Cannot play mp4 2 track audio files

[rumred85 0]

When I attempt to play my mp4 files in MBT I can play and encoded file with acc faac stereo.  I cannot play an encoded file with just ac3 passthrough.  I also cannot play an encoded file with acc faac stereo on the first track and ac3 passthrough on the second track.  The files are identical except for the audio. Now here is where it gets interesting, If i encode acc 5.1 on the first track and ac3 passthrough on the second track I can play the file, if i switch to ac3 passthrough (the second track) the file keeps playing without audio.

 

So here is my question, is there a problem with playing ac3 in MBT.  That is fine if there is BUT, all of my mp4's are encoded stereo on the first track (for compatibility) and ac3 passthrough on the second track (for devices that can handle 5.1).  I have never encoutered a device that will not play the file (MBC, Roku, Apple TV, Chromecast. WP8, Android, iphone, even MB in IE).  So in order to play my mp4's in MBT i will have to reencode acc5.1 and ac3 passthrough which would be a big pain.  Are you aware of this and is this something you may fix?

 

As a side note the 2 track file plays fine in MBC and media browser MB for windows 8.  I have also tried the MBT release and Dev versions and I am using LAV splitter .61.2.  Any idea as to what is going on?

Edited May 25, 2014 by rumred85