An audiobuffer of a given duration will return the same number of frames
regardless of how many channels it has.

Fix bug #29818.
Note: non-conference mode has been tested and works.
Conference mode may works, but some issues have been detected.

pjsip api has changed between pjproject-android and pjproject-2.1

This was causing invalid memory access and breaking getVolume()

* #29866: debugging log