[FFmpeg-user] Objectively best deinterlacer?

Leo Izen leo.izen at gmail.com
Fri Jan 24 07:18:48 CET 2014

On 01/22/2014 03:47 AM, Carl Eugen Hoyos wrote:
> Leo Izen <leo.izen <at> gmail.com> writes:
>> Is there any filter which is objectively best at
>> deinterlacing? I like the results from -filter:v 'pp=fd'
> Sorry, but imo it is ridiculous to compare fd (which
> is not a true deinterlacer) with yadif.
> And yes, a deinterlacer has to double the framerate
> for optimal results, an option to avoid that exists,
> please rtfm.
> Carl Eugen

I did not realize that all deinterlacers double the framerate. According 
to the manual, which I did read, yadif has an option "mode" which 
defaults to "send_frame" or "output 1 frame for each frame." I figured 
that because yadif defaults to send_frame, it must be the most basic 
option (now, I know, this is not the case). I also figured this was the 
case because "pp=fd" also sent frames at a 1:1 ratio (and I didn't know 
fd isn't a real deinterlacer.) Thus, I was basing my observation off 
this documentation and the experimental evidence, meaning that when I 
used default options and I did a drop-in replacement of yadif with 
w3fdif then my output framerate doubled. I didn't realize that dropping 
every-other frame would have been the preferred option anyway.

On 01/23/2014 01:42 AM, Robert Krüger wrote:
 > why do you use blend with w3fdif and not just discard every other
 > frame if you're deinterlacing 60i->30p by using the -r output option?
 > I don't see what you gain by blending in terms of quality.

I didn't realize that would be the best option. Also, I didn't realize 
that I was deinterlacing 60i -> 30p rather than 60i -> 60p (which I know 
wouldn't preserve full quality anyway.)


Now, both those being said, I now feel completely confused about 
deinterlacing (what I thought I knew before I guess I don't.) Let me ask 
a much more basic question that I had asked before.

Using yadif, what output framerate options would I use to deinterlace 
60i input (actually 59.94, but whatever)? Would I add "-r 29.97" or 
should I let it use its default of 59.94?

Also, sorry if message sounds angry, I don't intend it to sound that way 
but however I reword it, it ends up reading like that in my head.

Leo Izen

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