AAC-ADTS supports changing the number of audio channels on the fly
I have a mkv file that contains only one track.
It's an audio track encoded in AAC-adts. This audio track has 2 channels for the first 5 secondes. Then it has 6 channels for 5 seconds. Then 2, etc...
When playing it with vlc-1.1.4, it fails when switching from 2 audio channels to 6 audio channels with the following errors:
main error: incompatible audio channels count with layout mask
main error: failed to create audio output
But it correctly deteced 5.1 so I think the problem is not from the decoder but from the audio renderer that should be able to reconfigure itself on the fly.