meters.lv2 is a collection of audio-level meters with GUI in LV2 plugin format.

It includes needle style meters (mono and stereo variants)

• IEC 60268-10 Type I / DIN
• IEC 60268-10 Type I / Nordic
• IEC 60268-10 Type IIa / BBC
• IEC 60268-10 Type IIb / EBU
• IEC 60268-17 / VU

Stereo & Mono variants of bar-graph meters:

• 30 Band 1/3 octave spectrum analyzer IEC 61260
• Digital True-Peak Meter (4x Oversampling), Type II rise-time, 13.3dB/s falloff.
• True-Peak (4x Oversampling) + RMS (600ms integration time) combined with numeric readout
• K-12, K-14, K-20 / RMS type K-Meters according to the K-system introduced by Bob Katz
• DR14 (pleasurizemusic.com, specs by tischmeyer/algorithmix)

and the following stereo plugins:

• EBU R128 Meter with Histogram and History
• Stereo Phase Correlation Meter (Needle Display)
• BBC Mid/Side M-6 (Needle Display)
• Goniometer (Stereo Phase Scope)
• Phase/Frequency Wheel
• Stereo/Frequency Monitor

as well as a mono:

• Signal Distribution Histogram

Currently all plugins come in both Gtk and openGL variants (both versions are installed in parallel).

Should be pretty much self-explanatory. A few notes:

• click + drag on the calibration-screw allows to modify the reference level of the needle meters
• shift + click on the calibration-screw resets to default
• ctrl + click on meters with scalable GUI resets the window-size to 100%
• clicking anywhere on the bar-graph meters resets the peak-hold

Compiling these plugin requires the LV2 SDK, gnu-make, a c-compiler, gtk+2.0, libpango, libcairo and openGL (sometimes called: glu, glx, mesa).

  git clone git://github.com/x42/meters.lv2.git
  cd meters.lv2
  make submodules
  make
  sudo make install PREFIX=/usr
  
  # test run
  jalv.gtk 'http://gareus.org/oss/lv2/meters#DINmono_gtk'

Note to packagers: The Makefile honors PREFIX and DESTDIR variables as well as CFLAGS, LDFLAGS and OPTIMIZATIONS (additions to CFLAGS).

These plugins count on rather recent (Jan 2013) fixes^Wfeatures of some libraries (but may work with older versions too):

In particular multi-threading in cairo, pixman and pango. Versions of those libraries earlier than libcairo < 1.12.10, libpixman < 0.30.2 and libpango < 1.32.6 are not thread-safe. As with all concurrency issues, things may or may not work and if you only open one meter GUI at a time it's usually fine.

Also note that the plugins use the LV2 idle-interface (lv2 >= 1.4.2) The plugin-host (eg. ardour or qtractor) needs to be compiled with this or a later version of the LV2 SDK to support the features.

The plugin-host must also support http://lv2plug.in/ns/ext/resize-port/

At the time of writing Ardour 3.4 and jalv.gtk do fulfill these criteria.