Originally Posted by Wizziwig
Most 120Hz sample-and-hold displays can also support lower refresh rates like 96Hz. On such a display you would repeat each frame twice followed by two frames of black. There would be no additional judder but pretty intense flickering from the low 48Hz effective refresh rate. This is what the Sony A1E does with 24p inputs. Motion resolution is improved since you've cut image persistence from 42ms to 21ms. The other approach would be to convert the 24p source to 60Hz just as if you set your disc player to 60Hz output. You then insert black frames every other frame just as for any other 60Hz source. You could do this on the Sony A1E as well by setting the disc player to 60Hz output. It will produce some juddering from the uneven 3:2 repeating pattern of the frames.
Is 650 lines of motion resolution enough? For movies, I don't think it matters much because the source has lots of motion blur to begin with. Just pause any movie during a high speed motion sequence and see for yourself. On 60Hz content with no inherent source blurring like video games, 650 lines is not enough. You will still see a lot of blurring on high speed motion compared to a CRT or Plasma but anything is a worthwhile improvement compared to ~300 lines of baseline motion resolution of a pure sample-and-hold display.
For those who didn't like OLED 24p motion without BFI, I don't think adding it is really going to improve anything with the current limitations. Supposedly they also improved their motion interpolation for 2018 (less artifacts) so maybe you can forget BFI and find some smoothing setting that you can live with.
This is why I always think to myself: UHD is pointless unless watching screenshots, since motion blur reduces motion resolution to below 720p levels, unless you turn on frame interpolation and even then, it's probably still less than 1080p. 1080p 120hz native would look sharper most of the time than UHD 60 fps let alone UHD at 24 fps.
Most movies have static cameras most of the time, filming people who are in focus and the centerpiece of attention, but ironically they are the least clear since they move.
So the whole image ends up blurry: out of focus parts (backgrounds) are inherently blurred but static, in focus is blurred from movement. You can't win. This is why UHD demos on TVs often show static content or at least very slowly moving.
BFI is also less effective unless you use FI as well. Actually what one needs to do is clean up the motion blur baked into 24p material to match the final persistence, whether that's the equivalent to 60hz or 120hz or 240hz effective. But removing motion blur is a quote "hard problem" according to researchers in the field. AI and machine learning will certainly keep improving things, I think frame interpolation is heading this way instead of naive Eulerian methods which have known artifacts. I'm interested in seeing what FI looks like on the latest TVs and projectors.
I find it rather sad that the best tool that exists to improve the clarity of film and television content, doesn't merit a shootout to evaluate which vendors have the best implementations.
BFI'ing un-interpolated low framerate content is just going to make judder stick out more like it does at the movies.