[gst-devel] comfort noise generation bin

pl bossart bossart.nospam at gmail.com
Tue Apr 27 01:49:21 CEST 2010


> Oops, I though rtpjitterbuffer would generate a lost packet message
> after a certain amount of time, but it seems to only generate it on the
> next packet after a gap. So you are right, it is not a good solution.

I am not sure if this is the same mechanism, but the g72xdepay
elements mark the first buffer after a talk burst as DISCONT as per
the RTP spec. However this is somewhat unusable for the decoder since
there are no indicators of the start of the silence part...

> I still think we need some kind of arbitration to not have more than one
> decoder produce silence since Farsight2 will keep the previous decoders
> if the sender starts sending on a new PT. That's why I wanted to do it
> as late as possible (in the mixer).

Comfort Noise is generated mainly so that the receiver doesn't think
the line is dead. Granted, if this is a multi-party call the need for
CNG is less important. Chances are someone will be talking.
Nevertheless, the decision to go to SID frames is made by each
transmitter, the receiver can't do much in terms of arbitration:
either you support CNG or you don't....
-Pierre




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