[vlc-devel] Core i7 + FFMPEG MT bug related to invalid ES_OUT_SET_PCR calls

Laurent Aimar fenrir at elivagar.org
Wed Feb 15 12:30:16 CET 2012

On Wed, Feb 15, 2012 at 12:21:05PM +0100, Denis Charmet wrote:
> Hi,
> It looks like the  Core i7 - FFMPEG MT bug is actually a mkv bug and is
> due to an invalid use of ES_OUT_SET_PCR.
> The demux calls it for every key frame it sends to the decoder fifo.
> When I look to other demuxes they seem to send the blocks with an
> earlier timestamp than the block actually sent.
> I tried this approach with this (quick and ugly patch to test) :
> http://pastebin.com/xTeQnm5H and it seems to fix the problem. I also
> tried the avformat demux way (sending the min ts of all the tracks) but
> it seems to increase the problem (http://typx.dinauz.org/mkv.patch).
> The tests seem to agree, this is the root of the problem. Now I need a
> guru's help to really know how it should be called and if the bug is not
> elsewhere.

 It could also be that the input caching is not large enough. Try increasing it.
I think (but not checked) that the delay introduced by the decoder is not taken
into account.



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