how to get full av.open(...., options) options's document?

[Jackiexiao]

I know I can search https://ffmpeg.org/ffmpeg.html or use ffmpeg --help to find options,

for example

> ffmpeg --help
....
Video options:
-r rate             set frame rate (Hz value, fraction or abbreviation)
-s size             set frame size (WxH or abbreviation)

but we use video_size instead of s in code, How do I know the mapping relationship between them?

 options={
            'video_size': '640x480'
        })

[xiaofanku]

i wanI also want to know. I tried width, height, and vf, but none of them worked