VU Meter

Here is the example of the plugin configuration for VU Meter functionality:

pcm_scope.peppyalsa {
        type peppyalsa
        decay_ms 400
        meter "/home/pi/myfifo"
        meter_max 100
        meter_show 0
}

• type - this parameter defines the name of the ALSA plugin. This is required parameter and it should always be peppyalsa
• decay_ms - this is optional parameter. It defines in milliseconds the time for changing signal from its minimum value (0) to its maximum value (32767). That affects the smoothness of the VU Meter. In most cases 400 should work fine.
• meter - this is optional parameter which can be used to define the named pipe name. If this parameter was not defined then the plugin will use the default name /home/pi/myfifo. If the named pipe with such name doesn't exist then the plugin will create one.
• meter_max - this is optional parameter. It will define the maximum value of the VU Meter signal. If parameter was not defined then the value will be changing from 0 to 32767.
• meter_show - this is optional parameter. If this parameter is 1 then VU Meter will be displayed in the terminal/window where playback was started. The VU Meter will be displayed using ASCII characters hence no graphical context (e.g. X-Windows) is required. That meter can be helpful for debugging purposes. Here is the example of the meter when parameter meter_show is 1:

The VU Meter will be visible only when there is a reader available on the other end of the named pipe.

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