After more observation. It looks like nothing can be done except getting a new card
. If I restrict the video size to 1080p, then I can get smooth playback up to SoftCubic, but not Lanczos/Spline. Upload/render quite always looks ok (5/8 8/8) even if I use Lanczos/Spline on fullscreen(2560x1600), but it skip like crazy. This sounds like a useless report (even to me) but I do want to let you know that it does not show any improvement over other revision. The upside of this revision is that I can't distinguish the result of each scaling method (except nearest neighbor) for some reasons.
Anyway, I can live with Bilinear for now. Great job Madshi
. I'm looking forward to subtitle support too.
EDIT: I was typing when you post. I'll definitely try what you suggest and report back on any improvement.