Re: YUV support

["Antonino A. Daplas" <adaplas@gmail.com>]

Dennis Munsie wrote:
> Hi again,
> 
> I'm starting to investigate adding YUV support to the intelfb driver,  
> and I was wondering what support is already in the framebuffer  
> subsystem for YUV.  Doing a quick grep for YUV only yielded a handful  
> of references -- all in drivers.  Nothing seems to be there for  
> generic YUV support.
> 
> Am I correct in this assumption?

Yes, you are correct.

> And, if so, what would be the best  
> way to expose YUV support?

Create a new visual, FB_VISUAL_YUV_PACKED, then treat 
var->{red,green,blue} as Y, U and V instead. This way, one can continue
to use the cfb_* generic drawing funtions.

For planar formats, it's pretty much the same except you have to provide
your own drawing functions.

> Driver specific ioctl's?

sysfs is probably better.

> Separate fb  
> device for the YUV overlay?

Yes. Some drivers have fb0 for the primary, fb1 for the overlay, and fb2 for
the cursor.

>  Give up and use X?

Or you can use directfb, I bet the i830 there has overlay support.

Tony

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