VST plugin to author tmpsnd tracks in a DAW, written in C++ using Juce and libwebsockets

The VST, when loaded, creates a WebSocket server on port 7681. It waits for configuration data, sent by the web browser. Then it creates a bunch of sliders, that are VST parameters, that can be automated. When it receives incoming MIDI events or parameter change events, it sends that to the WebSocket, using the following text protocol:

• Parameter change: time,index,value:
  • time is the time where the event happened in seconds (floating point)
  • index is the index of the parameter (integer)
  • value is the new value of the parameter (float).
• Note On: time,index,note,velocity:
  • time is the time where the event happened in seconds (floating point)
  • index is the index of the instrument, which is equal to the midi channel where the note was sent from (integer)
  • note the MIDI note for this event
  • velocity the MIDI velocity for this event
• Note Off: time,index
  • time is the time where the event happened in seconds (floating point)
  • index is the index of the instrument, which is equal to the midi channel where the note was sent from (integer)

The first thing that you need to do when the VST in inserted on a track is to open up your web page that contains you synth. It should connect to a websocket on the machine that runs the DAW (or localhost of course), on port 7681.

Then the web browser should send a JSON-formatted string to tell the VST what are the parameter for this synth. The format goes like this, say, to define a snare drum, with two parameters, noise and pitch, two sends, delay and reverb, with parameters, and a master channel bus effect where you have a compressor with settable ratio:

{
  "snare": {
    "noise": {
      "min": 0.0,
      "max": 2.0,
      "step": 0.1,
      "default": 0.8
    },
    "pitch": {
      "min": 200.0,
      "max": 1000.0,
      "step": 1.0,
      "default": 400.0
    }
  },
  "sends": {
    "reverb": {
      "decay": {
        "min": 0.0,
        "max": 20.0,
        "step": 0.1,
        "default":5.0
      }
    },
    "delay": {
      "feedback": {
        "min": 0.0,
        "max": 150.0,
        "step": 1.0,
        "default":30.0
      }
    }
  },
  "master": {
    "compression": {
      "ratio": {
        "min": 0.0,
        "max": 20.0,
        "step": 0.1,
        "default":4.0
      }
    }
  }
};

This will create VST parameters for each parameter of each instruments, and a parameter for each send for each instrument (to control the send gain). Then it will create parameters for the send effects parameters and the master bus effects parameters.

Parameters are normal VST parameters, they can be automated and everything.

Get a copy of the VST SDK 2.4 from steinberg. Put it in ~/SDKs/vstsdk2.4 (C:\SDKs\vstsdk2.4 on Windows). I can't redistribute it here. You might or might not have to create an account at Steinberg.

The DLL for libwebsockets and its associated header files are included in this repo for convenience. Just open Builds\VisualStudio2015\tmpsnd-daw.sln in Visual Studio 2015 Community Edition (that is free for open source work), and press F5. You'll find the DLL in Builds\VisualStudio2015\Debug or Builds\VisualStudio2015\Release, depending on if you did a debug or release build in Visual Studio.

Install libwebsockets. For example, on Debian/Ubuntu, run sudo apt-get install libwebsockets. Then, cd Builds/Linux/, and make. That gives you a .so file that you can load in a DAW in Builds/Linux/build.

Install libwebsockets. The version in brew is fine: brew install libwebsockets.

Open the XCode project that is at Builds/MacOSX/tmpsnd-daw.xcodeproj, and build that. That gives you a thing that is called tmpsnd-daw.component in Builds/MacOSX/build/Debug/. You can load that in your DAW.

When loaded in a DAW, you can simply attach a debugger to the DAW (or the bridge process of the DAW), and debug from there. I recommend using the Audio Plugin Host from the Juce library, that is very lightweight, open source, and runnable in gdb/lldb/rr/valgrind easily.

The code in Source/ has been written by the authors of this project and is licensed under the terms of the new BSD license.