is there any Time function to gat a duration from string ?

I get a string back from ffmpeg : "00:00:03.10" ( "hh:mm:ss" )
which class should I use to get it converted into 3.10 sec ( float)

thanks for your feedback

I tried :
output = "00:00:03.10"

output.split(':').inject(0){|a, m| a = a * 60 + m.to_f}
=> 3.1

is there any better way ?

You could convert the string to a time object and pick out the
specific parts you want. This might come in handy if you want to store
the time in the database at some point.