[FFmpeg-devel] [RFC] Request for pixdesc API review

[Michael Niedermayer]

On Wed, Nov 18, 2009 at 08:35:24PM +0100, Stefano Sabatini wrote:
> On date Wednesday 2009-11-18 18:14:30 +0100, Michael Niedermayer encoded:
> > On Wed, Nov 18, 2009 at 12:47:00AM +0100, Stefano Sabatini wrote:
> > > On date Tuesday 2009-11-17 16:24:16 +0100, Stefano Sabatini encoded:
> [...]
> > > > Alternatively we could have a bit in the component telling if the
> > > > component is a chroma component, what about it?
> > > 
> > > I thought a little more about this other option, I have a slight
> > > preference for it since it provides more expressivity to the pixdesc,
> > > allowing to say for example if a pixel format contains chroma
> > > components.
> > > 
> > > Also it *slightly* simplifies expressions of the kind:
> > >    s = (i == 1 || i == 2) ? expr(log2_chroma) : 0;
> > > 
> > > which become:
> > >    s = pixdesc->comp[i]->is_chroma ? expr(log2_chroma) ? 0;
> > 
> > thats not a simplification thats hugely worse code, the compiler
> > can unroll and optimize away the first but not the second
> > also it wastes the last spare bit in 16bits
> 
> So another attempt at clarifying docs.
> 
> Regards.
> -- 
> FFmpeg = Furious Fundamental Mere Portable Enigmatic Ghost

>  pixdesc.h |   10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 02afdc28486127adab09ff324f159f3f649b54e5  clarify-docs-for-chroma-comp.patch

ok

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

I wish the Xiph folks would stop pretending they've got something they
do not.  Somehow I fear this will remain a wish. -- M?ns Rullg?rd
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