Xvideo performance on Radeon 7500 vs Intel 915

Roland Scheidegger sroland at tungstengraphics.com
Sun Dec 3 11:38:36 PST 2006

Linxiao wrote:
> Hi, Roland:
>      NV's Xv also just converts planar yuv (YV12) to packed yuv (VYUY) 
> for display.
> ( I have had a glimpse of nv_video.c in Xorg6.8.2/7.1.) And that 
> consumes CPU a lot,
> especially when I use nv's blitter ports to play 16channels X CIF YV12 
> video stream
> which each is created as an XvImage and played with XvShmPutImage.
>     Is there any existing patch for this? (I use nv 9550, and it should 
> support planar
> yuv hardwarely.) If no, would you please provide any suggestion on 
> playing multiple
> channels of video?
what is nv 9550? Such a chip does not exist.
Anyway, the nv driver handles video vastly different than what the 
radeon driver currently does. Instead of using a back-end scaler which 
is used directly at scan-out, it does a scaled, filtered blit (that's 
pretty close what a normal texturing operation does). I'm not convinced 
the blitter really could handle planar yuv directly, maybe you'd need 
something like a fragment shader to compose the final image back out of 
the three planes. The nouveau project might have some ideas how you 
could do that, or at least may in the future.


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