app.py

import gradio as gr
import keras
import librosa
#import hopsworks
import os
import numpy as np
import shutil
from functions import log_mel_spectrogram, split_spectrogram, load_audio_file, image_transformer, save_spectrogram_as_png
from datasets import load_dataset

def return_input(input):
    return input

def create_image_folder(folder):
    try:
        os.mkdir(folder)
    except:
        FileExistsError()
    return

def delete_folder(folder):
    try:
        shutil.rmtree(folder)
    except:
        FileNotFoundError()
    return

 
def create_dataset(image_folder):
    image_dataset = load_dataset(image_folder, split=None)["train"]
    print(image_dataset)
    image_dataset = image_dataset.map(image_transformer, batched=True, fn_kwargs={"mode": "L"})
    
    image_dataset_tf = image_dataset.to_tf_dataset(batch_size=1, columns="image")
    
    return image_dataset_tf


def majority_vote(raw_predictions):
    label_predictions = np.argmax(raw_predictions, axis=1)
    labels, count = np.unique(label_predictions, return_counts=True)
    
    winner = labels[np.argmax(count)]
    return label_decoding[winner]

def predict(audio):
    create_image_folder(folder)
    try:
        audio_array = load_audio_file(audio, sample_rate, res_type, duration)
    except:
        return "Error when loading audio. Did you submit a file?"
    spectrogram = log_mel_spectrogram(audio_array, sample_rate, nfft, hop_length, window)
    spec_splits = split_spectrogram(spectrogram, output_shape)
    for idx, split in enumerate(spec_splits):
        save_path = os.path.join(folder, f"{idx+1}_spec.png")
        save_spectrogram_as_png(split, save_path, sample_rate, nfft, hop_length)
    
    image_dataset = create_dataset(folder)
    
    raw_preds = model.predict(image_dataset, verbose=0)
    
    genre_pred = majority_vote(raw_preds)
    return f"The submitted audio belongs to the {genre_pred} genre!"

sample_rate = 22050
res_type = "kaiser_fast"
nfft = 2048
hop_length = 512
window = "hann"
output_shape = (128, 256)
duration = 0
folder = "images"

label_decoding = {0: "Electronic",
                  1: "Experimental",
                  2: "Folk",
                  3: "Hip-Hop",
                  4: "Instrumental",
                  5: "International",
                  6: "Pop",
                  7: "Rock"}

model_path = "best_model.keras"
model = keras.models.load_model(model_path, compile=False)


"""
model_version = 1
project = hopsworks.login()
mr = project.get_model_registry()
model = mr.get_model("cnn_genre_classifier", version=model_version)

model_dir = model.download()

model = keras.models.load_model(model_dir)
"""



with gr.Blocks() as demo:
    with gr.Row():
        gr.Markdown(
    """
    # Music Genre Classifier
    
    Hello!
    
    This is a prototype for a genre classification service, where you can upload an audio file, 
    and the model will predict which genre it belongs to!
    
    The model has been trained to predict 8 top-level genres, that each encompasses a multitude of sub-genres.
    
    The top-level genres are:
    
    1. Electronic
    2. Experimental
    3. Folk
    4. Hip-Hop
    5. Intrumental
    6. International
    7. Pop
    8. Rock
    
    Upload your favorite song or choose one of the example tracks and give it a try!
    """
        )
    with gr.Row():
        with gr.Column():
            audio = gr.Audio(sources="upload", type="filepath", label="Upload your song here", format="wav")
        with gr.Column():
            files = gr.FileExplorer(label="Example songs", file_count="single", root="examples", interactive=True)
            files.change(fn=return_input, inputs=files, outputs=audio)
    with gr.Row():
        answer_box = gr.Text(label="Answer appears here", interactive=False)
    with gr.Row():
        submit_audio = gr.Button(value="Submit audio for prediction")
        submit_audio.click(fn=predict, inputs=audio, outputs=answer_box, trigger_mode="once")
        submit_audio.click(fn=delete_folder)


demo.launch(share=True)