[FFmpeg-user] Why was patch declined: Modified force_key_frames option to accept frame numbers?

[Nick]

Hi,
why was the "Modified force_key_frames option to accept frame numbers"
(2014) declined?

> https://ffmpeg.org/pipermail/ffmpeg-devel/2014-November/165167.html
You can even specify frame numbers in the current ffmpeg version using:
> -force_key_frames expr:gte(n,n_forced*96)
Using a framerate of 24 means a keyframe every 4s.
I think it is very useful to have something like

> /force_key_frames n:0,25,50,75,100/
Someone said that the frame numbers are not aligned for different video
qualities. Why?
If I have a constant framerate and I insert a keyframe at x-frame it
should be at the same time for all video qualities?