VMR9 YUV->RGB color conversion issues

wozio · Mar 7, 2007, 09:20 AM

Hi

Since cat 6.6 ati has broken color conversion routines when doing StretchRect from YUV surface to RGB. As you probably know video coding standard defines 16 as reference black and 235 as reference white. Conversion YUV->RGB can be done in two ways, extending 16-135 to 0-255 or by leaving original levels (better way). Cat in version up to 6.5 did in latter way. After 6.6 it was broken that for SD sources levels were extended and for HD were left as original or vice versa depending on drivers release.

So main question: is it possible to fix it in some modified drivers and let user choose method?

Regards
Piotr

Dyre Straits · Mar 7, 2007, 03:41 PM

Quote:

Originally Posted by wozio

Hi

Since cat 6.6 ati has broken color conversion routines when doing StretchRect from YUV surface to RGB. As you probably know video coding standard defines 16 as reference black and 235 as reference white. Conversion YUV->RGB can be done in two ways, extending 16-135 to 0-255 or by leaving original levels (better way). Cat in version up to 6.5 did in latter way. After 6.6 it was broken that for SD sources levels were extended and for HD were left as original or vice versa depending on drivers release.

So main question: is it possible to fix it in some modified drivers and let user choose method?

Regards
Piotr

Greetings and welcome to DriverHeaven!

I'm not sure just what changed, but after reading your post I have to wonder if the changes ATI made in the drivers has anything to do with the introduction and development of AVIVO.

I've tried to confirm that, but haven't found anything as yet. If it IS related to AVIVO I wouldn't expect ATI to go back to the 'old' way.

Stay tuned....

wozio · Mar 8, 2007, 07:09 AM

Hi,

Just to clarify: as far as I know VMR9 isn't actually a couse of the problem, it just uses StretchRect (or mocomp routines which I believe uses the same code for converting color formats) for rendering video, that's why it is visible by using VMR9. In my code I use StretchRect to color convert and results are the same.

Maybe it is something with avivo, but when decoding this is just renamed dxva plus separate extensions so problem is strange. Why they changed routines? NVIDIA has switch in registry to control this...

Piotr

wozio · Mar 8, 2007, 07:11 AM

Oh one more thing: also possibility to switch video noise reduction would be very useful. Now it can be done by adding TRDenoise key to registry.

wozio · Mar 8, 2007, 07:31 AM

even one more thing :-)

You can easily test it in any video player using vmr9 (for example media player classic) and decoder with scaler such as ffdshow. Set output to some yuv and then change output video size, it should switch to different routines when hitting hdtv resolution even when source video is exactly the same. So color conversion routines in drivers are different for different surface sizes.

wozio · Mar 8, 2007, 05:08 PM

It's me again.

It's me again :-)

I tested it little bit more and it looks that for yuv surfaces with vertical size equal or more than 720 pixels StretchRect uses different conversion routines. Horizontal size doesn't matter.

Regards
Piotr

kobri · Mar 17, 2007, 02:14 PM

I'm having exactly the same issues, is there any solution ?

wozio · Apr 3, 2007, 06:39 AM

Nothing changed in 7.3.

Dwarden · Apr 3, 2007, 06:14 PM

one may wonder ...