Module a.speech

The SpeechChannel and higher level speech processing functions.

The SpeechChannel is a full duplex prosody channel with speech processing functions like play, record, digits or tone.

Internally, all speech processing functions in this module are represented as jobs. A job starts an audio operation, monitors it while it is running, and notifies the Controller when it is finished. Also, a job can stop its operation.

For simple applications, jobs may be ignored, but they are a useful building block for IVR-type applications. For an example, look at am/am.py. This is an an answering machine that implements its user interaction as a queue of jobs.

Function	guess_filetype	Guess format, sampling rate and data rate from the file extension.
Class	PlayJobBase	An Abstract Base Class for jobs that play PCM data.
Class	PlayJob	Job to play a file.
Class	SilenceJob	Job to play silence.
Class	RecordJob	Job to record a file.
Class	DigitsJob	Job to play a string of DTMF digits.
Class	ToneJob	Job to play a predefined Tone.
Class	DCReadJob	A DataComms receive job - experimental
Class	SpeechChannel	A full duplex Prosody channel.
Class	Conference	A Conference: seriously incomplete.
Class	Glue	Glue logic to tie a SpeechChannel to a Call.