As part of lab-project (roaming PBX), I’ve compiled SILK and AMR codecs for Asterisk. AMR by googling and researching and SILK following instructions in this repository: https://github.com/mordak/codec_silk.
Update (20 March, 2013)
Tested SILK8 (SILK-NB) on Android (with CSIPSimple and Bria) – it does not work well, quality is not fantastic definitaly. Have tried both versions: compiled by myself and official Digium SILK codec.
Update #2 (21 March, 2013)
SILK8 are okay with Bria @ android, I had to modify codecs.conf and put following code:
[silk8] type=silk samprate=8000 fec=true packetloss_percentage=10 maxbitrate=20000 ; Default value was 10000 dtx=false ; Encode using discontinuous transmission mode or not. Turning this ; on will save bandwidth during periods of silence at the cost of ; increased computational complexity. Off by default.
Have little issues with AMR-NB, will post update later.
Update #2 (15 April, 2013)
AMR-NB works way better, I will try to describe installation steps in a separate post. Quality is amazing and bandwidth it consuming is so little. Unfortunately due to licensing issues it can’t be included as a part of official Asterisk distribution.