[linux-audio-dev] Merging digital sampling sessions

[Jonathan Woithe]

David Kastrup writes:

> On another note: it would seem like a simple enough task to let the
> recording start with the first non-zero sample. ... I'd also like to prune
> trailing zeros at some point of time.

Although it is not a native ALSA app (due mainly to me not having the time
to port it yet), batchrec does this.  It still works with ALSA through the
OSS emulation layer; adding native ALSA support is on my todo list for the
next few months.  You can grab it from

  http://www.physics.adelaide.edu.au/~jwoithe/batchrec-1.2.0.tgz

It's pretty raw (no configure script yet) but shouldn't be too hard to
compile on most systems.

Batchrec can be requested to wait for signal above a certain amplitude
before it records.  It will also stop recording after the same threshold has
been present for a user-specified time (if desired); at that point recording
will stop, the file will be closed and the program will then wait for signal
above the threshold again.  I've used it extensively with analog inputs
(hense the use of a threshold rather than exactly 0).  The only fly in the
ointment will be whether the SPDIF input on your soundcard can be mapped in
the OSS emulation layer in such a way that OSS applications can use it.

Regards
  jonathan