dtmfdecode -- decodes DTMF tones from A-law audio data
The dtmfdecode utility is part of the isdn4bsd package and is used to
detect DTMF tones in the audio stream.
It reads audio G.711 A-Law coded data from stdin and outputs the detected
numbers values as ASCII characters to stdout.
The detector is implemented as 8 narrow band-pass filters realized with
an integer double-cross recursive algorithm. Various ad-hoc methods are
employed to provide hysteresis and anti-bounce for the detected signals.
dtmfdecode < beep.al
will print a "1" to stdout.
ITU Recommendations G.711
The dtmfdecode utility was written by Poul-Henning Kamp
<phk@FreeBSD.org>. This man page was written by Hellmuth Michaelis
FreeBSD 5.2.1 February 15, 1999 FreeBSD 5.2.1 [ Back ]