h264 Audio sync issues.

Ok so I found some weird behaviour related to h264 embedded audio decode between different apps.

Apps I have tried:

Davinci Resolve
Autodesk Flame
Avid Pro Tools
Logic Pro
FCPX
(I do not have adobe software)

There seems to be a case, and I cant yet point my finger on when/why it happens that certain apps decode the embedded audio with a slight offset, sometimes its 1 frame sometimes its like half a frame off.

Here are my testfiles:
https://replayboys.fromsmash.com/soudnsyncTEST

What I found:
-> they are all sync in Pro Tools and Logic and FCPX
-> In Resolve all are sync except for the h264 created by Flame
-> in Flame they are all sync except for the h264 created by FFMPEG.

I am thinking it has to do with the "duration" metadata as thats what seems to differ between the different h264s?

https://developer.apple.com/library/arc ... ppenG.html

It might be due to this. thats my best guess.