Control Names
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## Control Names

There are some standards to define the control names. A control is usually defined from the three parts as “SOURCE DIRECTION FUNCTION”.

The first, `SOURCE`, specifies the source of the control, and is a string such as “Master”, “PCM”, “CD” and “Line”. There are many pre-defined sources.

The second, `DIRECTION`, is one of the following strings according to the direction of the control: “Playback”, “Capture”, “Bypass Playback” and “Bypass Capture”. Or, it can be omitted, meaning both playback and capture directions.

The third, `FUNCTION`, is one of the following strings according to the function of the control: “Switch”, “Volume” and “Route”.

The example of control names are, thus, “Master Capture Switch” or “PCM Playback Volume”.

There are some exceptions:

### Global capture and playback

“Capture Source”, “Capture Switch” and “Capture Volume” are used for the global capture (input) source, switch and volume. Similarly, “Playback Switch” and “Playback Volume” are used for the global output gain switch and volume.

### Tone-controls

tone-control switch and volumes are specified like “Tone Control - XXX”, e.g. “Tone Control - Switch”, “Tone Control - Bass”, “Tone Control - Center”.

### 3D controls

3D-control switches and volumes are specified like “3D Control - XXX”, e.g. “3D Control - Switch”, “3D Control - Center”, “3D Control - Space”.

### Mic boost

Mic-boost switch is set as “Mic Boost” or “Mic Boost (6dB)”.

More precise information can be found in `Documentation/sound/alsa/ControlNames.txt`.

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