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+### The `midi` backend
+
+The MIDI backend provides read-write access to the MIDI protocol via virtual ports.
+
+#### Global configuration
+
+| Option	| Example value		| Default value 	| Description		|
+|---------------|-----------------------|-----------------------|-----------------------|
+| `name`	| `MIDIMonster`		| none			| MIDI client name	|
+
+#### Instance configuration
+
+| Option	| Example value		| Default value 	| Description		|
+|---------------|-----------------------|-----------------------|-----------------------|
+| `read`	| `20:0`		| none			| MIDI device to connect for input |
+| `write`	| `DeviceName`		| none			| MIDI device to connect for output |
+
+MIDI device names may either be `client:port` portnames or prefixes of MIDI device names.
+Run `aconnect -i` to list input ports and `aconnect -o` to list output ports.
+
+Each instance also provides a virtual port, so MIDI devices can also be connected with `aconnect <sender> <receiver>`.
+
+#### Channel specification
+
+The MIDI backend supports multiple channel types
+
+* `cc` - Control Changes
+* `note` - Note On/Off messages
+* `nrpn` - NRPNs (not yet implemented)
+
+A channel is specified using the syntax `channel<channel>.<type><index>`. The shorthand `ch` may be used instead
+of `channel`.
+The earlier syntax of `<type><channel>.<index>` is officially deprecated but still supported for compatability
+reasons. This support may be removed at some future time.
+
+Channels range from `0` to `15`. Each channel consists of 128 notes (numbered `0` through `127`) and 128 CC's
+(numbered likewise), a channel pressure control (also called 'channel aftertouch') and a pitch control.
+Each Note also has an additional pressure value associated with it.
+
+Example mappings:
+```
+midi1.ch0.note9 > midi2.channel1.cc4
+midi1.channel15.cc1 > midi1.channel0.note0
+```
+#### Known bugs / problems
+
+Currently, no Note Off messages are sent (instead, Note On messages with a velocity of 0 are
+generated, which amount to the same thing according to the spec). This may be implemented as
+a configuration option at a later time.
+
+NRPNs are not yet fully implemented, though rudimentary support is in the codebase.
+
+To see which events your MIDI devices output, ALSA provides the `aseqdump` utility. You can
+list all incoming events using `aseqdump -p <portname>`.
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