[Intel-gfx] HD XvMC on i915

Xiang, Haihao haihao.xiang at intel.com
Mon Oct 19 04:47:23 CEST 2009

On Sun, 2009-10-18 at 06:34 +0800, Nathan A. Stine wrote:
> Friends,
> I was doing a little bit of poking around in the source and found that
> the i915 driver has a max size of 720x576 for XvMC acceleration of
> MPEG-2.  Changing this to 1920x1080 gave a clean compile and would still
> properly accelerate and display 720x576 content, but not 1920x1080
> content.  The video was heavily distorted and had a green overlay.
> Questions:
> 1) Is 720x576 a hardware limitation?  I am using a 945G chip.
> 2) If the answer to 1) is no, what would it take to extend the driver to
> be able to accelerate 1920x1080 content?
The documentation doesn't say there is a limitation. But some people
from other group say the shader for intra (shader 0) is never used. This
means the I-picture is decoded by fixed function.  However the I-picture
of 1920x1080 isn't decoded correctly. So maybe it is a limitation.

> 3) If the answer to 1) is yes, do any chip/driver combinations support
> XvMC for 720p/1080i MPEG-2 content?  The manpage only lists XvMC as
> supported for i915/965 and G33.  Is this current information?
All 965+ support XvMC for 1080i MPEG-2. In addition G4X+ support XvMC-VLD for 1080i MPEG-2.

> The motivation here is to relieve my CPU the burden of decoding
> 720p/1080i MPEG-2 content.  If an upgrade will do it, I'd be happy to
> look into it, but I wanted to see what my options were.
> Best regards,
> Nathan A. Stine
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