[MPlayer-users] Frame interpolation

[Greg Trounson]

> Grant pisze:
>
>> But the reason I started looking into this is the intense flashing
>> effect I see when an intricate object is moved across the screen.  I
>> was told that is part of 24p judder.  Is that true?
>
> But 24p judder isn't there because 24fps is displayed at 24fps but
> because 24fps is displayed at... 60fps. So it needs to be interpolated
> and there is 3:2 telecine introduced which do interlaced 60i from 24p
>
> I've read that some better TV's do 3:3 or even 4:4 so it view 24p at 72i
> or 96i and that have no judder at all.
> http://www.avforums.com/forums/plasma-televisions/714524-some-one-tell-me-about-24fps-thing-judder-etc.html
>
> That's why some dvd/bluray players have 24p mode and some TV have it too
> - to go around that problem without any interpolation.

3:2 pulldown such as that applied when converting from 24fps to 30fps does
add judder, but I live in a territory where 25fps is the norm (PAL as
opposed to NTSC).  Here no pulldown is applied at all - the whole film is
just sped up 4%.  This has the effect that movies converted to PAL are
shorter than original, and unless pitch correction is applied the sound is
one semitone too high.  That is why 24p mode is useful for us.

The judder I see is both in the actual cinema (at 24fps with all the
Persistence of Vision effects) and on a PAL television.  The frame rate is
just too low for the brain to perceive smooth motion.

But I agree with you that 3:2 pulldown certainly does make things slightly
worse on the few NTSC DVDs I own.

Greg