[Libav-user] Adjust fps

[Leandro Raffo]

I'm trying to remux a video changing its frame rate, but I'm a bit
lost in how to do it. This is what I have in mind:
Suppose I have a 20 fps video and I want to take it for example to 10
fps, should I drop every second frame (paket) and JUST multiply the
dts and pts by 2.

What if I want to go 3 or 7 or 13 fps? I'm guessing I should be
rescaling the dts and pts using the input_stream time_base or
avg_frame_rate to get something reliable, but I don't know how!