yep it is mpeg layer-3 , with a bit rate of 47kbps on audio, and video it is: 29frmaes/second and data rate of 117kbps...i think it is saved so i cannot edit that video...dont know
To the best of my knowledge, MPEG-3 is MP3.. audio only. I've never seen anything that offers to render to or from MPEG-3. This would explain your audio only problem As far as I know, Video can be rendered to MPEG-1, 2, and now 4.