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AMETER : An Alsa meter plugin for Linux audio software , with a graphical display .

http://laugeo.free.fr/ameter.html

This program aims at giving level metering capability to Alsa audio programs that does not have it, and that cannot use Jack/Meterbrige ( Glame is an example, as arecord/aplay or mplayer ).

It can be used also for OSS applications (using alsa-oss, aoss wrapper and a properly written .asoundrc).

It has an overload indicator, which can be resetted by pressing a key.

Laurent Georget <laugeo@free.fr>
(This plugin is heavily based on the level meter plugin from Abramo Bagnara <abramo@alsa-project.org> (originally with a ncurse display),
and on Meterbridge from Steve Harris ( http://plugin.org.uk/meterbridge/ ), for the SDL display code.)

Thanks to Andrew Burgess (http://www.cichlid.com) for fixing the aplay problem when interrupting with ctrl+c.

1. Requirements :
   • Alsa ( tested with 1.0.9)
   • SDL and SDL_image with PNG support: packages should come with your Linux distribution (tested with version 1.2 (may work with 1.0))
2. Compilation :

        ./configure
        make
        su -c "make install"

3) Edit (or create) .asoundrc file in your home directory to have the following lines :

pcm_scope.ameter {

type ameter
}
pcm_scope_type.ameter {

lib /usr/local/lib/libameter.so }
pcm.ameter {

        type meter
        slave.pcm 'hw:0,0'
        frequency 50
        scopes.0 ameter

}
pcm.dsp0 ameter

( The frequency parameter is the nb of update/sec , 50 is the default value)

4) Test :

        Using Glame: 
        - In audio preferences:
                - Set output plugin to alsa_audio_out 
                - Set output device to ameter
        (This is ok for playing and recording)

        Using aplay/arecord:
        aplay -D ameter sound.wav 
        arecord -D ameter soundrec.wav

        Using mplayer:
        mplayer -ao alsa:device=ameter /tmp/film.avi    

        Using alsa-oss:
        aoss realplay /usr/lib/RealPlayer8/firstrun.rm

5) Limitations :

• Only one stereo sound card