[MPlayer-users] Re: slightly confused by mencoder output

Rich Felker dalias at aerifal.cx
Wed Sep 14 18:22:21 CEST 2005

On Wed, Sep 14, 2005 at 10:58:30AM +0200, Matthias Wieser wrote:
> > NTSC just happens to be 3:2, whereas PAL is 2:2
> That's the reason I wrote "but sometimes it would be better to use 
> ivtc" [for NTSC].
> I wrote "sometimes" because not every broadcast your TV Card receives is a 
> film with 3:2 pulldown.
> The disadvantage of ntsc is that you nearly always need to process the 
> video. For PAL you only have to use a deinterlacer if it's not film 
> content.

This is exactly what I was saying is false. PAL can be
2:2:2:2:2:2:2:2:2:2:2:3 pulldown, or sometimes even field-blended to
convert from 24 fps to 50 field/sec. You're right that fairly often
you get lucky and it's just sped up with 2:2 pulldown, but it has
nothing to do with relative advantage/disadvantage of PAL versus NTSC.

> > (with horrible speed-up)
> That's a bit esoteric because there are filters which are able to speed up 
> the audio without changing the pitch.

However this invariably damages the audio quality.

> > or 2:2:2:2:2:2:2:2:2:2:2:3. :) Also there's no guarantee 
> > that 2:2 PAL is in phase with the field pairing of the capture device.
> There is no formal guarantee but it works for 99,...% of all cases. To be 
> precise: I have never had any captured video which was out of phase. Oh, 

It's been reported on the list fairly often, and was important enough
that someone even made a filter for it..

> > Basically you always need some sort of inverse pulldown for film
> > content, regardless of whether you have NTSC or PAL.
> If you have PAL it's nearly always bad to use one of mplayers inverse 
> pulldown filters. It's nearly always the right thing to use no video 
> filter (film content) or to use a deinterlacer (You may call the latter 
> one a special inverse pulldown filter...).

A deinterlacer is NOT an inverse pulldown filter.


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