There are many ways to convert movies from one format to another as well as there are many apps for Macs, paid and free.
Many of those apps use ffmpeg (check your processes while program of your choice converting video file).

If you haven't already, install ffmpeg with H.264 support using Terminal:


One of the hardest apps to find is to convert MKV video to QuickTIme MOV format. ffmpeg does it with ease. Two hours video file converted within 2 minutes.

If you want to convert MKV video to QuickTIme format with video and audio codecs intact just enter the following in your Terminal window:


when you want to convert MKV video to QuickTime MOV format with ACC 5.1 audio:


to chop MKV file

where -ss 00:00:00.000 stands for beginning timecode format of the input.mkv file
and -t 00:10:00.000 end time code in input.mkv
In example above first ten minutes of the input.mkv video will be duration of output.mkv video.

Path to input.xxx and output.xxx files should be fully qualified unless you "cd" to the folder where input.xxx file is. In this case output.xxx file will be created in the same folder.There's no place like ~

Forgot to mention. To install MacPorts and save a lot of headache installing software, just visit the MacPorts at:
http://www.macports.orgThere's no place like ~

Convert image sequence to a movie:

Scale down movie:

Use Photoshop saved Curves to do a color correction:

Color-balance and scale your movie:

to name just a few available ffmpeg video filters.There's no place like ~