I have a problem with Avidemux under Ubuntu 10.10.
I played an MP4 movie, the first time it was perfect, the movie was played at normal speed and with a perfect quality.
Now when I start exactly the same movie (and other movies also) it's always going at slow speed. I didn't modify anything since the first time and i don't find how to play it at normal speed anymore.

Does someone know what could be the problem ?

Thank you in advance.