ml-ddsp

A collection of differentiable Max objects based on DDSP and DDSP PyTorch using LibTorch with min-devkit.

Structure

• min-package-template is a minimal template version of the Min-DevKit package to get started following current best-practices for package creation.
• min-api is a folder within the devkit containing all of the support files you will need to compile an external object written in modern C++. This folder you will include in your own package's source folder.
• min-lib contains building blocks, helper classes, and unit generators that may be useful in authoring C++ code for audio, video, and data processing.

Prerequisites

To build externals, you will need some form of compiler support on your system.

• On the Mac this means Xcode 10 or higher (you can get from the App Store for free).
• On Windows this means Visual Studio 2017 or 2019 (you can download a free version from Microsoft). The installer for Visual Studio 2017 offers an option to install Git, which you should choose to do.

You will also need to install a recent version of CMake (version 3.19 or higher).

Building

Note: this repository has only been built and tested on Mac x86_64 (Intel) and M1 using Rosetta. Pre-built binaries are available in the release section.

0. Clone the repository into Max's Packages folder. If you clone it elsewhere you will need to make an alias to it in your Packages folder. The Packages folder can be found inside of your Max 8 folder which is inside of your user's Documents folder. Make sure you clone recursively so that all sub-modules are properly initiated : git clone <your repository> --recursive
1. In the Terminal or Console app of your choice, change directories (cd) into the folder you cloned/installed in step 0.
2. Run mkdir build to create a folder with your various build files.
3. Run cd build to put yourself into that folder.
4. Now you can generate the projects for your chosen build environment:

Mac

only tested on Mac x86_64 (Intel) and M1 using Rosetta

5. Download LibTorch C++ (tested with the following version of LibTorch: Stable 1.12.0 > Mac > LibTorch > C++ > Default), and unzip to a known directory on your system. In case you encounter the "*.dylib cannot be opened because the developer cannot be verified" error, run xattr -d -r com.apple.quarantine . in the libtorch/lib folder.
6. In the build folder, run cmake -G Xcode -DCMAKE_PREFIX_PATH=path/to/libtorch .. with the absolute path to the libtorch folder you downloaded and unzipped in the previous step.
7. Next run cmake --build . or open the Xcode project from this build folder and use the GUI.

Note: you can add the -j4 option where "4" is the number of cores to use. This can help to speed up your builds, though sometimes the error output is interleaved in such a way as to make troubleshooting more difficult.

Windows

not tested yet

You can run cmake --help to get a list of the options available. Assuming some version of Visual Studio 2019, the commands to generate the projects will look like this:

cmake -G "Visual Studio 16 2019" ..

Or using Visual Studio 2017 it will look like this:

cmake -G "Visual Studio 15 2017 Win64" ..

Having generated the projects, you can now build by opening the .sln file in the build folder with the Visual Studio app (just double-click the .sln file) or you can build on the command line like this:

cmake --build . --config Release

Third-party Dependencies

Apart from LibTorch, there are further third-party Max packages to be installed in order to run the example patches:

• sigmund~ is used for pitch and loudness tracking, and can be retrieved here. Download and unzip in the Max Packages folder.
• hirt.convolver~ from the HISSTools Impulse Response Toolbox is used for convolution and parametric reverb and can be installed using the package manager within Max.

Overview

The package contains the following objects, which are all differentiable and can be trained end-to-end:

Autoencoder Objects

• ddsp.audio-decoder~, basic neural decoder that takes pitch and loudness, runs inference on a pre-trained model and outputs an audio signal
• ddsp.control-decoder~, multichannel neural decoder that takes pitch and loudness, runs inference on a pre-trained model and outputs control parameters for additive + subtractive synthesis, i.e. fundamental frequency, harmonic amplitudes and filter magnitudes
• ddsp.latent-decoder~, multichannel neural decoder that takes pitch and loudness, and latent parameters based on MFCCs, runs inference on a pre-trained model and outputs control parameters for additive + subtractive synthesis, i.e. fundamental frequency, harmonic amplitudes and filter magnitudes

Synthesis Objects

• ddsp.mc-harmonic-oscillator~, multichannel additive synthesizer that takes fundamental frequency and harmonic amplitudes and outputs harmonic signals
• ddsp.harmonic-oscillator~, additive synthesizer that takes fundamental frequency and harmonic amplitudes and outputs a mono audio signal
• ddsp.filtered-noise~, subtractive synthesizer that takes filter magnitudes and outputs a mono audio signal

Reverb

The hirt.convolver~ is used to convolve the output signal with learned impulse responses which can be further processed and altered (decay, size, pre-delay, gain, eq) within the tool.

Pre-trained Models

Download pre-trained models here: Download

Each model contains three files:

• model.ts, model in the torschscript file format, containing the architecture and weights of the neural network
• impulse.wav, learned impulse response for (de-)reverberation
• config.yaml, summary of all model parameters and additional configuration

The following models are currently available:

• cello
• doublebass
• flute
• saxophone
• trumpet
• violin
• synthetic (latent decoder only)
  • mallet
  • synth lead
  • vocal

Compatible versions of these models for the audio, control and latent decoder can be found in the respective subfolders:

• models/audio_decoder
• models/control_decoder
• models/latent_decoder

The acoustic models have been trained on monophonic recordings of acoustic instruments in the URMP dataset. The synthetic models have been trained on recordings of synthesized instruments in the NSynth dataset.

Example Patches

Example patches which use the differentiable Max objects are located in the patches/ folder. In order to load a model and perform inference, a load message has to be sent to the decoder object which opens the file browser to load a torchscript model (*.ts file). Make sure to load a model that has been trained on the according decoder architecture.

Note: the buffer size / signal vector size should not exceed the maximum of 1024. A buffer size between 128 and 512 has been found to work best.

• The audio_decoder_example.maxpat shows how to combine the basic ddsp.audio-decoder~ with reverb for parameter space exploration, timbre transfer and MIDI control.
• The control_decoder_example.maxpat shows how to combine the ddsp.control-decoder~, ddsp.mc-harmonic_oscillator~ and ddsp.filtered_noise~ multichannel objects with reverb for parameter space exploration, timbre transfer and MIDI control.
• The latent_decoder_example.maxpat shows how to combine the ddsp.latent-decoder~, ddsp.mc-harmonic_oscillator~ and ddsp.filtered_noise~ multichannel objects with reverb for parameter space and latent space exploration.

Training

currently in a separate repository

For training of custom models, follow the instructions in the training repository.

Unit Testing

On the command line you can run all unit tests using Cmake:

• on debug builds: ctest -C Debug .
• on release builds: ctest -C Release .

Or you can run an individual test, which is simply a command line program:

• cd ..
• cd tests
• mac example: ./test_dcblocker_tilde -s
• win example: test_dcblocker_tilde.exe -s

Or you can run them with your IDE's debugger by selecting the "RUN_TESTS" target.

Continuous Integration

Continuous Integration (CI) is a process by which each code check-in is verified by an automated build and automated tests to allow developers to detect problems early and distribute software easily.

The min-starter project models CI using Github Actions.

Additional Documentation

• Min Documentation Hub For guides, references, and resources
• Min Wiki For additional topics, advanced configuration, and user submissions
• How to Create a New Object
• How to Update the underlying Max API

Contributors / Acknowledgements

• See the GitHub Contributor Graph for the API

Support

For support, please use the developer forums at: http://cycling74.com/forums/