Many suggestions of improvement

[Selur]

I am aware of the effect on how different max and min gop sizes can influence the compression, thanks.
I hoped for something more than the usual fps*10 stuff.

Won't change min keyint, since using fps seems wrong for normal content.
May I ask who recommends that and why? (I would understand values like 1-5, but fps seems like a bad idea.)

Will think about an adding an option to set, 'output fps'*10, but be aware that if you change the frame rate through filtering, this can change other settings.
i.e. for x264, lookahead is limited to min(gop_size,250) (<- in the source code of x264). So if you change the filtering to for example output 60fps lookahead would increase to 250, but would not go down when you later change the fps to 23.976. Similar b-frame and other settings can change if you change the fps while finding the right filtering settings. Also, the option will not be available when using Blu-Ray compatibility or similar.
=> not really sure if this is a good idea, but I will think about it.

Cu Selur