[FFmpeg-user] RTMP WriteN error using NVENC while libx264 works fine

[Roger Pack]

Does your RTMP server show any logs?

On 12/9/15, Matthew Shapiro <me at mshapiro.net> wrote:
> I am trying to run some transcoding tests to figure out how well ffmpeg
> works on some GPU servers we have.
>
> From my desktop I am sending up an RTMP stream via OBS to a media server
> system we have running.  I then started ffmpeg with arguments to pull that
> feed from the media server and push it back to a different ingestion point
> on that server.  So for example with libx264 I am invoking it with the
> following:
>
> ffmpeg -loglevel verbose -i "rtmp://server/live/matt-input live=1" -vcodec
> libx264 -ar 44100 -f flv "rtmp://server/live/matt-test1"
>
> This is meant as a bare bones basic test without doing any meaningful
> conversion, and it works perfectly.  I"m able to subscribe to
> rtmp://server/live/matt-test1 and see my vide out.
>
> However, when I change libx264 to nvec:
>
> ffmpeg -loglevel verbose -i "rtmp://server/live/matt-input live=1" -vcodec
> nvenc -ar 44100 -f flv "rtmp://server/live/matt-test1"
>
> After about 70-90 frames it gives me WriteN, RTMP send error 104 (136
> bytes).  The metadata that ffmpeg sees from this video is:
>
> Metadata:
>   Server                NGINX RTMP (github.com/arut/nginx-rtmp-module)
>   width                 1920.00
>   height                1080.00
>   displayWidth          1920.00
>   displayHeight         1080.00
>   duration              0.00
>   framerate             30.00
>   fps                   30.00
>   videodatarate         0.00
>   videocodecid          0.00
>   audiodatarate         0.00
>   audiocodecid          0.00
>   profile
>   level
> Input #0, live_flv, from 'rtmp://server/live/matt-input live=1':
>   Metadata:
>     Server          : NGINX RTMP (github.com/arut/nginx-rtmp-module)
>     displayWidth    : 1920
>     displayHeight   : 1080
>     fps             : 30
>     profile         :
>     level           :
>   Duration: 00:00:00.00, start: 4.736000, bitrate: N/A
>     Stream #0:0: Video: h264 (High), 3 reference frames, yuv420p(tv,
> bt709/bt709/iec61966-2-1), 1920x1080 (1920x1088) [SAR 1:1 DAR 16:9], 30.30
> fps, 30 tbr, 1k tbn, 60 tbc
>     Stream #0:1: Audio: aac (LC), 48000 Hz, stereo, fltp
>
>
> It appears that NVENC has some incompatibility when it comes to rtmp that
> libx264 does not have.  It's also interesting to note that if I use ffmpeg
> to encode the big buck bunny video and send it up to
> rtmp://server/live/matt-input, then I am able to successfully use NVENC to
> pull down the video and push it back up no problem.  For reference, the BBB
> video is seen by FFMPEG as:
>
> Metadata:
>   Server                NGINX RTMP (github.com/arut/nginx-rtmp-module)
>   width                 1920.00
>   height                1080.00
>   displayWidth          1920.00
>   displayHeight         1080.00
>   duration              0.00
>   framerate             60.00
>   fps                   60.00
>   videodatarate         0.00
>   videocodecid          7.00
>   audiodatarate         125.00
>   audiocodecid          1.00
>   profile
>   level
> Input #0, live_flv, from 'rtmp://server/live/matt-input live=1':
>   Metadata:
>     Server          : NGINX RTMP (github.com/arut/nginx-rtmp-module)
>     displayWidth    : 1920
>     displayHeight   : 1080
>     fps             : 60
>     profile         :
>     level           :
>   Duration: 00:00:00.00, start: 1.950000, bitrate: N/A
>     Stream #0:0: Video: h264 (High), yuv420p(tv), 1920x1080 [SAR 1:1 DAR
> 16:9], 62.50 fps, 60 tbr, 1k tbn, 120 tbc
>     Stream #0:1: Audio: adpcm_swf, 44100 Hz, stereo, s16, 352 kb/s
>
> Also, if needed I compiled FFMPEG using the instructions from
> http://developer.download.nvidia.com/compute/redist/ffmpeg/1511-patch/FFMPEG-with-NVIDIA-Acceleration-on-Ubuntu_UG_v01.pdf,
> and the beginning of the ffmpeg output looks like:
>
> # ffmpeg -i "rtmp://server/live/matt-input live=1" -vcodec nvenc -ar 44100
> -f flv "rtmp://server/live/matt-test1"
> ffmpeg version N-76538-gb83c849 Copyright (c) 2000-2015 the FFmpeg
> developers
>   built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04)
>   configuration: --enable-nonfree --enable-nvenc --enable-nvresize
> --extra-cflags=-I../cudautils --extra-ldflags=-L../cudautils --enable-gpl
> --enable-libx264 --enable-librtmp
>   libavutil      55.  5.100 / 55.  5.100
>   libavcodec     57. 15.100 / 57. 15.100
>   libavformat    57. 14.100 / 57. 14.100
>   libavdevice    57.  0.100 / 57.  0.100
>   libavfilter     6. 15.100 /  6. 15.100
>   libswscale      4.  0.100 /  4.  0.100
>   libswresample   2.  0.101 /  2.  0.101
>   libpostproc    54.  0.100 / 54.  0.100
>
>
> I have tried changing my OBS settings one at a time (both multi-platform
> and non-multiplatform versions) to no avail.  Pulling from other streams
> seems to cause the same thing to happen, and the only stream I've been able
> to pull, transcode, then re-push via RTMP (via NVENC) seems to be one that
> originates straight from FFMPEG
>
> Does anyone have any suggestions on what might be wrong?  Is there
> something on my end that is causing rtmp to fail or is it a bug in the
> NVENC encoder?
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