@gph wrote:
Saratoga,
Thanks for the quick reply. To your comments I offer my replies.
Unsurprising, since all modern AAC files use that container.
The 13 aac files I tested were created in iTunes as it turns out and not by MAX, as MAX produces files with a different container signature as my previous post outlined. MAX does not use that mp42 MP4 v2 container.
Regardless of whatever that tool you’re using reports, all of these files are in ISO 14496-14 as that is the MP4 container required for AAC. If it was otherwise they wouldn’t work in iTunes either 
Most likely that tool is just reading ftyp atom out of the file, which basically is just the encoders way of saying what it was trying to make and can take almost any value. I would not read too much into it.
If you follow the complete thread, you’ll see that the 13 aac files I used for my tests were created as aac files in iTunes and not by MAX,
Are you certain they’re plain iTunes files? Above you did not mention using iTunes to create those files, and also said that your library is a mixture of iTunes, MAX and downloaded files. Not saying you made a mistake, but if files don’t work I’d suspect theres something special about them.
