[FFmpeg-devel] Vignette filter limitations...

[Paul B Mahol]

On 8/27/17, Evert Vorster <evorster at gmail.com> wrote:
> Hi there.
>
> The program's name is nona, and it is distributed in source code form with
> Hugin.
> http://hugin.sourceforge.net/docs/manual/Nona.html
>
> The source code and descritpions is available here:
> http://hugin.sourceforge.net/docs/html/index.html
>
> I hope it helps?

How is one supposed to use it to change vignetting?

>
> On 27 August 2017 at 13:35, Paul B Mahol <onemda at gmail.com> wrote:
>
>> On 8/27/17, Evert Vorster <evorster at gmail.com> wrote:
>> > Hi there.
>>
>> Hi,
>>
>> >
>> > I have asked this question on the ffmpeg-users list, but it's been oddly
>> > quiet on this front.
>> >
>> > I am trying to create a ffmpeg command line that re-maps and stitches
>> > together footage from the Samsung Gear 360 camera. The basic methodoly
>> can
>> > be applied to any 360 view camera. The reason I am doing this is that
>> > the
>> > software that is available to do this is closed source and extremely
>> > expensive. For a hobbiest, this is a bad situation.
>> >
>> > First thing I do, is to load a specially crafted series of frames in
>> Hugin,
>> > and perfectly map the lenses.
>> > Then I make the remap files that the ffmpeg remap filter uses with nona
>> -c.
>> > I hand craft a alpha map to do the blending between the lenses, and the
>> > results are really good.
>> >
>> > Unfortunately I have a real problem with vignetting.
>> > The vignette filter in ffmpeg seems to have some room for improvement.
>> > In Ffmpeg there is only one variable, and the x,y center. This allows
>> > for
>> > only one type of vignetting correction with the "backward" option set.
>> >
>> > In Hugin (and the panotools) the lens is described with 3 variables, and
>> an
>> > x,y center. This enables the vignetting strength to be described as a
>> > custom curve.
>> >
>> > If you are curious about the project, this is the github page, with
>> > examples.
>> > https://github.com/evertvorster/dualfisheye2equirectangular_ffmpeg_remap
>> > There are example .pto files, that when loaded in Hugin show the lens
>> > chataristics of the Samsung Gear 360 lenses, and some sample footage to
>> > test on.
>> >
>> > How difficult would it be to port the panotools' vignetting correcting
>> > filter into ffmpeg?
>>
>> How it is actually named?
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>>
>
>
>
> --
> Evert Vorster
> Isometrix Acquistion Superchief
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