KMS Textured Video

[Roland Scheidegger]

On 01.09.2009 12:52, James Cloos wrote:
> Alex> What's the problem with textured video?  It should perform as well
> Alex> or better than the overlay without all the limitations.
> 
> It is not a question of performace but of features.
> 
> The overlay supports 8 formats and 22 attributes (more on hw which has a
> tuner) whereas the textured video supports 4 formats and only a single
> attribute.
> 
> Given the tables in radeon_textured_video.c, I'd say r300 is the minimum
> prefered hw for textured video support and r200 is the minimum useful hw.
Ok, fair enough. That said, from the basic video features r200 is only
missing gamma, and that should be doable if someone feels inclined to do
it I believe (by using lookup tables for gamma), though it would use the
second shader phase on r200 and double the amount of texture and alu
instructions - that could be a performance problem for the r200 based
IGPs I believe (at high resolutions).
For r100, I'm not sure if it's possible to do much (clearly gamma is
out). It currently is using the hw-based yuv-rgb conversion, so if you'd
want to change colorspace conversion (colorspace/hue/saturation
attributes) you'd need to switch to shader conversion. Contrast and
brightness settings alone might be easier. When I briefly looked at
shader based colorspace conversion when I did the r200 shader conversion
code, it seemed impossible on r100 - mostly due to the missing input
modifiers, r100 can only do complement (so it's impossible to have a
color constant with both negative and positive components), and the chip
might not handle (temporary) negative outputs neither anyway.

Roland