[Mesa-dev] [Intel-gfx] [PATCH] dri3, i915, i965: Add __DRI_IMAGE_FOURCC_SARGB8888

[Ville Syrjälä]

On Fri, Nov 22, 2013 at 03:43:13PM -0800, Keith Packard wrote:
> Ville Syrjälä <ville.syrjala at linux.intel.com> writes:
> 
> > What is this format anyway? -ENODOCS
> 
> Same as MESA_FORMAT_SARGB8 and __DRI_IMAGE_FORMAT_SARGB8 :-)
> 
> > If its just an srgb version of ARGB8888, then I wouldn't really want it
> > in drm_fourcc.h. I expect colorspacy stuff will be handled by various
> > crtc/plane properties in the kernel so we don't need to encode that
> > stuff into the fb format.
> 
> It's not any different from splitting YUV codes from RGB codes;

Not really. Saying something is YUV (or rather Y'CbCr) doesn't
actually tell you the color space. It just tells you whether the
information is encoded as R+G+B or Y+Cb+Cr. How you convert between
them is another matter. You need to know the gamma, color primaries,
chroma siting for sub-sampled YCbCr formats, etc.

-- 
Ville Syrjälä
Intel OTC