diff --git a/riffusion/audio.py b/riffusion/audio.py deleted file mode 100644 index 323e851..0000000 --- a/riffusion/audio.py +++ /dev/null @@ -1,213 +0,0 @@ -""" -Audio processing tools to convert between spectrogram images and waveforms. -""" -import io -import typing as T - -import numpy as np -from PIL import Image -import pydub -from scipy.io import wavfile -import torch -import torchaudio - - -def wav_bytes_from_spectrogram_image(image: Image.Image) -> T.Tuple[io.BytesIO, float]: - """ - Reconstruct a WAV audio clip from a spectrogram image. Also returns the duration in seconds. - """ - - max_volume = 50 - power_for_image = 0.25 - Sxx = spectrogram_from_image(image, max_volume=max_volume, power_for_image=power_for_image) - - sample_rate = 44100 # [Hz] - clip_duration_ms = 5000 # [ms] - - bins_per_image = 512 - n_mels = 512 - - # FFT parameters - window_duration_ms = 100 # [ms] - padded_duration_ms = 400 # [ms] - step_size_ms = 10 # [ms] - - # Derived parameters - num_samples = int(image.width / float(bins_per_image) * clip_duration_ms) * sample_rate - n_fft = int(padded_duration_ms / 1000.0 * sample_rate) - hop_length = int(step_size_ms / 1000.0 * sample_rate) - win_length = int(window_duration_ms / 1000.0 * sample_rate) - - samples = waveform_from_spectrogram( - Sxx=Sxx, - n_fft=n_fft, - hop_length=hop_length, - win_length=win_length, - num_samples=num_samples, - sample_rate=sample_rate, - mel_scale=True, - n_mels=n_mels, - max_mel_iters=200, - num_griffin_lim_iters=32, - ) - - wav_bytes = io.BytesIO() - wavfile.write(wav_bytes, sample_rate, samples.astype(np.int16)) - wav_bytes.seek(0) - - duration_s = float(len(samples)) / sample_rate - - return wav_bytes, duration_s - - -def spectrogram_from_image( - image: Image.Image, max_volume: float = 50, power_for_image: float = 0.25 -) -> np.ndarray: - """ - Compute a spectrogram magnitude array from a spectrogram image. - - TODO(hayk): Add image_from_spectrogram and call this out as the reverse. - """ - # Convert to a numpy array of floats - data = np.array(image).astype(np.float32) - - # Flip Y take a single channel - data = data[::-1, :, 0] - - # Invert - data = 255 - data - - # Rescale to max volume - data = data * max_volume / 255 - - # Reverse the power curve - data = np.power(data, 1 / power_for_image) - - return data - -def image_from_spectrogram( - spectrogram: np.ndarray, max_volume: float = 50, power_for_image: float = 0.25 -) -> Image.Image: - """ - Compute a spectrogram image from a spectrogram magnitude array. - """ - # Apply the power curve - data = np.power(spectrogram, power_for_image) - - # Rescale to 0-1 - data = data / np.max(data) - - # Rescale to 0-255 - data = data * 255 - - # Invert - data = 255 - data - - # Convert to a PIL image - image = Image.fromarray(data.astype(np.uint8)) - - # Flip Y - image = image.transpose(Image.FLIP_TOP_BOTTOM) - - # Convert to RGB - image = image.convert("RGB") - - return image - -def spectrogram_from_waveform( - waveform: np.ndarray, - sample_rate: int, - n_fft: int, - hop_length: int, - win_length: int, - mel_scale: bool = True, - n_mels: int = 512, -) -> np.ndarray: - """ - Compute a spectrogram from a waveform. - """ - - spectrogram_func = torchaudio.transforms.Spectrogram( - n_fft=n_fft, - power=None, - hop_length=hop_length, - win_length=win_length, - ) - - waveform_tensor = torch.from_numpy(waveform.astype(np.float32)).reshape(1, -1) - Sxx_complex = spectrogram_func(waveform_tensor).numpy()[0] - - Sxx_mag = np.abs(Sxx_complex) - - if mel_scale: - mel_scaler = torchaudio.transforms.MelScale( - n_mels=n_mels, - sample_rate=sample_rate, - f_min=0, - f_max=10000, - n_stft=n_fft // 2 + 1, - norm=None, - mel_scale="htk", - ) - - Sxx_mag = mel_scaler(torch.from_numpy(Sxx_mag)).numpy() - - return Sxx_mag - - -def waveform_from_spectrogram( - Sxx: np.ndarray, - n_fft: int, - hop_length: int, - win_length: int, - num_samples: int, - sample_rate: int, - mel_scale: bool = True, - n_mels: int = 512, - max_mel_iters: int = 200, - num_griffin_lim_iters: int = 32, - device: str = "cuda:0", -) -> np.ndarray: - """ - Reconstruct a waveform from a spectrogram. - - This is an approximate inverse of spectrogram_from_waveform, using the Griffin-Lim algorithm - to approximate the phase. - """ - Sxx_torch = torch.from_numpy(Sxx).to(device) - - # TODO(hayk): Make this a class that caches the two things - - if mel_scale: - mel_inv_scaler = torchaudio.transforms.InverseMelScale( - n_mels=n_mels, - sample_rate=sample_rate, - f_min=0, - f_max=10000, - n_stft=n_fft // 2 + 1, - norm=None, - mel_scale="htk", - max_iter=max_mel_iters, - ).to(device) - - Sxx_torch = mel_inv_scaler(Sxx_torch) - - griffin_lim = torchaudio.transforms.GriffinLim( - n_fft=n_fft, - win_length=win_length, - hop_length=hop_length, - power=1.0, - n_iter=num_griffin_lim_iters, - ).to(device) - - waveform = griffin_lim(Sxx_torch).cpu().numpy() - - return waveform - - -def mp3_bytes_from_wav_bytes(wav_bytes: io.BytesIO) -> io.BytesIO: - mp3_bytes = io.BytesIO() - sound = pydub.AudioSegment.from_wav(wav_bytes) - sound.export(mp3_bytes, format="mp3") - mp3_bytes.seek(0) - return mp3_bytes