I got a similar problem:
I have a professional footage with WAV audio file previously mastered in a music production software.
It is synch up with the original video file. On playback in Premiere CS5 the volume gain is perfect (0 db). The problem is when I export it to a H.264 AAC the audio losses several decibels.
Anyone had the same problem and hopefully a solution to this?
Cheers,
Alex