For those who also have slow video I can inform you that DM will return the old video format
The whole thing is actually pretty weird. I mean the way the animations in some top AVN games behave. We talk about some brakes/freeze and CPU core load, but really it's just ridiculous 5-20 megabyte clips and I can tell you that's in most AVN games I've played.. And the bitrate of such clips is far from prohibitive. And even (in the vast majority of games) they are made not in 4K, but in regular 1080p. Besides, such animations are packaged in a standard video container supported by most OS, software players and devices themselves. So where do these brakes come from? Well, yes, maybe problems with codecs and so on...But in general something is wrong here..
And it seems to me that the RenPy engine is more to blame for all this, because tiny clips with animation (if you run them separately in any program video player) themselves, as a rule, do not slow down. The only thing that slows me down (and that's only on an old laptop with I5 Core) is some 4k videos with high bitrate, but there it is at least logically explainable, which can not be said about tiny video clips with game animations.
P.S. I'd still understand if the devs put us the "raw animation" as they create it in DAZ3D/Blender, I wouldn't be surprised if the whole thing weighs a few gigabytes before optimization and compression, and then some playback lags would make at least a little bit of sense..BUT! People are complaining about tiny video clips! that a priori shouldn't playback lags, unless of course you're using some ancient Pentium 166..