Support MIDI tempo input/output

[RJ Skerry-Ryan]

would be nice if we could emit a MIDI clock signal so that SooperLooper and Ableton could sync to the Mixxx clock

[Be (be.ing)]

A very cool possibility for this, which I just saw two DJs use live with Traktor, is syncing multiple musicians' computers by connecting their audio interfaces with a MIDI cable.

[naught101 (naught101)]

More useful than that: I want to be able to use sequencers and synths live, and mix them back in via the line-in on my mixer. Being able to keep the sequencer in time with the playing track would be killer.

[Daniel Schürmann (daschuer)]

How is your sequencer connected to the PC?
If I remember right, emitting the master clock is half way implemented. The remaining issue was how to interface a device. Maybe we can use your use case to implement a solution.

[Hermann Zahnweh (1-ubuntuone-apriori)]

One use-case were MIDI beat clock output would be useful is support for the Roland DJ series controllers. These incorporate a step-based drum machine and emit and respond to beat clock signals.

The use-case would probably entail selecting (in the GUI or via a device-mapped control) which one of the decks to emit the clock signal for.

[Hermann Zahnweh (1-ubuntuone-apriori)]

Related GH issue: https://github.com/Lykos153/mixxx/issues/2

[Be (be.ing)]

The underlying code should be written in a generic way that will allow for reusing it to support Ableton Link (Bug #1625050).

[Jan Holthuis (holthuis-jan)]

The Roland DJ-505 would profit from this, since that could allow proper syncing with the built-in TR-S drum machine. (Mapping PR: https://github.com/mixxxdj/mixxx/pull/2111)

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/5682