[FFmpeg-user] Questions about w3fdif deinterlacing

Christian Ebert blacktrash at gmx.net
Sat Jan 18 21:52:49 CET 2014

* Carl Eugen Hoyos on Saturday, January 18, 2014 at 19:45:33 +0000
> Christian Ebert <blacktrash <at> gmx.net> writes:
>> Doesn't yadif have its own detection:
>> yadif=deint=interlaced
>> ?
> No, it does not have detection.
> MPEG-2 streams contain information about interlaced / 
> non-interlaced which is used by yadif if you set it so.
> The problem is that (where I live, and - I suspect - 
> where you live) *all* dvb streams are marked as 
> "interlaced" (because they are encoded with the 
> hardware encoder set to "interlaced"), no matter if 
> they are progressive (imagine a movie or soap) or 
> interlaced (sports, news).

This sounds like deint=interlaced reacts to a global flag whereas
the manual makes it sound like to work on a frame by frame basis:

1, interlaced
    only deinterlace frames marked as interlaced

>> and parity=auto is its default?
> The situation is similar although it should usually 
> be correct, real (dvd) streams with incorrect 
> parity information exist though.


>> Why would I want to run idet before yadif?
> I always trust my eyes, if you have to automate, 
> idet is the best / only possibility you have.
> Don't forget that it does not work well with 
> telecined streams.

In practice this means that I just run idet before yadif in the
filter chain:
-vf idet,yadif
and yadif will deinterlace (or not) on a frame by frame basis?

Or what is the difference between

-vf yadif=deint=interlaced


-vf idet,yadif


Thanks for your explanations.

\black\trash movie         _SAME  TIME  SAME  PLACE_
 --->> http://www.blacktrash.org/underdogma/stsp.php
\black\trash audio   _ANOTHER  TIME  ANOTHER  PLACE_
--->> http://www.blacktrash.org/underdogma/atap.html

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