[MPlayer-users] PAL interlacing

[D Richard Felker III]

On Fri, Jan 23, 2004 at 07:18:48PM +0300, Vladimir Mosgalin wrote:
> On Fri, 23 Jan 2004, D Richard Felker III wrote:
> 
> DRFI>On Fri, Jan 23, 2004 at 03:52:15AM +0300, Vladimir Mosgalin wrote:
> DRFI>> Can somebody please explain how PAL video is interlaced? I searched on
> DRFI>> this a little, but it seems that almost everyone is writing about 50fps
> DRFI>> video for the TV. I want to know, what is found on regular 25fps
> DRFI>> DVDs with every frame (or every second frame) interlaced?
> DRFI>> 
> DRFI>> Pattern in source film is (T1 B1) (T2 B2) (T3 B3) (T4 B4), speeded up to
> DRFI>> 25fps; how exactly 25 fps interlaced video is produced from it? Is there
> DRFI>> way to reverse it without deinterlacing?
> DRFI>
> DRFI>Interlaced video is NOT produced from film. It comes from TV/video
> DRFI>cameras. There's no process to be "reversed"; this is just how it
> DRFI>was originally recorded.
> 
> OK. Let's go to concrete examples. Yes, I've seen 25fps interlaced
> videos that were most likely recorded with cameras - film bonuces are
> often like that. But then I take "The Wall" PAL DVD and see that video
> is interlaced, even in animation sequences. You don't suppose they were
> recorded with camera, do you? I havn't seen NTSC version, only divx rip,
> which is poor quality 29.97 non-interlaced video were fourth frame goes
> twice - it was deinterlaced, so I don't know how it looked like on DVD.

This is telecine, which you'll encounted regularly in NTSC content.
But normal telecine (3:2 pulldown) doesn't occur in PAL. You might
find a few (very rare) PAL dvds with 3:2:2:2:2:2:2:2:2:2:2:2 pulldown
(12 frames that look good followed by 11 that look interlaced, and
repeating). I would expect this may be the case in "The Wall" since
speeding up the movie from 24 fps to 25 fps would damage the musical
content. Anyway -vf pullup can repair this sort of pulldown (but every
24th frame will be duplicated) or -vf filmdint might work.

Rich