Asterisk: sip telephony at 16 kbps, how to compress voice?

Question

Asterisk

Good day.
There is a guaranteed speed with prioritization of sip traffic at 16kbps. But you can clearly talk "out of the box" with the 729th codec starting from 20kbps. Satellite channel, protocol - tcp, jitter 150ms. Tell me, poke into the link, somehow you can make the voice shrink to 16kbps in one direction?

Answer 1

disallow: all
allow: g729:60
traffic packetization decides. So it was possible to shrink the channel.

Answer 2

It will be difficult to find a solution. And is only sip or rtp/media prioritized too? Yes, and on the satellite jitter is already very insidious.