Win8.1-64 replacing Win7-32 on my HTPC running MC19 as multimedia app produces the most unanticipated problem: AMD Catalyst Control Center (video card app) suddenly lost its ability to change video brightness, contrast and colors as played by MC19. More specifically, the loss only happens when I use Red October HD rendering!
Configuration before upgrade:
AMD Anthon x4 CPU, AMD HD5670 video card with the latest version of Catalyst, Windows 7-32 Ultimate SP1, MC19.
After proper tuning this machine is able to play back HD video files up to 35Mbps bitrate with excellent performance in speed and colors. The Catalyst app is the main tool to control screen colors, while MC19 color controls are left in default. The purpose of the upgrade is to use a SSD as C drive running the new Windows.
Configuration after upgrade:
Same hardware but with SSD booting Windows 8.1-64 with latest version of Catalyst, MC19.
When using Catalyst (presumably a 64-bit version under Win8.1-64), it fails to effect any control over MC19 video screen when configured exactly as before. When I switched to Red October Standard rendering engine to test, screen control returns. Also, when I play video using Cyberlink Power DVD13, Catalyst is able to control its video color perfectly.
The issue with Red October Standard is it is simply not able to render high bitrate video - all kinds of smearing artifacts occur. So I must have ROHD to deliver high bitrate performance. With loss of Catalyst control over MC, video brightness & contrast is way too low, and colors are a bit off. I effect a temporary fix by using MC19 Color Controls. Also, playing around with madVR rendering engine does not offer a fix.
I post this issue because I believe a change of Windows from 7 to 8.1 should not cause such a problem to MC.