[MPlayer-users] Re: [-] Crop before deinterlacing OK?

[Guillaume POIRIER]

Hi,

On 7/8/05, RC <rcooley at spamcop.net> wrote:
> On Thu, 7 Jul 2005 10:34:40 +0200
> Matthias Wieser <mwieser at gmx.de> wrote:
> 
> > Less work for the deinterlacing filter.
> 
> In most cases, it's a nominal difference.
> 
> > I thought you only need to inverse teleine when capturing NTSC
> > movies. Normal NTSC TV broadcasts can be deinterlaced with pp=[md|
> > lb...], right?
> 
> You'll find that NTSC broadcasts are commonly telecined, also.  Inverse
> telecine filters don't have negative side-effects if the content is
> not telecined, so it's best to always include it.

I fought quite a bit against NTSC content for the past week. From my
perspective, even thought ivtc doesn't _harm_ strictly speaking when
the content is not telecined, putting it "blindly" is not what I'd
recommend. That's because when you ivtc, you most of times change
framerate back to mostly the original framerate of the movie. Now, if
you do not set the correct output framerate with "-ofps", you'll
either end-up with duplicate frames if you output with -ofps
30000/1001 and your ivtc source is at 24000/1001 fps, or you'll end-up
with an encoded video that misses some frames if your source doesn't
benefit from an ivtc filter (because it's not a telecined content).

So please-please-please, identify your source before launching the
encoding process.

I'll update the docs with my findings when I have more time.

Guillaume
-- 
A lie gets halfway around the world before the truth has a chance to
get its pants on.
 -- Winston Churchill