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beat-link-trigger

project chat Beat Link

An application to trigger MIDI events when CDJs start playing tracks, play certain kinds of phrases, reach particular beats, or whatever else you can think of. Built using beat-link.

”It's a shame Pioneer doesn't support this project, even unofficially. It's such a huge value add for them. When I was looking to buy my XDJ-XZ, lots of people were trying to sell me nice Denon gear but I'm locked into Pioneer because of BLT despite Denon being just as good if not a little better feature-wise.“

Nicholas Maddix on the project Gitter channel (where we discussed the project before we moved to the Zulip stream).

There is more description and a video in a DJ TechTools article, too!

But the most important thing you need to read, after skimming the introduction below, is the 📓 user guide.

License

💥 Warning: This may not yet work with the new CDJ-3000s. We have started making the changes required to work with more than four players, and we don't know what else might be needed. If you can do any testing with this new hardware, please share status reports and (even more important) open issues with log files, packet captures, and track analysis files if you run into problems!

Usage

Download the latest disk image (.dmg) installer for the Mac, .msi installer for 64-bit Windows, or executable .jar file for other platforms, from the releases page. Double-click an installed native app bundle to run it. If that doesn't work, or if you are using the executable .jar file, see below.

jar

A trigger window will open, in which you can choose the players you want to watch, the kind of MIDI message to send when they start and stop, and when the triggers are enabled:

Trigger window

There is also an interface for monitoring the status of each player found on the network, which you can access by choosing Show Player Status in the Network menu:

Player Status window

And starting with version 0.5.0, there is a Show interface with which you can paint cues on track beat grids, to automate away the complexities of manually managing triggers.

Show interface snippet

Going Further

This page is just a quick introduction! Please see the the full 📓 user guide for many more details, including:

  • How to configure Triggers
  • How to use Expressions
  • Working with title/artist metadata
  • Working with Ableton Link
  • Integration examples

And much more... and hopefully you will soon be coming up with interesting integration projects of your own.

You can also find user-contributed examples and resources on the project Wiki. Once you have come up with your own great ways to use Beat Link Trigger, please add a page or two the Wiki to share them with others!

Contributing

First of all, we would love to hear from you! We have no way of knowing who has discovered, explored, downloaded and tried Beat Link Trigger. So if you have, please write a quick note on the Zulip stream to let us know! Even if it is only to explain why it didn’t quite work for you.

If you run into specific problems or have ideas of ways Beat Link Trigger could be better, you can also open an Issue.

And if you think you've come up with new or better way to do something, terrific! Please take a look at our guidelines for contributing and we can't wait to hear from you!

Please be mindful of our Code of Conduct to make sure everyone feels welcome in the community.

Funding

Beat Link Trigger is, and will remain, completely free and open-source. If it has helped you, taught you something, or pleased you, let us know and share some of your discoveries and code as described above. If you’d like to financially support its ongoing development, you are welcome (but by no means obligated) to donate to offset the hundreds of hours of research, development, and writing that have already been invested. Or perhaps to facilitate future efforts, tools, toys, and time to explore.

Donate using Liberapay using Liberapay, or Donate using PayPal

If enough people jump on board, we may even be able to get a newer CDJ to experiment with, although that’s an unlikely stretch goal. 😀

Compatibility

This is in no way a sanctioned implementation of the protocols. It should be clear, but:

⚠️ Use at your own risk! For example, there are reports that the XDJ-RX (and XDJ-RX2) crash when BLT starts, so don’t use it with one on your network. As Pioneer themselves explain, the XDJ-RX does not actually implement the protocol:

“The LINK on the RX [and RX2] is ONLY for linking to rekordbox on your computer or a router with WiFi to connect rekordbox mobile. It can not exchange LINK data with other CDJs or DJMs.”

While these techniques appear to work for us so far, there are many gaps in our knowledge, and things could change at any time with new releases of hardware or even firmware updates from Pioneer.

You should also not expect to be able to run Beat Link Trigger, or any project like it, on the same machine that you are running rekordbox, because they will compete over access to network ports. Also, as noted above, the XDJ-RX and XDJ-RX2 do not support the full DJ Link protocol, and so will not work with software like this. And, of course, controllers which don't even have Link (Ethernet) jacks can't work either.

