[FFmpeg-user] alternating checkerboard

[Paul B Mahol]

On Tue, Feb 9, 2021 at 9:45 AM Mark Filipak (ffmpeg) <markfilipak at bog.us>
wrote:

> On 02/09/2021 03:14 AM, Michael Koch wrote:
> > Am 09.02.2021 um 04:49 schrieb Mark Filipak (ffmpeg):
> >> I don't know the details of the filters that work on pixels ('blend',
> for example). I hope a
> >> knowledgeable person will respond with suggestions.
> >>
> >> I'd like to experiment with a filter that mixes pixels from 2
> progressive streams on an
> >> alternating checkerboard pattern. Got any suggestions?
> >>  _________________    _________________    _________________
> >> |# # # # # # # # #   | % % % % % % % %    |#%#%#%#%#%#%#%#%#
> >> | # # # # # # # #    |% % % % % % % % %   |%#%#%#%#%#%#%#%#%
> >> |# # # # # # # # # + | % % % % % % % %  = |#%#%#%#%#%#%#%#%#
> >> | # # # # # # # #    |% % % % % % % % %   |%#%#%#%#%#%#%#%#%
> >> |# # # # # # # # #   | % % % % % % % %    |#%#%#%#%#%#%#%#%#
> >>
> >>
> >
> > Have a look at the "maskedmerge" filter. In your case the mergemap file
> would contain a pattern of
> > 0's and 255's. This file can be generated with "geq" filter (see the
> example in chapter 2.107).
>
> Thanks for the suggestion. Actually, it appears that the 'blend' filter
> does what I want, but I'm
> still testing to be sure.
> blend=all_expr='if(eq(mod(X,2),mod(Y,2)),TOP,BOTTOM)'
> 'blend' appears to input 2 frames in 2 streams and output 1 frame (with
> unknown PTS). 'tblend', on
> the other hand, appears to take 2 frames in 1 stream and output 2 frames,
> not 1 frame, (again, with
> unknown PTS). It sure would be nice if these filter functions were
> adequately documented, especially
> regarding how they determine output PTS. But you shouldn't listen to me
> because, to quote the
> authorities: "That makes no sense".
>
>
Why you write unknown PTS? What you are talking about, please do not be
dense.

PTS is always deterministic from these filters.



> > Michael
> >
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>
> --
> I don't have a dog.
> And furthermore, my dog doesn't bite.
> And furthermore, you provoked him.
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