XVideo question?

[Alex Deucher]

On Tue, 23 Nov 2004 09:47:02 -0800, Kendall Bennett
<kendallb at scitechsoft.com> wrote:
> Hi Guys,
> 
> I am working on our XVideo implementation and am wondering what the
> offscreen video memory functions are used for. More specifically what
> applications make use of these calls and what client level API is used to
> call them.
> 
> So far with my testing of MPlayer and Xine, it appears that only end up
> going into the drivers PutImage function, and don't seem to use the
> offscreen video memory functions. This means that all video frames get
> dumped to system memory first by the player, then copied from there to
> video memory by the driver. This gets done for every frame.
> 
> The offscreen functionality is clearly there to avoid this overhead, but
> I can't yet figure out which applications will make use of this (nor what
> client level API functions are used so I can code my own tested).
> 
> Any help would be greatly appreciated!

some video devices (bttv for example) can DMA directly to video
memory.  these functions are provided for that case.  take a look at
the xawtv source.

Alex

> 
> Regards,
> 
> ---
> Kendall Bennett
> Chief Executive Officer
> SciTech Software, Inc.
> Phone: (530) 894 8400
> http://www.scitechsoft.com
> 
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