[FFmpeg-user] How to drop every Nth frame?

Carl Eugen Hoyos cehoyos at ag.or.at
Sat Sep 28 14:44:10 CEST 2013

L. Lee <llee040 <at> sbcglobal.net> writes:

> This interested me because I am trying inverse telecine 
> on 30 fps source (I normally work on 60 fps telecined 
> 1080i sources). This was Carl Eugen's first reply to 
> the discussion:
> "Both the select and the fps filter allow this.
> If this is actually an inverse telecine process (for pal
> input), consider using pullup."

Sorry if I was unclear:
If you need an inverse telecine process, you definitely 
don't want to use the select filter.
Either use fieldmatch (I thought that it does not need 
the fps filter but I may simply be wrong), fieldmatch 
needs decimate iirc, it is relatively slow but is said 
to work extremely well for difficult sources.
The more old-fashioned way is pullup, as the documentation 
explains, it can only work together with fps, it should 
always be faster than fieldmatch and is said to perform 
worse (sadly no such samples were ever provdided, the 
claim / trolling stays though).

Consider providing a sample (not too short, some horizontal 
motion) if nothing works for you!

Regarding my original comment above:
While extremely unlikely, it was possible that the OP tried 
to drop every 25th frame from a "telecined" recording that 
was shown in PAL-country. This is very rare afaict, and was 
apparently not the case here.

Carl Eugen

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