Audio, audio, audio… If you're in telephony, you know what telephony is all about. End users' experience is determined by the quality of the sounds they are hearing, and, no matter how perfect the signaling and routing, their satisfaction will come from way down in the abstraction layers: their ears.
Creating and manipulating audio files and streams, for prompts, error messages, voicemails, call recordings, quality monitoring, and to entertain while waiting on the phone, is a sizeable part of any VoIP implementation.
FreeSWITCH gives us a lot of functions and primitives to deal with audio files and associate chores, and we'll see what the best practices are in this area, from how to combine audio fragments into meaningful phrases to how to stream live radio as music on hold.
In this chapter, we will cover:
Audio in VoIP, traditional and HD
FreeSWITCH audio formats, MP3, streaming
Music on Hold (MOH)
Recording and playing...