[Asterisk-video] Audio stream shortenings with some mobile phones (using mp4save)

[Florian Greb]

Hello,
during my tests I discovered a serious problem using mp4save. 
With some mobile phones, audio data is far from being synchronous. The
worst test results we had were from a Motorola KRZR K3. A one minute
recording had audio already finished after 40 seconds, the video playing
all the 60 seconds. The bug is clearly on the receiving part, as the
files created had these defects.
The tests were done counting every some seconds alound in front of the
camera. Especially speaking pauses were shortened drastically! After
replacing the speak (which includes pauses between the numbers) by a
simple constant sinus tone the defects were gone. 
Mobile phones don't send audio data if there is only noise to transmit.
How is it handled? Maybe this is the place to look for the bug. 
Ideas, anybody?


Tested phones:
---------------
SonyEricsson P1	  - no shortenings
Nokia 6233 / 6234 - nearly no shortenings
Nokia 6680	  - small shortenings (1-2 sec. missing out of 60)
SonyEricsson K800i - substantial shortenings (~6 sec. missing out of 60)
Motorola KRZR K3 - huge shortenings (~20 sec. missing out of 60)

Kind regards,

Florian