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

[David Wolstencroft]

I've found it. I'll send patch shortly. It happens when width is not mod 32.

On Sat, Dec 13, 2008 at 6:41 AM, Josef Drexler <joe-x264 at jdrexler.com>wrote:

> On Dec 13, 2008, at 2:56 PM, Guillaume POIRIER wrote:
> > On Sat, Dec 13, 2008 at 12:03 AM, Josef Drexler <joe-
> > x264 at jdrexler.com> wrote:
> >> 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/
> >
> > Thanks for the sample. I however can't reproduce the problem here
> > on Tiger.
> >
> > I used the commandline:
> > mencoder ~/Desktop/input.mkv -nosound -ovc x264 -x264encopts
> > bitrate=900:frameref=6:bframes=3:direct_pred=auto:b_pyramid:weight_b:m
> > e=umh:mixed_refs:subq=6:turbo=1:pass=2
> > -o out.avi
>
> With the unscaled 1024x576 sample, the problem doesn't happen here
> either. It does happen when scaling to PAL resolution (720x576)
> however. Please try this command line:
>
> mencoder -vf scale=::::::pal:1 -ovc x264 -x264encopts
> bitrate=900:frameref=6:bframes=3:direct_pred=auto:b_pyramid:weight_b:me=
> umh:mixed_refs:subq=6 input.mkv -o out.avi
>
> (I've removed the two-pass options I was using before since the bug
> shows up in single-pass mode too.)
>
> If that still doesn't reproduce the problem, do you have a G5 or G4?
> It might only be an issue on a 32-bit G4 CPU (or specifically, the
> 7450 that's in my Powerbook).
>
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