[Ffmpeg-cvslog] r6231 - trunk/libavcodec/vp56.c

[Luca Barbato]

Aurelien Jacobs wrote:
> On Tue, 12 Sep 2006 09:42:26 +0200
> Luca Barbato <lu_zero at gentoo.org> wrote:
> 
>> Guillaume POIRIER wrote:
>>> Hi,
>>>
>>> On 9/12/06, aurel <subversion at mplayerhq.hu> wrote:
>>>
>>>
>>>> don't use dsp.put_pixels_tab[0][0] with unaligned ptr (fix artifacts
>>>> on altivec)
>>> Isn't there a way to make sure the arrays passed to put_pixelsXY are
>>> aligned?
>>> Even though the MMX version of put_pixel doesn't care, it would still
>>> be faster...
>>>
>>> As a side note, I imagine this has been discussed in another thread,
>>> but it's not so easy to find where because there's no link to it in
>>> the commit msg. :-P
>>>
>>> Guillaume
>> The problem is the stride that isn't 16 multiple
> 
> I don't think so.
> stride here is the linesize field from the AVFrame so I expect it to be
> 16 multiple. Note that this stride can then be negated. Could that be
> the problem ?
> 
>> put_pixel should handle unaligned load just fine.
> 
> Well, the src pointer is unaligned and we can't change this as it points
> to a random pixel in the reference frame.
> I thought that's what caused trouble with altivec isn't it ?
> 

void put_pixels16_altivec(uint8_t *block, const uint8_t *pixels, int
line_size, int h)

block must be aligned, pixel can be unaligned, line_size has to be a
multiple of 16, h can be anything.

lu

-- 

Luca Barbato

Gentoo/linux Gentoo/PPC
http://dev.gentoo.org/~lu_zero