MPEG2 DXVA 1 decoding broken in latest ATI and NVIDIA drivers

[jakor]

Hello guys,
I'm currently researching in the field of DXVA decoding of different video formats and I found out one interesting thing. There is this mode DXVA_Mode_MPEG2_D which allows doing VLD decoding of mpeg2 streams, however with all ATIs and Nvidias I tried when enabling this mode VideoAccelerator returns caps for actually only C mode, which is not VLD compliant. And only good olde GMA 950 return correct caps, asking nvidia and ati engineers gave no effect, no available docs on that, can anyone subject or object my findings ?

[Kado]

I don't remember NVIDIA having mode D.
DXVA checker picure dated may 22 2008 (http://pwp.netcabo.pt/kado/dxva_checker.jpg). unknown drivers.

It seems that a geforce 8500gt supports mode d, cyberlink decoder supports mode a,b,c,d,vld,idct. are you sure that mode d is the same as vld?
Check this (http://bluesky23.hp.infoseek.co.jp/dxvac/en/vas.html) and this as well (http://forum.doom9.org/showthread.php?p=1124795#post1124795)

[Sulik]

In DXVA1, MPEG-2 ModeD does NOT mean VLD support:
Mode A: must include motion comp acceleration
Mode B: Identical to Mode A with sub-picture blending support
Mode C: must include motion comp OR iDCT acceleration
Mode D: identical to Mode C with sub-picture blending support

IIRC, the DXVA2 VLD GUID is the only one that guarantees VLD mode support, and is also supported in DXVA1

[jakor]

thanks for the information !
8500 GT doesn't seem to have support for MPEG2 VLD, but what card does ?

[gowthamhk]

Even Mode C might support VLD. In MPEG-2, all A,B,C and D modes may support VLD which depends on particular hardware. You need to figure out only by probing.

I have seen some Intel Boards for Atom processor support MPEG-2 VLD in all the modes

[tetsuo55]

you might be right, my card should support VLD but i dont have a VLD mode in dxva checker, but i do have a->d