Downsampling 1080p to 720p

[Rahsten]

I have an 8GB 1080p .avi file that plays a little choppy on my MacBook. I have no issues with 720p files so I was wondering if there is a simple way to downsample the 1080p file to a 720p file??? Is there an app that (preferably free) that can do this on OS X?

Thanks for any help

 

[P-Worm]

mpeg streamclip should do it for you.

P-Worm

 

[Rahsten]

whoops, my bad. it's an mkv file. streamclip doesnt handle those. any suggestions for mkv?