[FFmpeg-devel] [PATCH] pthread: Fix ff_thread_get_formatissues when called outside frame decode.

[Reimar Döffinger]

On 09.03.2015, at 07:38, Rainer Hochecker <fernetmenta at online.de> wrote:
> Reimar Döffinger <Reimar.Doeffinger <at> gmx.de> writes:
> 
>> 
>> Any reason to believe this patch causes it?
>> Because I can't see how it would.
>> Maybe it's just a bug with DXVA and multithreading in the HEVC code?
>> Can you provide some more information like a stacktrace, possibly using a
> tool like DrMemory?
> 
> I don't think the patch itself is the root cause of the issue, it just
> triggers it. get_format is called 4 times, something seems to get corrupted
> in opening our hw decoder.
> Do you have an explanation why it works with thread_safe_callbacks set to 1?

As you get green frames it does not really "work". It might simply be that setting it breaks decoding of the first frames and thus the code causing the issues is never executed.

> I am wondering if hevc misses the multithreading fix done for other codecs:
> http://ffmpeg.org/pipermail/ffmpeg-cvslog/2013-March/062620.html
> 
> What do you think?

Mostly I think that I don't have enough information by far, someone will have to do proper debugging. And as long as this is a Windows-only issue very few people will be able to help.
But the fact that my previous patch worked for me despite the major bug suggests that HEVC does not call the can_start function properly.