======= squelch

squelch zeroes an incoming PCM signal to digital silence when sufficiently quiet for a sufficient time. This can be helpful when compressing a recorded signal using RLE, for example.

Signal comes in through stdin and the squelched signal is written to stdout.

Stream format is assumed to be raw 16-bit signed-integer PCM.

Compiling

make

Usage

some_program --producing --samples | squelch [OPTION]... | ...

Command line options

-u SAMPLES output buffer length, samples; defaults to 2048

-l LEVEL silence threshold, in absolute amplitude; defaults to 1024 (-30 dB)

-L LEVEL silence threshold, in dB; internally sets absolute amplitude; (e.g. -L -30)

-d SAMPLES duration of silence to trigger squelch, in samples; defaults to 4096

-t SAMPLES transition time, in samples; defaults to 512

If both level options are set, the latter wins.

Copying

Copyright (c) 2012-2013, Oona Räisänen [email protected]

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.