Configuring audio outputs
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## Configuring audio outputs

Audio outputs are devices which actually play the audio chunks produced by MPD. You can configure any number of audio output devices, but there must be at least one. If none is configured, MPD attempts to auto-detect. Usually, this works quite well with ALSA, OSS and on Mac OS X.

To configure an audio output manually, add one or more `audio_output` blocks to `mpd.conf`:

    audio_output {
        type "alsa"
        name "my ALSA device"
        device "hw:0"
    }

The following table lists the `audio_output` options valid for all plugins:

Name | Description
--- | ---
`type` | The name of the plugin.
`name` | The name of the audio output. It is visible to the client. Some plugins also use it internally, e.g. as a name registered in the PULSE server.
`format` | Always open the audio output with the specified audio format (`samplerate:bits:channels`), regardless of the format of the input file. This is optional for most plugins. Any of the three attributes may be an asterisk to specify that this attribute should not be enforced, example: `48000:16:*`. `*:*:*` is equal to not having a `format` specification. The following values are valid for `bits`: `8` (signed 8 bit integer samples), `16`, `24` (signed 24 bit integer samples padded to 32 bit), `32` (signed 32 bit integer samples), `f` (32 bit floating point, -1.0 to 1.0), "`dsd`" means DSD (Direct Stream Digital). For DSD, there are special cases such as "`dsd64`", which allows you to omit the sample rate (e.g. `dsd512:2` for stereo DSD512, i.e. 22.5792 MHz). The sample rate is special for DSD: MPD counts the number of bytes, not bits. Thus, a DSD "bit" rate of 22.5792 MHz (DSD512) is 2822400 from MPD's point of view (44100*512/8).
`enabled` `yes|no` | Specifies whether this audio output is enabled when MPD is started. By default, all audio outputs are enabled. This is just the default setting when there is no state file; with a state file, the previous state is restored.
`tags` `yes|no` | If set to `no`, then MPD will not send tags to this output. This is only useful for output plugins that can receive tags, for example the `httpd` output plugin.
`always_on` `yes|no` | If set to `yes`, then MPD attempts to keep this audio output always open. This may be useful for streaming servers, when you don't want to disconnect all listeners even when playback is accidentally stopped.
`mixer_type` `hardware|software|null|none` | Specifies which mixer should be used for this audio output: the hardware mixer (available for ALSA, OSS and PulseAudio), the software mixer, the "null" mixer (`null`; allows setting the volume, but with no effect; this can be used as a trick to implement an external mixer) or no mixer (`none`). By default, the hardware mixer is used for devices which support it, and none for the others.
`replay_gain_handler` `software|mixer|none` | Specifies how replay gain is applied. The default is `software`, which uses an internal software volume control. `mixer` uses the configured (hardware) mixer control. `none` disables replay gain on this audio output.

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