So i usually use the mp4 container to export my videos and i prefer this mainly because of youtube. I had some succesful exports but recently run into an odd problem, which i could only fix by using another container (wmv and mov worked fine):
Problem: Although everything is synchronized in the editor, when exporting the video plays back at half the real speed and fps. So encoding a 5 second part at resulted in a ~10 second clip that has audio for the first 5 seconds!
Info: I tried reencoding only a single file, ~1 hour long, 720p ~54fps* mp4 video, 48khz audio. The resulting file was roughly twice the time, 720p 25fps(!!) mp4 video, 48khz audio. Project settings automatically adjusted (so 720p, 54fps, 48khz)
Question: I can guess that converting 54fps to 25fps is probably what is slowing the video and doubling the time, but why does this happen? And why does it happen only with the mp4 container? Could it have anything to do with being in a PAL region?
* I wanted a 60fps file, but my capture software (plays.tv) didn't play nice (and recording directly to an external hdd was probably stupid on my part...)