Have just edited short HD piece with seperate voice over. When exported as avi the sound drops out and the transitions where not smooth. I am still using MEP 14 Plus. I can export files to,windows media video wmv file
When you export to AVI this is high quality with no compression on file, the main difference using WMV file the quality is reduced and the video file is compressed. The reason the playback is not smoth is probably due to your computer. Try to close some uned application using (Ctrl Alt Delete keys) to close application also desactivate your antivirus dring playback.
Playing big file need more memory and better machine.
Just a thought, but try out the free trial version of MEP 17 HD Plus to see how you get along. If you do, extend it to a full 30 days, otherwise the fun will be over quicker than you like. Cheers, M o' L.