Command to keep only certain segment of a .ogv file required!

[Rytron]

Hi.
I can to keep from 0:04 to 0:15 of video.avi with the following command:
mencoder -ss 0:04 -endpos 0:15 -oac copy -ovc copy video.avi -o part1.avi

How can I do the same with a .ogv file?