[FFmpeg-user] RTMP to RTMP transcoding - error while copying the video track

[Arnaud A]

Hi all,

I have the following error:

|[flv @ 0x41b4680] pts (-4080) < dts (67) in stream 0
av_interleaved_write_frame(): Invalid argument|


Here is my command line:

|./ffmpeg -i rtmp://myserver/live/test -c:v copy -c:a libvo_aacenc -b:a 96k -f flv rtmp://myserver/live-flash/test|

Context:
I need to fecth a RTMP H.264/MP3 stream and push it to RTMP H264/AAC 
stream. I would like to leave the video track untouched as I have 
several streams to process and would like CPU usage to remain as low as 
possible.
Now one out of 10 tries it passes and the stream gets transcoded but 
most of time I have the above error. The incoming stream is not 
transcoded to H264 with x264 (it is with Flash Media Live Encoder) but 
if I specify -c:v libx264 (+x264 options) instead of -c:v copy it works 
100% of the time. Any hints on what is happening?

Console output:

|ffmpeg version 2.2.1-   http://johnvansickle.com/ffmpeg/    Copyright (c) 2000-2014 the FFmpeg developers
built on Apr 11 2014 04:58:33 with gcc 4.8 (Debian 4.8.2-19)
configuration: --enable-gpl --enable-version3 --disable-shared --disable-debug --enable-runtime-cpudetect --enable-libmp3lame --enable-libx264 --enable-libwebp --enable-libspeex --enable-libvorbis --enable-libvpx --enable-libfreetype --enable-fontconfig --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-gray --enable-libopenjpeg --enable-libopus --disable-ffserver
libavutil      52. 66.100 / 52. 66.100
libavcodec     55. 52.102 / 55. 52.102
libavformat    55. 33.100 / 55. 33.100
libavdevice    55. 10.100 / 55. 10.100
libavfilter     4.  2.100 /  4.  2.100
libswscale      2.  5.102 /  2.  5.102
libswresample   0. 18.100 /  0. 18.100
libpostproc    52.  3.100 / 52.  3.100
[flv @ 0x401d520] Stream discovered after head already parsed
[flv @ 0x401d520] negative cts, previous timestamps might be wrong
Last message repeated 61 times
Input #0, flv, from 'rtmp://87.106.183.100/live/test':
Metadata:
author          :
copyright       :
description     :
keywords        :
rating          :
title           :
presetname      : Custom
creationdate    : Tue Apr 29 14:17:16 2014
                 :
videodevice     : Logitech HD Webcam C525
avclevel        : 40
avcprofile      : 77
videokeyframe_frequency: 5
audiodevice     : Microphone (Jabra UC VOICE 550a)
audiochannels   : 2
audioinputvolume: 75
Duration: N/A, start: 0.000000, bitrate: 847 kb/s
Stream #0:0: Video: h264 (Main), yuv420p(tv), 640x360 [SAR 1:1 DAR 16:9], 716 kb/s, 15.17 fps, 48.17 tbr, 1k tbn, 30 tbc
Stream #0:1: Audio: mp3, 44100 Hz, stereo, s16p, 131 kb/s
Stream #0:2: Data: none
Output #0, flv, to 'rtmp://87.106.183.100/live-flash/test':
Metadata:
author          :
copyright       :
description     :
keywords        :
rating          :
title           :
presetname      : Custom
creationdate    : Tue Apr 29 14:17:16 2014
                 :
videodevice     : Logitech HD Webcam C525
avclevel        : 40
avcprofile      : 77
videokeyframe_frequency: 5
audiodevice     : Microphone (Jabra UC VOICE 550a)
audiochannels   : 2
audioinputvolume: 75
encoder         : Lavf55.33.100
Stream #0:0: Video: h264 ([7][0][0][0] / 0x0007), yuv420p, 640x360 [SAR 1:1 DAR 16:9], q=2-31, 716 kb/s, 15.17 fps, 1k tbn, 1k tbc
Stream #0:1: Audio: aac (libvo_aacenc) ([10][0][0][0] / 0x000A), 44100 Hz, stereo, s16, 96 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (mp3 -> libvo_aacenc)
Press [q] to stop, [?] for help
[flv @ 0x41b4680] pts (-4080) < dts (67) in stream 0
av_interleaved_write_frame(): Invalid argument
[libvo_aacenc @ 0x41b5640] Trying to remove 1024 samples, but the queue is empty
[flv @ 0x41b4680] Encoder did not produce proper pts, making some up.
[libvo_aacenc @ 0x41b5640] Trying to remove 1024 samples, but the queue is empty
[flv @ 0x41b4680] Failed to update header with correct duration.
[flv @ 0x41b4680] Failed to update header with correct filesize.
frame=    2 fps=0.0 q=-1.0 Lsize=      30kB time=00:00:00.04 bitrate=5383.3kbits/s
video:36kB audio:1kB subtitle:0 data:0 global headers:0kB muxing overhead -16.655897%|

Thanks