Optimization idea: soft XvPutImage

Roland Scheidegger sroland at tungstengraphics.com
Wed Sep 17 06:44:51 PDT 2008

On 17.09.2008 14:22, Adam Richter wrote:
> 	2) Many open source drivers lack this YUV/stretch capability
> 	   even if the hardware has it, due to lack of public
> 	   documentation or slow development in comparison to the
> 	   life cycle of the hardware, even though efforts to address
> 	   these problems are definitely helping.
Note that for this case, you could just implement this in the driver
itself (might be easiest for figuring out if it really helps in practice).

> 	The memory bus utilization would also be reduced (but never
> more than that factor 3) as the ratio of the size of the unstretched
> video to stretched video increases, such as when playing a 720x480 video
> on a newer 2560x1600 display.
It works the other way around too however, think Full HD playback on a
(mobile) device with a (say) 800x480 screen (not that I'd say this is
very common, but it's a case which could definitely happen). Of course,
"normal" Xv needs to transfer the full resolution image too (albeit only
as packed or more common planar yuv which is a bit smaller).

I could see this being faster and provide some benefits, but I don't
know if it's worth the effort.


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