speed action slows down and then returns to real time. (smooth transition)

[videoedit]

{I am writing with google translate}

[ time flow balancer filter request ]

how to do
speed action slows down and then returns to real time. (smooth transition)

Even the example below is not exactly what I wanted!

1:1 to 1:0.5 passes very fast, it shouldn't be that way !!!

It is requested from 1:1 to be 1:0.9 => 1:0.8 => 1:0.7 => 1:0.6 => 1:0.5

The video below is closer to the main idea!

[videoedit]

this is kind of crazy!
changing the flow of time: D

real time FPS      (24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)+>(24)
time slowing rate   (1)+>(0,9)+>(0,8)+>(0,7)+>(0,6)+>(0,5)+>(0,4)+>(0,3)+>(0,2)+>(0,1)+>(0,2)+>(0,3)+>(0,4)+>(0,5)+>(0,6)+>(0,7)+>(0,8)+>(0,9)+>(1)
slow time FPS      (24)+>(21,6)+>(19,2)+>(16,8)+>(14,4)+>(12)+>(9,6)+>(7,2)+>(4,8)+>(2,4)+>(4,8)+>(7,2)+>(9,6)+>(12)+>(14,4)+>(16,8)+>(19,2)+>(21,6)+>(24)

A 10.9 second scene extends to 19 seconds: D

It can be used for key transitions.

I don't know how to convert this to a plug in
I don't understand from programming: D

[eumagga0x2a]

A user would probably expect the A/V sync to be preserved after the effect, which is not feasible in Avidemux (i.e. it would require a lot of fiddling with Audacity or a similar application to edit the audio track).

The other grave issue would be the effect looking like the next frame button being pressed in quick succession instead of increased temporal and spacial resolution in the slow motion part, probably not achievable without sophisticated AI stuff.