CODEWITHSUNDEEP
nginxvideoffmpegyoutubertmp
Mike Miller
Mike Miller

Reputation: 3129

Use FFMPEG to restream RTMP source to YouTube - no video stream in output

I am attempting to grab the .m3u8 file from an nginx-rtmp server and pass it along to YouTube rtmp. I believe this to be possible (for example here: https://stackoverflow.com/a/11978820/1552594 although this is on the same host). The command I am using is:

ffmpeg -analyzeduration 0 -i \
http://source.rtmp.server/hls/stream.m3u8 -pix_fmt yuv420p \ 
-f flv rtmp://a.rtmp.youtube.com/live2/xxxx-xxxx-xxxx-xxxx

However the output contains only audio and YouTube doesn't like it. The command produces following:

NOOO VIDEOOOO

As you can see no Video stream in output metadata, stream mapping shows only audio and the trace shows 0kb of Video for 651kb of Audio

Any help much appreciated

MORE INFO

Improved version of the command lifted from this article:

https://judge2020.com/restreaming-a-m3u8-hls-stream-to-youtube-using-ffmpeg/

"Restreaming a m3u8 HLS stream to Youtube using FFMPEG" AKA exactly what I am trying to do.

The command I am sending is now:

ffmpeg -re -i "http://source.rtmp.server/hls/stream.m3u8" \ 
-strict -2 -c:v copy -c:a aac -ar 44100 -ab 128k -ac 2 -flags \ 
+global_header -bsf:a aac_adtstoasc -bufsize 3000k -f flv \ 
"rtmp://a.rtmp.youtube.com/live2/xxx-xxxx-xxxx-xxxx"

I got pretty much exactly the same response except with the Audio being read and output using aac codec.

enter image description here

MORE MORE INFO

I have found that adding a mapping can force the video stream into the output:

ffmpeg -re -i "http://source.rtmp.server/hls/stream.m3u8" \
-strict -2 -c:v copy -c:a -map 0:0 -map 0:1 -ar 44100 -ab 128k -ac 2 \ 
-flags +global_header -bsf:a aac_adtstoasc -bufsize 1000k \
-f flv "rtmp://a.rtmp.youtube.com/live2/xxxx-xxxx-xxxx-xxxx"

This throws up the error that has presumably been resulting in the video stream being silently dropped:

enter image description here

Upvotes: 2

Views: 8425

Answers (1)

Mike Miller
Mike Miller

Reputation: 3129

Finally worked it out. The last issue above was a red herring and was due to missing a codec argument for the audio -c:a.

The complete working command is as follows:

ffmpeg -probesize 100M -analyzeduration 20M -re \ 
-i "http://source.rtmp.server/hls/stream.m3u8" -strict -2 -c:v \ 
libx264 -pix_fmt yuv420p -c:a aac -map 0:0 -map 0:1 -ar 44100 \ 
-ab 128k -ac 2 -b:v 2567k -flags +global_header -bsf:a aac_adtstoasc \ 
-bufsize 1000k -f flv "rtmp://a.rtmp.youtube.com/live2/xxxx-xxxx-xxxx-xxxx"

The important parts are -probesize and -analyeduration - these need tweaking until they work. The -re flag is important to indicate restreaming. The various video codec declarations are also important - -c:v libx264 -pix_fmt yuv420p or it will throw errors about the output size being 0x0. Finally the map flags ensure that both streams are included in the output: -map 0:0 -map 0:1

Upvotes: 7

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