[vlc-devel] [PATCH] Avcodec: limit the number of threads automatically selected to 12

[Rafaël Carré]

Le 2011-12-29 15:25, Sergio M. Ammirata, Ph.D. a écrit :
> Just to clarify:
> 
> I just retested on a 2 CPU machine (core i7, 6 cores each with
> multithreading enabled) which basically gives me 24 cores listed under
> /proc/cpuinfo.
> 
> When I try to transcode mpeg2 to h264, I get this error repeating over and
> over again in the debug log:
> 
> 0x80f65f0] avcodec generic warning: cannot decode one frame (36036 bytes)
> too many threads
> mpeg_decode_postinit() failure
> [0x80f65f0] avcodec generic warning: cannot decode one frame (2920 bytes)
> too many threads
> mpeg_decode_postinit() failure
> [0x80f65f0] avcodec generic warning: cannot decode one frame (6972 bytes)
> too many threads
> mpeg_decode_postinit() failure
> 
> 
> If I use --ffmpeg-threads to limit the number of threads then it works
> according to this table:
> 
> Using --ffmpeg-threads=16 or less, it works.
> Using --ffmpeg-threads=17 or more, it does not work and I get the error
> listed above.
> 
> This is consistent with J-B's statement regarding ffmpeg limit of 16
> threads.

Yeah I think the limit should be 16 if libav/ffmpeg doesn't change it
itself.

The problems with threads > number of CPU threads is something else, I
think Laurent gave a way to investigate/solve it.

You don't see it in your build (assertion failure when releasing
pictures) because you commented/worked around that problem in your
build, right?