On Mon, Mar 9, 2015 at 1:50 PM, Reimar Döffinger <reimar.doeffin...@gmx.de> wrote: > On 9 March 2015 13:34:24 CET, Hendrik Leppkes <h.lepp...@gmail.com> wrote: >>On Mon, Mar 9, 2015 at 7:38 AM, Rainer Hochecker >><fernetme...@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? >>> >>> 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? >>> >> >>I build the HEVC HWAccel support, and I consider frame-threading with >>hwaccel an abomination that should not be supported, so I didn't spend >>any time thinking about it. >> >>Honestly, there are several issues with MT+HWaccel in H264 as well, at >>least on Intel hardware, so I can only strongly urge everyone to not >>combine it. There is zero advantages, and only downsides! > > Only if you completely ignore the practical issues that anyone trying to use > it will have. > In many cases applications will not know whether hardware supports decoding > the video until there get_format call. Worse, it can even change from > supported to not supported. > Do you expect everyone to disable multithreading "just in case"? Buffer the > last n bits of data to be able to restart decoding?
What I do is simply restart decoding with the packet that failed the hardware decoder. Don't need to buffer anything, you still have the AVPacket in question anyway. This allows a perfect and seamless change without requiring the hwaccel-mt hack. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel