mel_module.py

from typing import Optional
from config import config
import numpy as np
import librosa
from PIL import Image 
import soundfile as sf

import warnings
warnings.filterwarnings("ignore", category=UserWarning, module='librosa')

class Mel:
    def __init__(
            self,
            file_path: str = None,
            spectrogram: Optional[np.ndarray] = None,
            image: Image.Image = None,
            x_res: int = config.image_size,
            y_res: int = config.image_size,
            sample_rate: int = config.sample_rate,
            n_fft: int = 2048,
            hop_length: int = 882,
            top_db: int = 80,
            n_iter: int = 32,
            ):
        self.hop_length = hop_length
        self.sr = sample_rate
        self.n_fft = n_fft
        self.top_db = top_db
        self.n_iter = n_iter
        self.x_res = x_res
        self.y_res = y_res
        self.n_mels = self.y_res
        self.slice_size = self.x_res * self.hop_length - 1
        self.file_path = file_path
        self.spectrogram = spectrogram
        self.image = image

        if file_path is not None and not isinstance(file_path, str):
            raise ValueError("file_path must be a string")
        if spectrogram is not None and not isinstance(spectrogram, np.ndarray):
            raise ValueError("spectrogram must be an ndarray")
        if image is not None and not isinstance(image, Image.Image):
            raise ValueError("image must be a PIL Image")

        if file_path is not None:
            self.load_file()
        elif image is not None:
            self.load_spectrogram()
        elif spectrogram is not None:
            self.load_image()
        else:
            print("Both file path and image are None!")

    def load_file(self):
        try:
            # Load audio
            if ".wav" in self.file_path:
                audio, _ = librosa.load(self.file_path, mono=True, sr=self.sr)
            # Pad audio if necessary
            if len(audio) < self.x_res * self.hop_length:
                audio = np.concatenate([audio, np.zeros((self.x_res * self.hop_length - len(audio),))])
            # Compute mel spectrogram
            S = librosa.feature.melspectrogram(
                y=audio, sr=self.sr, n_fft=self.n_fft, hop_length=self.hop_length, n_mels=self.n_mels, fmax=self.sr//2
            )
            log_S = librosa.power_to_db(S, ref=np.max, top_db=self.top_db)
            log_S = log_S[:self.y_res, :self.x_res]  # Ensure the spectrogram is of the desired size
            self.spectrogram = (((log_S + self.top_db) * 255 / self.top_db).clip(0, 255) + 0.5).astype(np.uint8)
            self.image = Image.fromarray(self.spectrogram)
        except Exception as e:
            print(f"Error loading {self.file_path}: {e}")

    def load_spectrogram(self):
        self.spectrogram = np.array(self.image)

    def load_image(self):
        self.spectrogram = self.spectrogram.astype("uint8")
        self.image = Image.fromarray(self.spectrogram)

    def get_spectrogram(self):
        return self.spectrogram

    def get_image(self):
        return self.image

    def get_audio(self):
        log_S = self.spectrogram.astype("float") * self.top_db / 255 - self.top_db
        S = librosa.db_to_power(log_S)
        audio = librosa.feature.inverse.mel_to_audio(
            S, sr=self.sr, n_fft=self.n_fft, hop_length=self.hop_length, n_iter=self.n_iter
        )
        return Audio(audio, rate=self.sr)

    def save_audio(self):
        audio = self.get_audio()
        sf.write(config.generated_track_path, audio.data, audio.rate)
        print(f"Audio saved to {config.generated_track_path}")

    def plot_spectrogram(self):
        plt.figure(figsize=(10, 4))
        plt.imshow(self.spectrogram, aspect='auto', origin='lower', cmap='viridis')
        plt.colorbar(label='Magnitude')
        plt.title('Mel Spectrogram')
        plt.xlabel('Time (frames)')
        plt.ylabel('Frequency (Mel bins)')
        plt.tight_layout()
        plt.show()