[FFmpeg-devel] [PATCH] Fix threaded mpeg*video encoding

Måns Rullgård mans
Thu Jul 1 13:26:25 CEST 2010

Michael Niedermayer <michaelni at gmx.at> writes:

> On Thu, Jul 01, 2010 at 04:01:24AM +0100, M?ns Rullg?rd wrote:
>> Michael Niedermayer <michaelni at gmx.at> writes:
>> > On Wed, Jun 30, 2010 at 03:49:34PM +0100, Mans Rullgard wrote:
>> >> This allocates per-thread copies of some buffers which are updated
>> >> concurrently from the encoding threads.
>> >
>> > is this fixing a bug?
>> > if so please elaborate what and where. My guess would be toward
>> > ac_val being the one causing the issues.
>> The threaded regression tests are failing randomly with pthreads enabled:
>> http://fate.multimedia.cx/index.php?test_result=66882641
>> http://fate.multimedia.cx/index.php?test_result=66852547
>> http://fate.multimedia.cx/index.php?test_result=66876769
>> Those are just a few examples.  Valgrind complained about most of
>> those buffers, particularly ac_val and dc_val, and I add a couple
>> since they were written close to the places valgrind identified.  Race
>> detection is never exact.
> could you try to just change ac_val and see if this makes the issue
> go away?
> for ac_val i found ff_mpeg4_clean_buffers() as possible reason for the
> race, for the others i am not aware of code that can lead to a race

So OK to commit just the ac_val parts and see what happens?

M?ns Rullg?rd
mans at mansr.com

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