Why are you using 96/96 inerleaving values with AVImux? You should try the defaults of 500/75. AVImux's interleave values do not need tweaked like we used to do in NanDub.
--------------------- -Matt 2003 DSG Ford Mustang Mach 1 MAC ProChamber, Flowmaster 40 Series Mufflers JLT Ram Air Intake, MGW Orange Handle Short Shifter