Driven by the development of WebRTC (web real time communication) using the OPUS codec, 3CX has adopted that codec so it can run on the 3CX PBX.
What exactly is OPUS?
Opus is a codec that can cover applications from low bandwidth up to CD quality. It is more efficient than almost every existing codec at every level, as shown in the graph below:
From the graph you can see the high-end comparison against music codecs such as MP3, AAC, and others. Opus is not just HD like wideband codecs such as G722, but rather full band or super-wideband. If G722 is comparable to HD television, Opus at the high end is like 4K / Ultra HD.
In terms of the latency Opus introduces, it is as good as or better than other codecs, yet it can be used in a wide range of applications, from VoIP through streaming and wireless speakers to long-distance music performance. Of course, it also needs to support stereo.
Attached is an image comparing Opus with other codecs:
Opus is an IETF standard, so there is no license and it is free. A major advantage of using Opus is that its mode, and its bit rate, can shift dynamically. For VoIP applications, this means it can adapt to changes in the network, either by operating at a bit rate suited to the available bandwidth or by adjusting if the available bandwidth changes, and it can also correct packet loss through forward error correction.
For Opus to be aware of network changes, RTCP must be enabled in both directions.
Consider these examples of Opus voice calls under various conditions:
Uncompressed speech (G711 at 64kb/s)
Narrowband Opus at 8kb/s
Wideband Opus at 16kb/s
Fullband Opus at 32kb/s
What about packet loss? Here is an example with 30% packet loss:
Super-wideband Opus at 24kbps with 30% packet loss
Super-wideband Opus at 24kbps with 30% packet loss but with forward error correction enabled
30% packet loss would make most VoIP calls impossible. Imagine the impact this could have on your PBX system.
Bit rate changing dynamically from narrowband 8kb/s to 64kb/s
So what are you waiting for? Switch to the Opus codec for better quality!
