How do I know which paramter is the default for an ffmpeg filter?

by Rubin|Published March 31, 2025

I’ve noticed that some ffmpeg filters omit the name of parameters for certain parameters.

For example, you can write:

ffplay -f lavfi -i 'color=red'

rather than using color=color=red; or

ffplay -f lavfi -i 'color=white:size=1024x512, drawtext=hello, scale=500x300'

How do I tell which parameter is the “default parameter”?