[Video FPS] Include speed up/down next existing to 3:2 pull up/down

James, could you include video FPS speed up next to existing 3:2 (or other) frame duplication?

Many video applications offer possibility to speed up video to match (comon divisor) refresh framerate of the TV, as opposed to 3:2 pull down solution.

This would enable silky smooth playback before Apple enables 24p output.

How would that work: Currently, aTV is outputting 60Hz by default. That means, all films are presented using frame duplication. Only 30/60fps home videos are smooth.

If you set ATV to output at 50Hz, old PAL films will play smoothly by default. 24 and 23.9xx films can be sped up to 25fps. You will not notice the 4% difference. And if you apply filter to audio, even the small chipmunk effect can be eliminated. This will not be an option for people using pass through audio. Also, 30/60Hz home videos will have to be played with duplication. Still, worth implementing, in my opinion.


Framerate manipulation and MotionFlow are very different approaches to achieve the same thing: smooth (jitter / judder less) playback.

MF calculates (makes up) additional frames without altering the existing frames coming from source (aTV, BluRay, computer).

Imagine you are watching 30fps video on a TV set to 60Hz. With MF disabled, Tv would display 60 frames per second as follows: 1-1-2-2-3-3-4-4…
When MF is enabled, TV calculates a frame that is half way between frame 1 and 2. Let’s call it frame 1’. Similarly, frame 2’ is calculated between frame 2 and 3 and so on. The displayed sequence looks something like this: 1-1’-2-2’-3-3’-4-4’… This results in smoother (sort of high framerate) video playback. However, some people (including me) do not like the resulting ‘soap opera’ affect, because it doesn’t feel cinematic anymore.

Framerate manipulation
FM manipulates video framerate to match refreshrate of TV (smallest common divisible, actually). If you do this, +/- 4% speed up/down will go unnoticed. This is what is done in the (post-)PAL land.

The rest is described in my first post. The reason why I’m so sensitive is that I live on the old continent and the TV always done framerate manipulation which resulted in situation when myself, and many others, have never actually seen jerky (ie 24 → 30pfs converted) video. That’s why Infuse in one of their replies said “The output seems pretty smooth to us…” while there are others who see it as quite jerky. :wink:

Frame duplication
FD is what needs to be done in the (post-)NTSC land. That is what Infuse currently does (keeping in mind that aTV is set to output at 60Hz by default). More on this you can see in this video: Understanding Pulldown (Increase Your Nerdiness) - YouTube. Very nerdy! :wink:

I’d like to see this feature too.

Purists might not want the 4% speed up. But that’s been the standard for DVDs for decades. It’s a legitimate solution to the 24p output limitation.