATA_NEW_EXTRADATA, &side_size);
>          if (side && side_size > 0 && (side_size != par->extradata_size ||
> memcmp(side, par->extradata, side_size))) {
> @@ -858,7 +870,7 @@ static int flv_write_packet(AVFormatContext *s,
> AVPacket *pkt)
>                 "Packets are not in the proper order with respect to
> DTS\n");
>          return AVERROR(EINVAL);
>      }
> -    if (par->codec_id == AV_CODEC_ID_H264 || par->codec_id ==
> AV_CODEC_ID_MPEG4) {
> +    if (par->codec_id == AV_CODEC_ID_H264 || par->codec_id ==
> AV_CODEC_ID_MPEG4 || par->codec_id == AV_CODEC_ID_HEVC) {
>          if (pkt->pts == AV_NOPTS_VALUE) {
>              av_log(s, AV_LOG_ERROR, "Packet is missing PTS\n");
>              return AVERROR(EINVAL);
> @@ -881,7 +893,7 @@ static int flv_write_packet(AVFormatContext *s,
> AVPacket *pkt)
>
>          flags = ff_codec_get_tag(flv_video_codec_ids, par->codec_id);
>
> -        flags |= pkt->flags & AV_PKT_FLAG_KEY ? FLV_FRAME_KEY :
> FLV_FRAME_INTER;
> +        flags |= frametype;
>          break;
>      case AVMEDIA_TYPE_AUDIO:
>          flags = get_audio_flags(s, par);
> @@ -903,6 +915,10 @@ static int flv_write_packet(AVFormatContext *s,
> AVPacket *pkt)
>          if (par->extradata_size > 0 && *(uint8_t*)par->extradata != 1)
>              if ((ret = ff_avc_parse_nal_units_buf(pkt->data, &data,
> &size)) < 0)
>                  return ret;
> +    } else if (par->codec_id == AV_CODEC_ID_HEVC) {
> +        if (par->extradata_size > 0 && *(uint8_t*)par->extradata != 1)
>

For the annexb format, stricter checks are as follows if follow by standard
IMO:
AV_RB24(par->extradata) == 1 || AV_RB32(par->extradata) == 1)



> +            if ((ret = ff_hevc_annexb2mp4_buf(pkt->data, &data, &size, 0,
> NULL)) < 0)
> +                return ret;
>      } else if (par->codec_id == AV_CODEC_ID_AAC && pkt->size > 2 &&
>                 (AV_RB16(pkt->data) & 0xfff0) == 0xfff0) {
>          if (!s->streams[pkt->stream_index]->nb_frames) {
> @@ -964,7 +980,12 @@ static int flv_write_packet(AVFormatContext *s,
> AVPacket *pkt)
>          avio_wb32(pb, data_size + 11);
>      } else {
>          av_assert1(flags>=0);
> -        avio_w8(pb,flags);
> +        if (par->codec_id == AV_CODEC_ID_HEVC) {
> +            avio_w8(pb, FLV_IS_EX_HEADER | PacketTypeCodedFramesX |
> frametype); // ExVideoTagHeader mode with PacketTypeCodedFramesX
>

frametype will << 2, so it's better to use below order:
FLV_IS_EX_HEADER | frametype | PacketTypeCodedFramesX



> +            avio_write(pb, "hvc1", 4);
> +        } else {
> +            avio_w8(pb, flags);
> +        }
>          if (par->codec_id == AV_CODEC_ID_VP6)
>              avio_w8(pb,0);
>          if (par->codec_id == AV_CODEC_ID_VP6F || par->codec_id ==
> AV_CODEC_ID_VP6A) {
> --
> 2.40.0
>
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