H265: FFmpeg support HEVC over RTMP, etc.

[limjoe]

Dup to #465

[winlinvip]

This could be two questions:

1. FFmpeg requires a special version.
2. Edge may need to support H.265.

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[retamia]

FFmpeg's avformat does not support custom codec IDs like H.265 in flv. You can refer to this link for modification:
https://github.com/VCDP/CDN/blob/master/FFmpeg_patches/0001-Add-SVT-HEVC-FLV-support-on-FFmpeg.patch

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[crazymxm]

The problem is, even if it is resolved, can the server handle the load when using ffmpeg (CPU situation) to convert 10 streams simultaneously (h265->h264)?

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[runner365]

It seems like your problem is about ffmpeg wanting to include flv support for h265. Refer to this link to compile ffmpeg4.1 by yourself: https://github.com/runner365/ffmpeg_rtmp_h265

The fearue/h265 branch of SRS supports h265 in flv. Are there any issues with h265 in the SRS streaming media server?

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[limjoe]

@runner365 The srs feature/h265 can successfully receive H.265 streams and also distribute FLV and RTMP H.265 streams without any issues.

Currently, I want to configure the transcode feature to convert the incoming H.265 stream into an additional H.264 stream. When compiling the srs feature/h265 branch, I added the --ffmpeg-tool=on parameter. However, the compiled objs/ffmpeg/bin/ffmpeg does not support H.265. So, I manually compiled a version of FFmpeg from Kingsoft Cloud and plan to use this compiled FFmpeg for transcoding in transcode.

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[limjoe]

@limjoe The problem is, even if it is resolved, can the server handle the load of converting 10 streams simultaneously with ffmpeg (CPU situation) (h265->h264) on the server side?

My internet monitoring scenario involves a large number of streams being pushed, but very few streams being pulled or hardly anyone watching them normally.

@crazymxm What I have in mind is to use the originCluster mode, where transcoding at the Edge side will only be done on-demand when someone is watching the stream (i.e., transcoding will only be done when there are viewers). We just need to add machines on the server side, and we will use GPUs or dedicated NETINT transcoding cards for the transcoding process.

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[limjoe]

H265 transcoding consumes a lot of CPU resources. Adjusting ffmpeg parameters can reduce the latency of transcoded streaming playback.

transcode live {
        enabled     on;
        ffmpeg      /usr/local/srs/objs/FFmpeg/ffmpeg;
        engine h265{
            enabled     on;
            iformat     flv;
            vcodec          libx264;
            vthreads        2;
            vprofile        baseline;
            vpreset         veryfast;
            acodec          copy;
            oformat         flv;
            output          rtmp://127.0.0.1:[port]/[app]?vhost=[vhost]/[stream]_[engine];
        }
    }

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