Support for Octet Align
Zoren Dela Cruz
Hello,
I am setting up a VoIP-to-VoLTE call using the MicroSIP softphone. MicroSIP advertises support for AMR and AMR-WB codecs in octet-aligned mode.
Could you please clarify how octet alignment should be enabled on RTPengine? Specifically, is octet alignment controlled by RTPengine configuration, or is it determined by the codec negotiation with the VoLTE device?
Thank you,
Zoren
Richard Fuchs
I am setting up a VoIP-to-VoLTE call using the MicroSIP softphone. MicroSIP advertises support for AMR and AMR-WB codecs in octet-aligned mode.
Could you please clarify how octet alignment should be enabled on RTPengine? Specifically, is octet alignment controlled by RTPengine configuration, or is it determined by the codec negotiation with the VoLTE device?
The details depend on the exact scenario you're working with, but in general there is no need to "enable" octet aligned mode.
For a normal call, codec negotiation happens between end devices, and rtpengine is not involved in the decision making process.
If you instruct rtpengine to transcode from/to AMR, then it depends on whether you're offering or accepting AMR.
If you're accepting an AMR offer from an end device, then the mode (octet aligned or bandwidth efficient) is mandated by the end device, and rtpengine will accept whichever mode was offered. If both are offered, then the first one listed will be accepted, but there are ways to tell rtpengine to prefer one over the other, or even reject one or both.
If you're instructing rtpengine to offer AMR to some end device, then the offer flags determine which mode will be offered. The default is octet aligned, but bandwidth efficient can be used instead, or even both can be offered. If the mode being offered is not supported by the end device, then AMR would likely be rejected.
Cheers