app.py

import gradio as gr
import jax
import jax.numpy as jnp
import librosa
import dac_jax
from dac_jax.audio_utils import volume_norm, db2linear
import spaces
import tempfile
import os
import numpy as np

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

@spaces.GPU
def encode(audio_file_path):
    try:
        # Load audio with librosa, specifying duration
        signal, sample_rate = librosa.load(audio_file_path, sr=44100, mono=True, duration=5.0)  # Set duration as needed

        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
        x = model.preprocess(x, sample_rate)
        z, codes, latents, commitment_loss, codebook_loss = model.encode(x, train=False)

        # Save encoded data to a temporary file (using numpy.savez for now)
        with tempfile.NamedTemporaryFile(delete=False, suffix=".npz") as temp_file:
            np.savez(temp_file.name, z=z, codes=codes, latents=latents, input_db=input_db)

        return temp_file.name

    except Exception as e:
        gr.Warning(f"An error occurred during encoding: {e}")
        return None

@spaces.GPU
def decode(compressed_file_path):  # Changed input to compressed_file_path
    try:
        # Load encoded data directly from the file path
        data = np.load(compressed_file_path)  # No need for temporary files
        z = data['z']
        codes = data['codes']
        latents = data['latents']
        input_db = data['input_db']

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

        # Undo previous loudness normalization
        y = y * db2linear(input_db - (-16))  # Using -16 as the target_db

        decoded_audio = np.array(y).squeeze()
        return (44100, decoded_audio)

    except Exception as e:
        gr.Warning(f"An error occurred during decoding: {e}")
        return None

# Gradio interface
with gr.Blocks() as demo:
    gr.Markdown("<h1 style='text-align: center;'>Audio Compression with DAC-JAX</h1>")

    with gr.Tab("Encode"):
        with gr.Row():
            audio_input = gr.Audio(type="filepath", label="Input Audio")
            encode_button = gr.Button("Encode", variant="primary")
        with gr.Row():
            encoded_output = gr.File(label="Compressed Audio (.npz)")

        encode_button.click(encode, inputs=audio_input, outputs=encoded_output)

    with gr.Tab("Decode"):
        with gr.Row():
            compressed_input = gr.File(label="Compressed Audio (.npz)")
            decode_button = gr.Button("Decode", variant="primary")
        with gr.Row():
            decoded_output = gr.Audio(label="Decompressed Audio")

        decode_button.click(decode, inputs=compressed_input, outputs=decoded_output)

demo.queue().launch()