DAC-JAX

Descript Audio Codec (.dac) is a high-fidelity general neural audio codec introduced in the paper
"High-Fidelity Audio Compression with Improved RVQGAN".

This repository is an unofficial JAX implementation of the PyTorch-based DAC and has no affiliation with Descript.

You can read the DAC-JAX paper here.

Usage

Installation

1. Install the CPU version of PyTorch. We strongly suggest the CPU version because trying to install a GPU version can conflict with JAX's CUDA-related installation.

2. Install audiotools with no dependencies, since we want to avoid PyTorch again.

   pip install --no-dependencies descript-audiotools

3. Install JAX (with GPU support).

4. Install DAC-JAX with one of the following:

   pip install git+https://github.com/DBraun/DAC-JAX
   

   Or,

   python -m pip install .

   Or, if you intend to contribute, clone and do an editable install:

   python -m pip install -e ".[dev]"

Weights

The original Descript repository releases model weights under the MIT license. These weights are for models that natively support 16 kHz, 24kHz, and 44.1kHz sampling rates. Our scripts download these PyTorch weights and load them into JAX. Weights are automatically downloaded when you first run an encode or decode command. You can download them in advance with one of the following commands:

python -m dac_jax download_model # downloads the default 44kHz variant
python -m dac_jax download_model --model_type 44khz --model_bitrate 16kbps # downloads the 44kHz 16 kbps variant
python -m dac_jax download_model --model_type 44khz # downloads the 44kHz variant
python -m dac_jax download_model --model_type 24khz # downloads the 24kHz variant
python -m dac_jax download_model --model_type 16khz # downloads the 16kHz variant

The default download location is ~/.cache/dac_jax. You can change the location by setting an absolute path value for an environment variable DAC_JAX_CACHE. For example, on macOS/Linux:

export DAC_JAX_CACHE=/Users/admin/my-project/dac_jax_models

If you do this, remember to still have DAC_JAX_CACHE set before you use the load_model function.

Compress audio

python -m dac_jax encode /path/to/input --output /path/to/output/codes

This command will create .dac files with the same name as the input files. It will also preserve the directory structure relative to input root and re-create it in the output directory. Please use python -m dac_jax encode --help for more options.

Reconstruct audio from compressed codes

python -m dac_jax decode /path/to/output/codes --output /path/to/reconstructed_input

This command will create .wav files with the same name as the input files. It will also preserve the directory structure relative to input root and re-create it in the output directory. Please use python -m dac_jax decode --help for more options.

Programmatic usage

Here we use DAC-JAX as a "bound" module, freeing us from repeatedly passing variables as an argument and using .apply. Note that bound modules are not meant to be used in fine-tuning.

import dac_jax
from dac_jax.audio_utils import volume_norm, db2linear

import jax.numpy as jnp
import librosa

# Download a model and bind variables to it.
model, variables = dac_jax.load_model(model_type="44khz")
model = model.bind(variables)

# Load a mono audio file
signal, sample_rate = librosa.load('input.wav', sr=44100, mono=True, duration=.5)

signal = jnp.array(signal, dtype=jnp.float32)
while signal.ndim < 3:
    signal = jnp.expand_dims(signal, axis=0)

target_db = -16  # Normalize audio to -16 dB
x, input_db = volume_norm(signal, target_db, sample_rate)

# Encode audio signal as one long file (may run out of GPU memory on long files)
x = model.preprocess(x, sample_rate)
z, codes, latents, commitment_loss, codebook_loss = model.encode(x, train=False)

# Decode audio signal
y = model.decode(z, length=signal.shape[-1])

# Undo previous loudness normalization
y = y * db2linear(input_db - target_db)

# Calculate mean-square error of reconstruction in time-domain
mse = jnp.square(y-signal).mean()

Compression with constant GPU memory regardless of input length:

import dac_jax

import jax
import jax.numpy as jnp
import librosa

# Download a model and set padding to False because we will use the JIT-functions.
model, variables = dac_jax.load_model(model_type="44khz", padding=False)

# Load a mono audio file
signal, sample_rate = librosa.load('input.wav', sr=44100, mono=True, duration=.5)

signal = jnp.array(signal, dtype=jnp.float32)
while signal.ndim < 3:
    signal = jnp.expand_dims(signal, axis=0)

# Jit-compile these functions because they're used inside a loop over chunks.
@jax.jit
def compress_chunk(x):
    return model.apply(variables, x, method='compress_chunk')

@jax.jit
def decompress_chunk(c):
    return model.apply(variables, c, method='decompress_chunk')

win_duration = 0.5  # Adjust based on your GPU's memory size
dac_file = model.compress(compress_chunk, signal, sample_rate, win_duration=win_duration)

# Save and load to and from disk
dac_file.save("compressed.dac")
dac_file = dac_jax.DACFile.load("compressed.dac")

# Decompress it back to audio
y = model.decompress(decompress_chunk, dac_file)

Training

The baseline model configuration can be trained using the following commands.

python scripts/train.py --args.load conf/base.yml

In root directory, monitor with Tensorboard (runs will appear next to scripts):

tensorboard --logdir ./runs

Testing

python -m pytest tests

Limitations

Pull requests—especially ones which address any of the limitations below—are welcome.

• PyTorch is required as a dependency because it's used to load model weights before converting to JAX. As long as this is required, we recommend installing the CPU version of PyTorch.
• We hope to remove audiotools as a dependency since it's a PyTorch library.
• We implement the "chunked" compress/decompress methods from the PyTorch repository, although this technique has some problems outlined here.
• We have not performed a full training run, although we have tested the train scripts, loss functions and eval metrics.
• If you want to perform a training run—especially one which reproduces the original paper—you should examine any "todo" in train.py or in the config files.
• We have not run all evaluation scripts in the scripts directory.
• The model architecture code (model/dac.py) has many static methods to help with finding DAC's delay and output_length. Please help us refactor this so that code is not so duplicated and at risk of typos.
• In audio_utils.py we use DM_AUX's STFT function instead of jax.scipy.signal.stft.
• The source code of DAC-JAX has several todo: markings which indicate (mostly minor) improvements we'd like to have.
• We don't have a Docker image yet like the original DAC repository does.
• Please check the limitations of argbind.

Citation

If you use DAC-JAX in your work, please cite the original DAC:

@article{kumar2024high,
  title={High-fidelity audio compression with improved rvqgan},
  author={Kumar, Rithesh and Seetharaman, Prem and Luebs, Alejandro and Kumar, Ishaan and Kumar, Kundan},
  journal={Advances in Neural Information Processing Systems},
  volume={36},
  year={2024}
}

and DAC-JAX:

@misc{braun2024dacjax,
  title={{DAC-JAX}: A {JAX} Implementation of the Descript Audio Codec}, 
  author={David Braun},
  year={2024},
  eprint={2405.11554},
  archivePrefix={arXiv},
  primaryClass={cs.SD}
}