[Open-graphics] RGB/YUV converstion... importance?

[Attila Kinali]

On Sat, 09 Sep 2006 09:18:34 +0200
Raphael Jacquot <raphael.jacquot at imag.fr> wrote:

> Attila Kinali wrote:
> 
> > The most common used subsampling format is 4:2:0 where there is
> > one U/V sample per 4 Y sample. Ie one U/V sample per every second
> > pixel and every second line. 
> 
> and having 4:2:2 will get you professionnal users

If you can do 4:2:0, then 4:2:2 is easy. Just leave one
part of the functionality out (ie, the skipping of every
second line for U/V)
 
> > And i wouldn't impose that onto the CPU. The Matrox G200 used
> > and interleaved YUV format, which mean that the player software
> > had to first convert the planar data into a interleaved format
> > and then showel it over to the card. In the case of MPlayer this
> > made a 10-20% performance los for the whole player (comparing
> > the G200 to the G400), which means that for the transfere the
> > los must have been somewhere between 50% and 80%.
> 
> imho, the thing should accept both planar and interleaved
> professionnal systems use interleaved, as they work from streams

No, G200 could only do interleaved, G400 and later can do both.
(At least as i remember the specs, haven't read them in ages)

Anyways, for performance reasons (in video applications)
it's important that we can handle planar data in hardware.

			Attila Kinali
-- 
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