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winlin edited this page May 23, 2022 · 2 revisions

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SRS支持HEVC编码

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SRS哪些协议支持hevc编码

支持hevc编码的协议:

FLV视频头信息

因为rtmp在2012年后,协议没有更新,对hevc编码格式的支持在rtmp协议官方文档中没有明确定义。
国内cdn厂商通过修改<video_file_format_spec_v10_1>中CodecID的定义,将flv中的hevc codecid定义为12。

Field Type Comment
Frame Type UB [4] Frame Type Type of video frame. The following values are defined:
1 = key frame (for AVC and HEVC, a seekable frame)
2 = inter frame (for AVC and HEVC, a non-seekable frame)
3 = disposable inter frame (H.263 only)
4 = generated key frame (reserved for server use only)
5 = video info/command frame
CodecID UB [4] Codec Identifier. The following values are defined:
2 = Sorenson H.263
3 = Screen video
4 = On2 VP6
5 = On2 VP6 with alpha channel
6 = Screen video version 2
7 = AVC
12=HEVC
HVCPacketType IF CodecID == 12
UI8
The following values are defined:
0 = HEVC sequence header
1 = HEVC NALU
2 = HEVC end of sequence (lower level NALU sequence ender is not required or supported
CompositionTime IF CodecID==7 OR CodecID == 12
SI24
IF AVCPacketType == 1 OR HVCPacketType == 1
Composition time offset
ELSE
0
See ISO 14496-12, 8.15.3 for an explanation of composition times. The offset in an FLV file is always in milliseconds.
VideoTagBody IF FrameType == 5
UI8
ELSE (
IF CodecID == 2
H263VIDEOPACKET
IF CodecID == 3
SCREENVIDEOPACKET
IF CodecID == 4
VP6FLVVIDEOPACKET
IF CodecID == 5
VP6FLVALPHAVIDEOPACKET
IF CodecID == 6
SCREENV2VIDEOPACKET
IF CodecID == 7
AVCVIDEOPACKET
IF CodecID == 12
HVCVIDEOPACKET
)
Video frame payload or frame info
If FrameType == 5, instead of a video payload, the Video Data Body contains a UI8 with the following meaning:
0 = Start of client-side seeking video frame sequence
1 = End of client-side seeking video frame sequence
For all but AVCVIDEOPACKET or HVCVIDEOPACKET, see the SWF File
Format Specification for details

如何rtmp推/拉流编码格式hevc

因为当前官方ffmpeg的rtmp推/拉流默认不支持hevc的编码,所以需要重新对ffmpeg进行hevc in flv的自定义修改。
需要修改3个文件即可:

  • libavformat/flv.h 新增hevc类型定义:
enum {
    FLV_CODECID_H263    = 2,
    FLV_CODECID_SCREEN  = 3,
    FLV_CODECID_VP6     = 4,
    FLV_CODECID_VP6A    = 5,
    FLV_CODECID_SCREEN2 = 6,
    FLV_CODECID_H264    = 7,
    FLV_CODECID_REALH263= 8,
    FLV_CODECID_MPEG4   = 9,
    FLV_CODECID_HEVC    = 12,
};
  • libavformat/flvdec.c
    支持hevc编码的flv解封装
  • libavformat/flvenc.c
    支持hevc编码的flv封装

如何编译支持hevc in flv的ffmpeg,请参考ffmpeg supports hevc in flv

如何rtmp推/拉流hevc示例

在完成支持hevc in flv的定制化ffmpeg编译后,rtmp推流hevc视频编码,如下:

ffmpeg -re -i source.flv -c:v libx265 -c:a copy -f flv rtmp://127.0.0.1/live/livestream

rtmp拉流hevc视频编码格式,如下:

ffmpeg -i rtmp://127.0.0.1/live/livestream -f flv -y livestream.flv

播放:

ffplay rtmp://127.0.0.1/live/livestream

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