Book Image

Mastering FreeSWITCH

By : Russell Treleaven, Seven Du, Schreiber, Ken Rice, Mike Jerris, Florent Krieg, Kalyani Kulkarni, Charles Bujold
4 (1)
Book Image

Mastering FreeSWITCH

4 (1)
By: Russell Treleaven, Seven Du, Schreiber, Ken Rice, Mike Jerris, Florent Krieg, Kalyani Kulkarni, Charles Bujold

Overview of this book

FreeSWITCH is one of the best tools around if you’re looking for a modern method of managing communication protocols through a range of different media. From real-time browser communication with the WebRTC API to implementing VoIP (voice over internet protocol), with FreeSWITCH you’re in full control of your projects. This book shows you how to unlock its full potential – more than just a tutorial, it’s packed with plenty of tips and tricks to make it work for you. Written by members of the team who actually helped build FreeSWITCH, it will guide you through some of the newest features of version 1.6 including video transcoding and conferencing. Find out how FreeSWITCH interacts with other tools and APIs, learn how to tackle common (and not so common) challenges ranging from high availability to IVR development and programming advanced PBXs. Great communication functionality begins with FreeSWITCH – find out how and get your project up and running today.
Table of Contents (15 chapters)
7
7. WebRTC and Mod_Verto
14
Index

HD audio frontiers are pushed by cellphones, right now


We've just seen that for regular, traditional telephony, we only need an audio source that is mono, narrowband, 8 bit, 8 khz. That is considered good quality, toll-grade quality.

It compares well with cellular phones' quality, which in the last decade has drastically lowered our expectations. Cellular phones' codecs did not sound very good; actually they were much worse than G711 or G729. But we're on the verge of a revolution in the sound quality of telecommunication.

First it was Skype, who introduced us all to 16 khz, wideband audio. Ever tried to listen to music via Skype? It sounds good. And speech too: You immediately hear and feel, you're not on PSTN (and neither on cellphone).

But there is much more to come: 4G and LTE cellular networks are starting to become available everywhere, with audio in ultra-wideband and high definition (HD). The cellular network will once again change our expectations, but this time it will raise the bar...