Transmageddon Video Transcoder is a great media converter for Ubuntu.
It converts audio and video files, it has a simple interface, and it’s free.
Launch it from the applications menu.
The tool looks like this:
At the top you choose the input file which you want to convert.
choose the button and navigate to the file you want it converted then click Open.
it’s possible for you to see the input video properties just below the Choose Input File button.
Now grab the target format you want from the Output Format menu.
Right below that are the options for audio and video codec.
Choose the prefs you desire.
you’re able to choose different audio/video codecs with different qualities and formats.
After you finish choosing the tweaks you want, hit Transcode to start the conversion process.
It may take a while depending on the length of the video and the setting you choose.
You will find the output file in under Videos in your Home directory.
Easy, isnt it?