BasicVSR++ temporal jumps at group boundaries

[ywcz1997]

I'm using VapourSynth/Other/BasicVSR++ to restore a DVD source. The output has noticeable temporal inconsistency – the background jumps every few frames, especially in long shots.

I suspect this is due to chunk processing. Increasing length to 150 makes those 150 frames coherent, but the jump reappears exactly between frame 150 and 151. It seems the model doesn't handle boundaries well.

Is there a way to process with overlapping windows (like a sliding window with crossfade) to smooth out boundary jumps? Or any other recommended approach to maintain temporal continuity across groups?

[Selur]

BasicVSR++ had nothing for this,... see: https://github.com/HolyWu/vs-basicvsrpp
Maybe something for this could be done through the newly scene change base 'only apply to' controls,... or something similar,...

Can you share a clip which allows to reproduce the problem?

Cu Selur

[ywcz1997]

I've attached a short clip showing the problem. I processed the DVD source with BasicVSR++ using length=15 and length=150. In both cases, pay close attention to the mist/fog in the background – you'll see noticeable jumps at regular intervals.

[Selur]

off to work now, but will look at it later after work,..