[Xorg-driver-geode] How to calculate the video overlay size? (xf86-video-geode & xf86-video-ati)
Cui, Hunk
Hunk.Cui at amd.com
Wed Aug 11 01:14:51 PDT 2010
Hi, guys,
In xf86-video-geode:
lx_video.c -> LXCopyPlanar function, some codes make me confuse,
(
http://cgit.freedesktop.org/xorg/driver/xf86-video-geode/tree/src/lx_vid
eo.c#n224 )
YSrcPitch = (width + 3) & ~3;
YDstPitch = (width + 31) & ~31;
UVSrcPitch = ((width >> 1) + 3) & ~3;
UVDstPitch = ((width >> 1) + 15) & ~15;
USrcOffset = YSrcPitch * height;
VSrcOffset = USrcOffset + (UVSrcPitch * (height >> 1));
UDstOffset = YDstPitch * height;
VDstOffset = UDstOffset + (UVDstPitch * (height >> 1));
size = YDstPitch * height;
size += UVDstPitch * height;
What is the formula for reference?
How to define and calculate the YDstPitch and UVDstPitch?
And in xf86-video-ati:
http://cgit.freedesktop.org/xorg/driver/xf86-video-ati/tree/src/radeon_v
ideo.c#n2940
The new_size(ATI) have same principle with size(Geode), how to explain
it?
Thanks,
Hunk Cui
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