Avisynth pre-processing assumeFPS

[Aludin]

I have a bunch of videos I need to sort thru, preferably at 2x speed but AssumeFPS doesn't appear to work on players that allow Avisynth pre-processing. Every other filter works, including changeFPS. Is an exemption made for anything that affects the duration or something?

I'd just use Potplayer's internal speedup function but that results in choppy playback.

[pandy]

check mpv or ffplay with

-vf "setpts=PTS/2"

, choppy playback may be a symptom for insufficient (too slow) decoding.

[Aludin]

check mpv or ffplay with

-vf "setpts=PTS/2"

, choppy playback may be a symptom for insufficient (too slow) decoding.

I'm not familiar with either of those, what are they? And it's not slow decoding. The same player plays Avisynth scripts with increased FPS perfectly smooth but chops up when using the player's own internal speedup.