Specify FPS from commandline

[WampyCakes]

Description of proposed feature

You should be able to specify what frame rate to use when rendering from the commandline. Something like --fps 30

How can the new feature be used?

Setting fps without modifying the manim script

[leotrs]

Not saying this is a replacement for the requested feature, but you can set FPS independently of quality using a config file.

[behackl]

I've always been wondering why the fps couldn't be set from the CLI -- thanks for opening an issue. It should be easy to add a flag; but we shouldn't do so before #1013 is merged.

[WampyCakes]

@leotrs The problem is that quality sets both resolution and fps. I think we should be able to use quality flags and also be able to independently set fps and resolution from the commandline. I am in a situation atm where that would be helpful, and as it pertains to rendering, it belongs as an option in the command. You don't always want to have to modify your config or script for quality.

[leotrs]

Yeah that's fair. I think in this case it is warranted. However, I would advise against the proliferation of CLI flags in general...

[jsonvillanueva]

I've always been wondering why the fps couldn't be set from the CLI -- thanks for opening an issue. It should be easy to add a flag

Agreed it would be easier -- in fact, I've already done some work for that because it didn't make sense to have --webgl_updater_fps and not a general fps for each renderer.

[jsonvillanueva]

Click isn't in the spirit of freedom with the CLI. It's supposed to standardize the CLI to make intuitive sense with other POSIX compliant CLIs. In some cases, it would be very against Click's design to implement it like Argparse currently does -- so instead I opted to break the CLI's API and do some housekeeping/reorganization. The flags should all be there and if there was a test case written for it, it should still work.

fps is one example where it doesn't work in the cairo renderer (but webgl should work) and I'd have to write a video test or something to ensure proper functionality in the future

[jsonvillanueva]

This is now fixed in Cairo rendering in #1013, try using --fps 29.97, or --frame_rate 29.97