[FFmpeg-user] Documentation and feature request

[Paul B Mahol]

On 4/15/19, Michael Koch <astroelectronic at t-online.de> wrote:
> Hi all,

[...]

> Feature request:
> -- Decay filter, makes short flashes of light appear longer, with an
> exponential decay curve. Like on an analog oscilloscope screen with long
> persistence time. Could be used for videos of the night sky to make fast
> meteors appear longer. Should work as follows:
> For each pixel do:  Multiply the RGB values from the previous output
> frame with a decay constant in the range [0..1], for example 0.95. Use
> these RGB values for the next output frame. But if the RGB value from
> the next input frame is brigher than this, then use the brighter value.

Implemented as lagfun filter.
See ffmpeg-devel mailing list.