app.py

import os
import torch
import shutil
import librosa
import warnings
import numpy as np
import gradio as gr
import librosa.display
import matplotlib.pyplot as plt
from collections import Counter
from model import EvalNet
from utils import get_modelist, find_files, embed_img


TRANSLATE = {
    "vibrato": "chan yin",
    "upward_portamento": "shang hua yin",
    "downward_portamento": "xia hua yin",
    "returning_portamento": "hui hua yin",
    "glissando": "gua zou, hua zhi",
    "tremolo": "yao zhi",
    "harmonics": "fan yin",
    "plucks": "gou, da, mo, tuo, ...",
}
CLASSES = list(TRANSLATE.keys())
TEMP_DIR = "./__pycache__/tmp"
SAMPLE_RATE = 44100


def circular_padding(spec: np.ndarray, end: int):
    size = len(spec)
    if end <= size:
        return spec

    num_padding = end - size
    num_repeat = num_padding // size + int(num_padding % size != 0)
    padding = np.tile(spec, num_repeat)
    return np.concatenate((spec, padding))[:end]


def wav2mel(audio_path: str, width=3):
    y, sr = librosa.load(audio_path, sr=SAMPLE_RATE)
    total_frames = len(y)
    if total_frames % (width * sr) != 0:
        count = total_frames // (width * sr) + 1
        y = circular_padding(y, count * width * sr)

    mel_spec = librosa.feature.melspectrogram(y=y, sr=sr)
    log_mel_spec = librosa.power_to_db(mel_spec, ref=np.max)
    dur = librosa.get_duration(y=y, sr=sr)
    total_frames = log_mel_spec.shape[1]
    step = int(width * total_frames / dur)
    count = int(total_frames / step)
    begin = int(0.5 * (total_frames - count * step))
    end = begin + step * count
    for i in range(begin, end, step):
        librosa.display.specshow(log_mel_spec[:, i : i + step])
        plt.axis("off")
        plt.savefig(
            f"{TEMP_DIR}/{i}.jpg",
            bbox_inches="tight",
            pad_inches=0.0,
        )
        plt.close()


def wav2cqt(audio_path: str, width=3):
    y, sr = librosa.load(audio_path, sr=SAMPLE_RATE)
    total_frames = len(y)
    if total_frames % (width * sr) != 0:
        count = total_frames // (width * sr) + 1
        y = circular_padding(y, count * width * sr)

    cqt_spec = librosa.cqt(y=y, sr=sr)
    log_cqt_spec = librosa.power_to_db(np.abs(cqt_spec) ** 2, ref=np.max)
    dur = librosa.get_duration(y=y, sr=sr)
    total_frames = log_cqt_spec.shape[1]
    step = int(width * total_frames / dur)
    count = int(total_frames / step)
    begin = int(0.5 * (total_frames - count * step))
    end = begin + step * count
    for i in range(begin, end, step):
        librosa.display.specshow(log_cqt_spec[:, i : i + step])
        plt.axis("off")
        plt.savefig(
            f"{TEMP_DIR}/{i}.jpg",
            bbox_inches="tight",
            pad_inches=0.0,
        )
        plt.close()


def wav2chroma(audio_path: str, width=3):
    y, sr = librosa.load(audio_path, sr=SAMPLE_RATE)
    total_frames = len(y)
    if total_frames % (width * sr) != 0:
        count = total_frames // (width * sr) + 1
        y = circular_padding(y, count * width * sr)

    chroma_spec = librosa.feature.chroma_stft(y=y, sr=sr)
    log_chroma_spec = librosa.power_to_db(np.abs(chroma_spec) ** 2, ref=np.max)
    dur = librosa.get_duration(y=y, sr=sr)
    total_frames = log_chroma_spec.shape[1]
    step = int(width * total_frames / dur)
    count = int(total_frames / step)
    begin = int(0.5 * (total_frames - count * step))
    end = begin + step * count
    for i in range(begin, end, step):
        librosa.display.specshow(log_chroma_spec[:, i : i + step])
        plt.axis("off")
        plt.savefig(
            f"{TEMP_DIR}/{i}.jpg",
            bbox_inches="tight",
            pad_inches=0.0,
        )
        plt.close()


def most_frequent_value(lst: list):
    counter = Counter(lst)
    max_count = max(counter.values())
    for element, count in counter.items():
        if count == max_count:
            return element

    return None


def infer(wav_path: str, log_name: str, folder_path=TEMP_DIR):
    if os.path.exists(folder_path):
        shutil.rmtree(folder_path)

    if not wav_path:
        return None, "Please input an audio!"

    spec = log_name.split("_")[-3]
    os.makedirs(folder_path, exist_ok=True)
    try:
        model = EvalNet(log_name, len(TRANSLATE)).model
        eval("wav2%s" % spec)(wav_path)

    except Exception as e:
        return None, f"{e}"

    jpgs = find_files(folder_path, ".jpg")
    preds = []
    for jpg in jpgs:
        input = embed_img(jpg)
        output: torch.Tensor = model(input)
        preds.append(torch.max(output.data, 1)[1])

    pred_id = most_frequent_value(preds)
    return (
        os.path.basename(wav_path),
        f"{TRANSLATE[CLASSES[pred_id]]} ({CLASSES[pred_id].capitalize()})",
    )


if __name__ == "__main__":
    warnings.filterwarnings("ignore")
    models = get_modelist(assign_model="vit_l_16_mel")
    examples = []
    example_wavs = find_files()
    for wav in example_wavs:
        examples.append([wav, models[0]])

    with gr.Blocks() as demo:
        gr.Interface(
            fn=infer,
            inputs=[
                gr.Audio(label="Upload a recording", type="filepath"),
                gr.Dropdown(choices=models, label="Select a model", value=models[0]),
            ],
            outputs=[
                gr.Textbox(label="Audio filename", show_copy_button=True),
                gr.Textbox(
                    label="Guzheng playing tech recognition",
                    show_copy_button=True,
                ),
            ],
            examples=examples,
            cache_examples=False,
            flagging_mode="never",
            title="It is recommended to keep the recording length around 3s.",
        )

        gr.Markdown(
            """
# Cite
```bibtex
@article{Zhou-2025,
  author  = {Monan Zhou and Shenyang Xu and Zhaorui Liu and Zhaowen Wang and Feng Yu and Wei Li and Baoqiang Han},
  journal = {Trans. Int. Society for Music Information Retrieval},
  volume  = {8},
  number  = {1},
  pages   = {22--38},
  year    = {2025},
  title   = {CCMusic: An Open and Diverse Database for Chinese Music Information Retrieval Research}
}
```"""
        )

    demo.launch()