[MEncoder-users] inverse telecine with 60 fps progressive video

[D Richard Felker III]

On Fri, Apr 08, 2005 at 09:28:50AM -0700, Scott W. Larson wrote:
> 
> > Not understanding how doing the right thing works isn't an excuse for
> > doing the wrong thing. :)
> 
> Except the "right" thing didn't quite work. It did produce the most
> interesting pattern so far. After the edit, I got a pattern of seven good
> frames with each eighth frame duplicating the seventh.

Perhaps the video actually has this many extra frames, to increase the
length by 1/7? Without seeing a sample I have no idea..

> Unless there are any more ideas about filters, I'll just adjust the
> troublesome EDL pts's by hand until they pass a pattern that the pullup
> filter can handle. Remember that pullup handles *most* of the edits
> perfectly so I know pullup and filmdint can handle most 60 fps telecine
> patterns. It may just be a matter of adding another case to their code to
> handle this particular pattern.

This is blatently false. pullup DOES NOT HANDLE 60P TELECINE
WHATSOEVER!! It will output the exact same sequence of frames you
input to it, if they're progressive. What's happening is that
_mencoder_ is skipping frames to drop down to only 24 frames per
second. If the phase of mencoder's skipping is lined up with the
telecine pattern, you'll get the exact right sequence. Otherwise the
results will be very bad and choppy. But NO INVERSE TELECINE IS
HAPPENING. -vf pullup,softskip on 60p content will give (aside from
minor errors here and there) identical output to using no -vf at all.

Filmdint on the other hand will do some skipping on its own to make
the output 24 fps. However, I don't think it will try to match up
which frames are duplicates in any sane manner.

> I will also extract a 60 fps clip of the edit that causes the failure and
> post it so others can see what I've been seeing every day for a couple
> weeks.

The only cause is that it's out of phase with mencoder's skipping.
There's nothing strange/bad about it.

Rich