(2021-04-07, 19:07)mauromol Wrote: After all, motion compensation and frame rate conversions are two different things, I just wanted to say that motion seems to be smooth for me even without frame rate switching, perhaps also due to my use of Motion Flow. Please let's leave the usual flame war regarding frame interpolation yes/no out of scope.
Yes and No. Decent Frame Rate conversion solutions (as used to convert between 50 and 60Hz content for broadcast frame rate conversion) usually use motion compensation with some form of vector-based motion tracking (either using block-matching or Phase Correlation assisted Block-matching - these are devices like the GVG - previously Snell - Alchemist PhC or the For.A FRC-8000 etc.).
The vector tracking is to allow for motion compensation to be used in the frame rate conversion - you basically analyse the source frames at their native frame rate, track moving picture elements and find out their motion vectors, and use this information to interpolate the new frames, using motion compensation (rather than just weighted linear blending between frames).
Frame rate conversion (other than integer-based frame repetition) without block or pixel-based motion detection & compensation usually falls back to crude motion-adaptive stuff which really doesn't look great - using different amounts of blending between fields and lines adaptively, based on motion. (80s-style 4-field 4-line adaptive stuff uses that - as do cheap frame rate converters in use today), and then in its most crude form, without motion adaption, frame rate conversion usually just frame drops/frame repeats (which is usually what happens on Kodi platforms when content is output at a non-native, or non-integer multiple of native, refresh rate)
Motion Flow is a form of frame rate conversion - it's converting the input frame rate of the video it receives to a new frame rate (from 24, 25, 50, 60Hz etc.) to a new frame rate (50, 60, 100, 120Hz usually). It does that using algorithms that - I believe - use motion compensation to improve the interpolation.
The issue with 25/50Hz content played at 60Hz in Kodi is that the frame repetition approach is used (50Hz stuff usually gets converted to 60Hz by repeating every 5th frame - giving you 10Hz judder) and because MotionFlow is optimised to frame rate convert real-world motion - not real-world motion with added 10Hz frame-repetition motion artefacts, it smooths things out but has even less of a chance than normal to get things right. The MotionFlow algorithm can improve this - but look at any smooth linear motion (Say a lower third scrolling ticker on a news channel properly deinterlaced to 50Hz) and you see it can't remove the artefacts fully.
Effectively you are doing two frame rate conversions back to back - one in Kodi, and one in MotionFlow.
This isn't a MotionFlow flame war - I'm more than happy for others to use MotionFlow (I'm aware that I'm sensitive to the artefacts that the processing introduces, and others aren't) - but I think it's important to acknowledge where devices like Sony TVs still have limitations (and not playing back content frame-rate matched is a real limitation for many of us). MotionFlow may mask these, or mitigate them a bit, but the only real way to remove them is for them not to be there in the first place.