[FFmpeg-devel] [GSoC] Motion Interpolation

Robert Kr├╝ger krueger at lesspain.software
Sat Aug 27 15:45:17 EEST 2016


On Thu, Aug 25, 2016 at 10:28 PM, Davinder Singh <ds.mudhar at gmail.com>
wrote:

> On Thu, Aug 25, 2016 at 5:01 AM Andy Furniss <adf.lists at gmail.com> wrote:
>
> >
> >
> > I am testing with a somewhat artificial sample in that it's a framerate
> > de-interlace + scale down of a 1080i master, though it is "real" in the
> > sense that I may want to repair similar files where people have produced
> > a juddery mess by using yadif=0.
> >
>
> thanks for testing.
>
> >
> > It's very fast and my old (2010 Panasonic plasma) TV can't interpolate
> > it without artifacting in a few places, it can interpolate a field rate
> > version flawlessly and both mcfps and minterpolate do a lot better with
> > a 50fps master version -> 100fps, though they are still not perfect.
> >
> > As well as being fast it has overlays of varying opacity and some
> > repeating patterns just to make things even harder.
> >
> > Some observations while trying to get the best result - given the number
> > of options only a small subset could be tested:
> >
> > aobmc vs ombc, vsbmc 0 or 1 = no real difference.
> >
>
> now our main focus will be on "better" motion estimation that removes
> artifacts in fast motion, rather than little tweaks like these.
>
>
> > Any me method other than epzs had far too many artifacts to be used.
> >
> > Raising search_param to 48 or 64 or 128 just causes new artifacts.
> >
>
> that hopefully could be fixed. working on it.
>
>
> >
> > Reducing mb_size causes new artifacts.
> >
>
> yes for higher resolution. for very smaller, it could be essential.
>
>
> > bilat vs bidir - similar but bilat has some artifacts on a still shot
> > near the end of the defaults sample uploaded. bidir sometimes has green
> > near the top of the screen.
> >
>
> i see that green line in other samples too. investigating.
>
>
> >
> > There are of course many small artifacts, to be seen by slowmo/framestep
> > for both minterpolate and mcfps. Viewing fullspeed mcfps artifacts less
> > on the car when it touches the edges than minterpolate. Frame stepping
> > shows mcfps doesn't blend/blur as much on really fast moving background
> > as minterpolate does.
> >
> > Included in the link below (which is a tar to stop google drive making
> > terrible low quality/fps previews) are the 25fps master file, mcfps
> > interpolation to 50fps, minterpolate with default options and
> > minterpolate with defaults + bidir.
> >
> >
> > https://drive.google.com/file/d/0BxP5-S1t9VEEM2VrTzlVdGZURVk/view?
> usp=sharing
>
>
> thanks :)
>
> DSM_
>
>
what is the way to best contribute with test cases? I have two samples that
I use for testing, so far the results look very, very promising but there
are still a few artefact problems, so these could maybe serve as a good
test case. In some cases the artefacts almost certainly look like there is
a bug in motion vector calculation as a very large area suddenly begins to
move in which really only a small part is/should be moving.

How do I make this available to you or other devs at this stage? Just trac
tickets or is it too early for that and you would like to work on this
differently? After all it is always a grey area, when this can be
considered solved, as it is a process of gradual improvements, so maybe
it's not well-suited for a ticket.

Let me know. Happy to contribute samples and some testing time here and
there.


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