On Thu, 17 Feb 2005 00:09:59 +0100, Attila Kinali <[EMAIL PROTECTED]> wrote:
> On Thu, 17 Feb 2005 01:17:47 +0800
> "HiNet" <[EMAIL PROTECTED]> wrote:
> 
> >     Just as Nicolai said, everything can be done with 3D hardware
> > function of graphics cards. And if I am correct, only ATI's graphic
> > chips can support both 3D and colorkey in the same time. Hence,
> > we can do some OSD by using the feature of colorkey if we use
> > ATI's card. However, ATI does not support 16 bit color mode in
> > their close source driver for linux. Besides, some uncompressed
> > video streams are in YUV space.
> 
> Actualy, YUV is the most used colorspace for video applications.
> One reason is because it decorelates the three colour planes
> quite efficiently and the other is that you can use
> supsampling because of this decorelation.
> In the extreme case with 4:2:0 you effectively half
> the amount of raw data per frame.
> That's why a converter is a must have, but i don't think
> that's too difficult, it's iirc 9 multipliers with
> constant multipicants and 6 adders. Shoudln't need too
> many gates.

It's not even that bad.  Some of the multiplies are trivial.  Like
multiplying by 129 is just an adder.
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