[linux-audio-dev] console JACK metering using ecasignalview

[Kai Vehmanen]

Hi,

yesterday I released ecasound-2.2.0-pre4 (approaching 
next stable release, yay!), which has a few JACK-specific
improvements:

- new command-line syntax for specifying inputs and 
  outputs, see:
  http://www.wakkanet.fi/~kaiv/ecasound/Documentation/users_guide/html_uguide/users_guide.html#SECTION00860000000000000000
- uses the new alsa_pcm:capture_x + playback_X syntax
  (requires JACK 0.40 or newer ==> CVS!)

You can find the package at:

  http://ecasound.seul.org/download/ecasound-2.2.0-pre4.tar.gz

And now to the main point: 2.2.0-pre4 comes with an updated
version of ecasignalview. Combined with the new JACK syntax,
ecasignalview now suits quite well for monitoring JACK-clients.
The basic syntax is:

ecasignalview -b:XXX -f:32,YYY,ZZZ jack_auto,foo_client null

... where:
	XXX = buffersize (jackd's -p:XXX)
	YYY = number of channels you want to monitor
	ZZZ = sample rate (jackd's -r:ZZZ)
	foo_client = any JACK client which uses out_X 
                     style port names

The meters are drawn with ncurses, while values are queried
through the ECI API (ie. ecasignalview is only linked 
against libc and libstdc++, not for instance against
libjack). The output looks like:

  http://eca.cx/screenshots/ecasound-2.2.0-pre4_ecasignalview.png

... there are a few known bugs, but in general it works
quite well. While not really a huge challenge for Steve's 
meterbridge ;), should be of interest to some of you.

-- 
 http://www.eca.cx
 Audio software for Linux!