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

[David Wolstencroft]

OK, patch attached.
I've incorrectly assumed that i_src_stride in mc_chroma functions will
always be mod 16.

- David

On Sat, Dec 13, 2008 at 9:07 AM, David Wolstencroft <lordrpi at gmail.com>wrote:

> 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).
>>
>> _______________________________________________
>> x264-devel mailing list
>> x264-devel at videolan.org
>> http://mailman.videolan.org/listinfo/x264-devel
>>
>
>
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