[FFmpeg-user] Multiple FFMpeg-Cuda-HLS-Transcoding Instances -> Deadlock Behavior

[Gabriel Balaich]

On Mon, 4 May 2020 at 02:22, Marco Kittel <marcokittel at web.de> wrote:

> Hello,
>
> i'm having a hard time rendering multiple hls instances with nvidia
> gear. The details are in the forum post. Here is a little summary.
> Everytime without any exception, when i'm running multiple instances of
> ffmpeg with cuda support, all instrances until one instance are stopping
> to work. It looks like a deadlock. Because this behavior isn't happening
> when i'm using libx264, i asked nvidia - how to fix it. I made a youtube
> video for you guys to see whats happening.
> https://www.youtube.com/watch?v=QOaf7v_Gwwk
>
> I tried every new nvidia driver and the beavior was the same. Then i
> build ffmpeg again with gcc 8, still the same behavior. I will try to
> rebuild ffmpeg with gcc 7.
>
>
> https://forums.developer.nvidia.com/t/multiple-ffmpeg-cuda-hls-transcoding-instances-deadlock-behavior/121461
>
>
> How did i build ffmpeg:
>
>
> ./configure --enable-libx264 --enable-cuvid --enable-gpl --enable-libnpp
> --enable-cuda --disable-cuda-sdk --enable-nonfree
> --extra-cflags=-I/usr/local/cuda-10.2/include
> --extra-ldflags=-L/usr/local/cuda-10.2/lib64 && make -j 8
>
>
> How i'm executing ffmpeg:
>
>
> exec $FFMPEG_PATH
> -vsync 0
> -loglevel debug
> -threads:v 1
> -threads:a 1
> -filter_threads 1
> -thread_queue_size 1024
> -hwaccel cuda
> -hwaccel_device 0
> -hwaccel_output_format cuda
> -deint adaptive
> -i “udp://$MULTICAST_ADDRESS:$PORT”
> -filter_complex
>
> “[v:0]split=4[temp1][temp2][source][temp3];[temp1]scale_npp=858:480[480p];[temp2]scale_npp=640:360[wide360p];[temp3]scale_npp=426:240[240p]”
> -g 50 -sc_threshold 0
> -map [wide360p]
> -preset medium
> -c:v:0 h264_nvenc
> -preset fast
> -profile:v baseline
> -b:v:0 600k
> -bufsize 24k
> -minrate 400k -maxrate 600k
> -map [480p]
> -c:v:1 h264_nvenc
> -preset medium
> -profile:v baseline
> -b:v:1 1000k
> -bufsize 56k
> -minrate 800k -maxrate 1600k
> -preset fast
> -map [source]
> -c:v:2 h264_nvenc
> -preset medium
> -profile:v baseline
> -preset fast
> -b:v:2 3600k
> -minrate 2000k -maxrate 4000k
> -bufsize 144k
> -map [240p]
> -c:v:3 h264_nvenc
> -preset medium
> -profile:v baseline
> -zerolatency 1
> -preset fast
> -b:v:3 400k
> -bufsize 16k
> -map a:0
> -c:a aac
> -b:a 128k
> -ac 2
> -map a:1
> -c:a aac
> -b:a 96k
> -ac 2
> -f hls
> -hls_time 4
> -hls_list_size 0
> -hls_flags append_list
> -hls_allow_cache 0
> -hls_playlist_type event
> -master_pl_name $MASTER_PLAYLIST_NAME
> -var_stream_map “a:0,agroup:audio,default:yes,language:DEU
> a:1,agroup:audio,language:FR v:0,agroup:audio v:1,agroup:audio,
> v:2,agroup:audio, v:3,agroup:audio”
> $SEGMENT_FILE_NAME
> $MEDIA_PLAYLIST_PREFIX
>
>
> Please help me to fix this behavior.
>
>
> Best regards
>
> Marco Kittel
>
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I think the issue you're running into may have to do with NVIDIA drivers
only allowing 2-3 simultaneous encodes from one video card at any given
time, unless you're using an NVIDIA Quadro in-which there is no encode
limit.

Fortunately, even on consumer cards this limit is artificially imposed and
can be bypassed with a patch:
https://github.com/keylase/nvidia-patch