GL_422_EXT

Does anybody have some sample code using the GL_422_EXT extension in praxis availabe ? I need it for fast YUY2 data expansion.
I studied all availabe documentation to this extension, but practical testing on Wildcat 6110 shows that I am not able to catch something …
Does anybody know what is the diference of this GL_422_EXT in comparison to GL_FORMAT_SUBSAMPLE_24_24_OML ?

Here is how we used to do YUV packed pixel
drawing on the SGI O2. Unfortunately I
dont think it ever caught on.

glDrawPixels(pwid, phei, GL_YCRCB_422_SGIX,
GL_UNSIGNED_BYTE, yourbufferhere);

Has YUV Unpacking ever been covered in an
ATI or Nvidia extension?

The GL_422_EXT group of extension is supported ony on Wildcat II,III,IV nad on Filre GL 3,4 …
I have catched how it works now. It is realy very useful for fast video processing …
I is a pitt that nVida does not have an equivalent + faster color matrix implemnetation …