[FFmpeg-devel] [PATCH] snow: remove strange av_assert2

Michael Niedermayer michaelni at gmx.at
Fri Jul 10 02:12:50 CEST 2015


On Thu, Jul 09, 2015 at 08:24:52PM +0200, Andreas Cadhalpun wrote:
> On 08.07.2015 18:07, Michael Niedermayer wrote:
> > On Wed, Jul 08, 2015 at 07:24:13AM -0400, Ronald S. Bultje wrote:
> >> - last of all, I want to remind you guys that we haven't done a very
> >> thorough code analysis to see if this can actually be triggered. As an
> >> example, look at commit 458446acfa1441d283dacf9e6e545beb083b8bb0. Before
> >> that, vp8 files smaller than 16x16 or vp9 files smaller than 64x64 could
> >> cause aborts. The vp9 ones I noticed due to some fate files being so small.
> >> I doubt you'll ever find such vp8 files, but they're valid.
> >>
> >> Let's not add silly checks to replace other silly ones.
> 
> Do you have any vp9 files triggering this assert?
> 
> > if people prefer i ca revert b8c438e7623644edcfdb508c946a723a3b79b893
> > or add a check for stride == 0
> > 
> > what do people prefer ?
> 
> The assert can be triggered by the h264 decoder:
> mc_dir_part in libavcodec/h264_mb.c calls the 16 bit variant of
> emulated_edge_mc and thus the assert is triggered due to the
> sizeof(pixel) factor, even though block_w is smaller than buf_linesize.
> 
> If that's valid behavior of the h264 decoder, then the assert should
> be removed, but if on the other hand this is a bug in the h264
> decoder, then that should be fixed and the assert remain.

just posted a patch which should fix these assertion failures

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I do not agree with what you have to say, but I'll defend to the death your
right to say it. -- Voltaire
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