I have recorded my desktop to upload to youtube. It comes out as a green rectangle

A well known problem per google.
Anyone recommend a good program to convert as I have never done this before.
Cheers
Steve
Dell Inspiron N5010 / Core I5 / ATI Mobility Radeon HD5400, LMDE Tracking Sid & Cinnamon Desktop
"Ubuntu is an African word meaning 'I can't configure Debian'"