View Single Post
Old 18th August 2017, 19:38   #22110  |  Link
aufkrawall
Registered User
 
Join Date: Dec 2011
Posts: 1,812
Thx a lot for D3D11VA support, nev.
I did some tests and here are my conclusions vs. DXVA2 (copyback) regarding quality on a GTX 1070 with driver 385.28 on Windows 10 Creators Update 1 + madVR (deband off, dithered 8 bit output):
  • DXVA2 native doesn't show banding anymore (?) with HEVC 10 bit Rec.709 content
  • DXVA2 native shows most excessive banding with HEVC 10 bit Rec.2020 HDR content
  • It still shows nasty chroma blur with H.264 8 bit
  • I don't have a proper sample to test chroma blur with 10 bit content, so can't say if it would also show chroma blur with DXVA2 native (I personally would expect the worst)
  • It seems DXVA2 native doesn't increase banding anymore (?) of 8 bit H.264 sources
  • D3D11VA doesn't seem to show any banding at all with any of the mentioned content
  • D3D11VA also doesn't show any chroma blur
  • Both points also apply to DXVA2 copyback (of course we already knew that)

And now, a interesting point which has often been excluded: performance.

I assumed my graphics card's power consumption by multiplying the average percentage value of the reported power target with the card's measured 100% power target, which is ~180W for this MSI 1070 Gaming X. Nvidia Inspector and hwinfo64 can read out values in Watts, but they don't seem to be realistic for some reasons (way too high).
I again tested with a HEVC 10 bit Rec.2020 HDR 4k 60fps video, downscaled to 1440p with reasonable quality settings.

d3d11va: ~32% Power -> ~58W ~55% GPU usage @ 1.45GHz @ 2.3GB VRAM
dxva2-copyback: ~54% Power -> ~97W ~68% GPU usage @ 2GHz 2.5GB VRAM

So, copyback mode can have a huge impact on power consumption and performance, and even may prevent you from using better madVR quality settings.

-> D3D11VA seems to be golden.
aufkrawall is offline   Reply With Quote