[MPlayer-users] TELECINE or not TELECINE?

[Corey Hickey]

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

-Corey