[FFmpeg-user] Encoding x264 hangs in a high turn over pipeline

Nicolas George nicolas.george at normalesup.org
Wed Jul 25 13:43:18 CEST 2012

L'octidi 8 thermidor, an CCXX, Luke a écrit :
> We are testing ffmpeg in our compression pipeline as our commercial
> software does not provide the functionality we need.
> We run a multithreaded compression (ffmpeg multithreading isn't
> used, our own solution is) using the following command:
> ffmpeg -i #input# -f mp4 -vcodec libx264 -s 1024x576 -b:v 2000k -g
> 33 -acodec libmp3lame -b:a 128k -ar 44100 -vf "movie=#logo# [wm];
> [in][wm] overlay=10:main_h-overlay_h-10 [out]" -y #output#
> Approx. 75% threads complete without any problems, the remaining
> ones get stuck - cpu usage on each thread drops to 0, memory usage
> gets stuck at around 300MB.

Can you reproduce the problem with another video codec, such as the internal
MPEG4 encoder, or maybe even with -f null?

Can you try to find out where ffmpeg is stuck? A way to do that would be to
run the debug version (ffmpeg_g), and when it is stuck, attach it with gdb
(gdb ffmpeg_g $(pidof ffmpeg_g)), get a backtrace and then detach it: a few
iterations of that would show where ffmpeg spends most of its time.

> Initially we used aac and libvo_aacenc coders for audio, but the
> hangs seemed more frequent.

You will probably get more quality out of lame anyway.


  Nicolas George
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