[FFmpeg-devel] [PATCH] avfilter: add radial and circular blur video filter

[Paul B Mahol]

On 7/17/20, Steinar H. Gunderson <steinar+ffmpeg at gunderson.no> wrote:
> On Fri, Jul 17, 2020 at 08:00:31PM +0200, Paul B Mahol wrote:
>>>> But crucial info is missing. How one build vectors?
>>> (point - center) * scale_factor + center
>> And how to pick scale_factor,
>
> It's a user parameter. scale_factor signifies how long the blur is.
> 1.0 is no blur, 2.0 means every point gets blurred out to twice the distance
> from the center.
>
>> more over how to make this recursive at all?
>
> It's only recursive in the formulation; the actual computation is iterative.
>
>   tmp_pic1 = blur_pass(orig_pic, scale_factor);
>   tmp_pic2 = blur_pass(tmp_pic1, (scale_factor - 1.0) / 2.0 + 1.0);
>   tmp_pic3 = blur_pass(tmp_pic2, (scale_factor - 1.0) / 4.0 + 1.0);
>   output_pic = blur_pass(tmp_pic3, (scale_factor - 1.0) / 8.0 + 1.0);
>
> Repeat as many times as desired until you get the quality you want.
>
> You can also be creative with the blend strength if you want a blur that's
> not a box blur.

I fail to see how this can be faster than current approach at same quality.

>
> /* Steinar */
> --
> Homepage: https://www.sesse.net/
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