[FFmpeg-devel] [PATCH] swscale: Fix NV12/NV21 support

[Michael Niedermayer]

On Thu, May 21, 2009 at 06:22:16PM +0300, Ville Syrj?l? wrote:
> On Thu, May 21, 2009 at 04:38:53PM +0200, Michael Niedermayer wrote:
> > On Thu, May 21, 2009 at 04:01:58PM +0300, Ville Syrj?l? wrote:
> > > On Thu, May 21, 2009 at 05:30:19AM +0200, Michael Niedermayer wrote:
> > > > On Wed, May 20, 2009 at 10:03:05PM +0300, Ville Syrj?l? wrote:
> > > > > Hi,
> > > > > 
> > > > > NV12/NV21 support is currently broken due to the introduction of
> > > > > planarCopy. The logic for selecting planarCopy assumes that all
> > > > > planar YUV formats with the same subsampling factors are compatible.
> > > > > That is not the case for NV12/NV21. The simple solution is to
> > > > > never use planarCopy for NV12/NV21.
> > > > 
> > > > patch probably ok
> > > > i assume this fixes some values from swscale-example?
> > > 
> > > Didn't know about that one. I just noticed the problem with mplayer when
> > > trying to use nv12 as the vo format. The output was b/w, after the patch
> > > the colors are back.
> > > 
> > > I just tried swscale-example and can't see any difference in the output
> > > w/ or w/o the patch. Oh, I see that swscale-example will never test
> > > nv12/nv21 because they are not supported as input formats. So even in
> > > the nv12 -> nv12 case where planarCopy might work the last step to
> > > convert back to yuv420p will always fail.
> > 
> > maybe you want to add nv* input support :) ?
> 
> Seems like mostly wasted effort. I doubt any application would ever use
> that code so the only benefit would be getting swscale-example working.

Thats one way to see it agreed but theres also that without input support
it cant be tested (like with swscale-example) and we wouldnt be discussing
this bugfix in this thread if there was functioning testing for NV*
so it does not really appear that useless to me, lack of it already caused
a bug to be missed

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
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