Transcoding in Telecom Business
Transcoding in telecom business is the process of converting media stream from one codec to another. This is performed in order to bridge differences in capabilities between the telecommunications systems supporting the caller and the called parties.
There are some scenarios when such kind of transcoding in telecom business is very useful. For example, when the two endpoint devices in a call and do not share a common codec among their codec sets. For example, if termination part only supports G.723 codec and origination end support G.729 codec then the call can stop audio from working in a direction if the VoIP provider is not Transcoding between the codecs.
In the SIP world, a commonplace to perform transcoding is the Session Border Controller (SBC). However, not all SBCs support transcoding, so it is important to pay attention to which ones do and which ones do not.
Transcoding and SBC
An SBC or Session Border Controller is a dedicated network element that helps to control real-time communication sessions over SIP-based VoIP infrastructures. SBC not only offers full control of the sessions but also conceals the internal network from outside. While SBC is available in both hardware and software forms, here the focus is on the software version.
REVE SBC has a built-in capability to handle various codecs and to do automatic transcoding in telecom business when necessary. It supports transcoding from or to the most popular codecs used in IP telecommunication like G729, G711, AMR etc.
Finally, it is important to consider what you want to transcode to and from. There are plenty of codecs out there (G.711, G.722, G.723.1, G.726, iLBC, AMR-wb, etc.) and not every SBC will transcode to and from every codec. It is not enough to ask if an SBC supports transcoding. You need to determine the list of codecs it works with.