Because they're not that common when dealing with digital video signals from a PC, only analog.
Hmm, ok, maybe 25 fps is not that common, but 50.
- my video editor supports 50, but not 48
- most of the other recording software also support 50 fps (but not 48)
- most cameras record at 50 fps (good to mix with 50 fps gameplay)
at least in Europe?:
- TV
- some YouTube videos are at 50 fps. Almost as many as 60 fps, during there are almost no videos at 48 fps.
Why is 48 under Common FPS Values, during 50, which is more common, isn't?
I would add at least 50 fps to Common FPS Values.