[MPlayer-users] TELECINE or not TELECINE?

[D Richard Felker III]

On Thu, Oct 09, 2003 at 01:47:13PM -0700, Corey Hickey wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> Rainer Koehler wrote:
> >Hi list,
> >
> >I have some pretty big (about 700MB) mpg-files that I want to encode
> >in divx to save space.  However, mencoder prints messages about "3:2
> >TELECINE" and "Progressive seq" every few seconds (logfile attached).
> >Using -ofps 23.976 or the pullup filter doesn't change anything.
> >Mplayer prints the same messages, but the video looks fine.
> >
> >Can anybody tell me what's going on here?  Can I do something about
> >it, or should I simply ignore the messages and encode it just like
> >that?  The output looks ok, but I want to make sure I don't screw up
> >anything before I delete the mpg-files...
> >
> >Thanks,
> >Rainer
> >
> 
> 
> From looking at the frame numbers in your log, it would appear that most
> of the progressive sequences are only a second long; I've found this
> often happens at scene changes on some DVDs, but since the log also
> shows them to happen at 1%, I might also guess that you're seeing the
> intro part of the movie or something. Either way, take a close look at
> your source file and see if you can see the interlacing then (in cases
> like this it might be hard to even notice if your eye isn't trained to
> watch for interlacing).
> 
> Once you find the interlacing, you should figure out if it's
> hard-telecined or not. Read this if you don't know what I mean by
> hard-telecine:
> http://mplayerhq.hu/pipermail/mplayer-users/2003-July/035503.html
> (note that the last two paragraphs are obsolete)
> 
> Play that part of the video with -fps 1 and look closely at the
> pattern of interlaced frames. If every single frame is interlaced, then
> there's no telecine to remove, and you'll have to decide between using
> a deinterlacing filter (pp=lb, etc.) or just leaving those few frames
> interlaced.
> 
> If some but not all of the frames are interlaced, then you
> ought to be able to de-telecine using either softpulldown+ivtc or
> pullup. The usual sequence of progressive and interlaced "frames" that
> you see in a hard-telecined sequence is:
> p,p,p,i,i,p,p,p,i,i .... etc.
> I say "frames" because really it's a sequence of alternate fields, but
> for our viewing mplayer combines them into frames. Other telecine
> patterns might also be workable, but I haven't encountered one; Rich
> could explain further.
> 
> If you eventually choose to use one of the telecine filters, you should
> make sure to apply them before cropping/scaling. Doing otherise can be
> problematic. For example:
> -vf softpulldown,ivtc=1,crop=708:358:6:62,scale=672:288

Nice advice. You can also use the pullup filter now (it supports mixed
hard+soft telecine!) but it won't (yet) work with -ofps 23.876. I'll
fix that later if I can think clearly enough to work out the
input:ouput frame ratio regulation right...

Rich