What are the full specs. of the files in your Timeline, and what was the Project Preset chosen at New Project?
They are avchd files (from a sony handycam). As far as the project, I chose new movie. Very basic I suppose. Thanks !
At New Project, did you choose the AVCHD Stereo Preset?
When you dragged your Clips to the Timeline, did you have a red line above them? If so, that indicates that the Project Preset did not match your AVCHD footage.
Good luck, and let us know a bit more, please.