[x264-devel] Bug: horizontal stripes on PPC with Altivec since snapshot 20081125

[Josef Drexler]

On Dec 12, 2008, at 8:46 PM, David Wolstencroft wrote:
> Josef,
>
> I'll try this out when I get home today.
>
> Can you give me some more information, such as source dimensions of  
> the video?

The source is 1024x576 h.264 video which I'm transcoding to 720x576  
with SAR=64/45 (16:9 at PAL resolution). I believe mencoder would do  
the scaling, so the input to x264 is 720x576.

I've now tried another sample, for which the problem doesn't appear  
only as stripes but rather generally discolored areas too. In case it  
helps for reproducing the problem, I've uploaded a small sample  
together with the resulting good and broken encodes at http:// 
jdrexler.com/home/x264-ppc-regression/

> - David
>
> On Fri, Dec 12, 2008 at 11:41 AM, Jason Garrett-Glaser  
> <darkshikari at gmail.com> wrote:
> On Fri, Dec 12, 2008 at 9:01 AM, Josef Drexler <joe- 
> x264 at jdrexler.com> wrote:
> > Since the version in snapshot x264-snapshot-20081125-2245.tar.bz2,
> > x264 encodes show semi-random, clearly visible horizontal stripes of
> > what looks like excessive color saturation, particularly in dark
> > areas surrounded by light areas. Versions up to and including x264-
> > snapshot-20081124-2245.tar.bz2 do not exhibit this problem.
>
> Sounds like http://git.videolan.org/? 
> p=x264.git;a=commit;h=4bf4109aee5b602f8a124b434e18f93ef539bbe6
> broke some things he wasn't intending...
>
> Well, good thing I don't maintain Altivec, so I can just yell at the
> people who do.
>
> Dark Shikari

-- 
Josef Drexler
josef at ttdpatch.net

-- 
Josef Drexler
josef at ttdpatch.net