😒 Pre-Nexus gear (hardware older than the CDJ-900 nexus) is missing many important features, so BLT's capabilities are very degraded when working with such gear: much less information is available, we can't infer playback position/time code, and the hardware completely lacks tempo Sync or Master capabilities, so beat-based triggers are impossible, as is synchronization with Ableton Link. You can see what tracks are loaded, and whether the player is playing, but little more.

Beat Link Trigger seems to work great with Nexus gear and DJ-Link hardware released after that. It has been reported to work well with XDJ-1000 gear, and (starting with version 0.6.0) with the XDJ-XZ as well. If you can try it with anything else, please let us know what you learn in the Zulip stream, or if you have worked out actionable details about something that could be improved, open an Issue or submit a pull request so we can all improve our understanding together.

If something isn’t working with your hardware and you don’t yet know the details why, but are willing to learn a little and help figure it out, look at the dysentery project, which is where we are organizing the research tools and results which made programs like Beat Link Trigger possible.

Startup Issues

If you downloaded the .jar version and are using a recent Java distribution, double-clicking doesn’t open up the application, so open a terminal window and run it from the command line:

java -jar beat-link-trigger.jar

If that does not work, at least you will be able to see a detailed report of what went wrong, which can help you troubleshoot the issue.

Make sure you have a current OpenJDK distribution installed (we build releases with Amazon Corretto 11).

Font-Related Bugs

If you see a long exception stack trace similar to the one in this discussion and you have your computer language set to one that uses an alphabet which is substantially different from English, you may be encountering what seems to be a bug in the GUI library (or maybe even in Java itself). Try setting your system language to US English, and see if that at least lets you run the program.

Mac Trust Confirmation

If you are on a Mac, your best option nowadays is to download the disk image installer. It contains Beat Link Trigger packaged as a native Mac application, with an embedded Java runtime, so you don’t need to worry about installing or managing Java if you don’t use it for other purposes. It is code-signed and notarized by Deep Symmetry, so your Mac should be happy to install and run it without complaint.

Installer window

If you already have your own Java runtime installed and want to use it, you can instead download the smaller executable .jar file, but then the first time you try to launch the downloaded jar file by double-clicking it you will see an error like this because it is not a Mac-specific application:

Unsigned jar

You can fix that by control-clicking on the Jar and choosing “Open” at the top of the contextual menu that pops up. You will be asked to confirm that you really want to run it. Click the “Open” button in that confirmation dialog, and from then on, you will be able to run that copy by just double-clicking it.

Confirmation dialog

You will need to repeat this process for each version that you download. Also, current versions of OpenJDK no longer support launching Jar files by double-clicking, so you are better off switching to a native installer, or running via the command-line.

Licenses

Deep Symmetry

Copyright © 2016–2021 Deep Symmetry, LLC

Distributed under the Eclipse Public License 2.0. By using this software in any fashion, you are agreeing to be bound by the terms of this license. You must not remove this notice, or any other, from this software.

Library Licenses

Remote Tea

Used for communicating with the NFSv2 servers on players, licensed under the GNU Library General Public License, version 2.

The Kaitai Struct Java runtime

Used for parsing rekordbox exports and media analysis files, licensed under the MIT License.

RSyntaxtTextArea

Used for editing Clojure expression code.

Copyright © 2019, Robert Futrell. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  • Neither the name of the author nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

RSTAUI

Provides find/replace and other extended features to RSyntaxTextArea when editing Clojure expression code.

Copyright © 2012, Robert Futrell. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  • Neither the name of the author nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

inspector-jay

Supports inspection of the atoms that store local and global values for trigger and show expressions.

Copyright © 2013-2015 Tim Molderez All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the inspector-jay developer team nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE INSPECTOR-JAY DEVELOPER TEAM BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

radiance

Provides the cool dark look-and-feel for the graphical user interface.

Copyright © 2005-2019, Kirill Grouchnikov. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

  • Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Carabiner

The included copies of Carabiner are distributed under the GNU General Public License, version 2. A copy of the license can be found in gpl-2.0.md within this project.

Antora

Used to build the user guide, for embedding inside the application, and hosting on Netlify. Antora is licensed under the Mozilla Public License Version 2.0 (MPL-2.0).