[FFmpeg-user] Decombing via screening

Mark Filipak markfilipak.windows+ffmpeg at gmail.com
Tue Apr 14 12:56:36 EEST 2020

On 04/14/2020 05:26 AM, Paul B Mahol wrote:
> On 4/14/20, Mark Filipak <markfilipak.windows+ffmpeg at gmail.com> wrote:
>> On 04/14/2020 04:23 AM, Paul B Mahol wrote:
>>> On 4/14/20, Mark Filipak <markfilipak.windows+ffmpeg at gmail.com> wrote:
>>>> How do I combine two combed half-pictures so that the resulting picture
>>>> is screened?
>>>> Combed input frame:
>>>> 11111...
>>>> 22222...
>>>> Desired output frame:
>>>> 12121...
>>>> 21212...
>>>> It occurs to me that I need to unweave the half-pictures, line-double
>>>> both, screen both via pixel-sized screens that are offset by 1 pix, then reweave them.
>>> Look at weave, doubleweave, separatefields and so on....
>> Thanks. I'll run them through my tester.
>>>> I've not found a line-doubling filter and I've not found a screen method
>>>> that actually works.
>> Actually, after I posted, I thought of bob. I think bob line doubles.
> I think you can double lines with separatefields,scale combination.
> You just need to set right size args to scale filter and use nearest
> neigbour interpolation
> for doubling lines.
> I still think that what you do is wrong thing to do.

To which do you refer? 5-5-5-5 telecine (which is the overall architecture) or screening combed 
frames (which is the final step)? Actually, what I already have running is better than what MPV 
and/or my TV produces; better than p24->p60 and better than 4-6-4-6 telecine (and much better than 
2-3-2-3 telecine frame doubled to 60fps of course).

> Why? mpv player already have various interpolation algorithms for
> X->60 progressive upsampling.

What about people who don't use MPV? What about PowerDVD?

> Note that they are not motion ones, as that one is very fragile and slow.

What do you have in mind, Paul? I don't care about slow. I have a very large, very fast system and 
can mount many vdisks that I can run overnight while I sleep. However, I'm not too keen on "fragile" 
but maybe I can noodle out a solution to fragile when I see it. After all, I'll have you to help me. :-)

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