# (ffmpeg-utils)2.6. Syntax | Ratio¶

doc

Ratio

Official documentation says:

A ratio can be expressed as an expression, or in the form numerator:denominator.

Note that a ratio with infinite (1/0) or negative value is considered valid, so you should check on the returned value if you want to exclude those values.

The undefined value can be expressed using the "0:0" string.

I think it’s not commonly used in other modern programming languages, it’s not natural as a mathematical notation, and as you can see, it’s a very annoying format that requires more escaping than necessary:

[me@host: ~]$# Specifying with fractional: [me@host: ~]$ ffmpeg -y -i video.mkv -vf 'framerate=30000/1001' out.mkv
[me@host: ~]$# The following will have the same result..., but...are you happy with this? [me@host: ~]$ ffmpeg -y -i video.mkv -vf 'framerate=30000\\:1001' out.mkv


Therefore, I have no idea how good this is.