app.py

import gradio as gr
import numpy as np
import plotly
import plotly.graph_objects as go
from plotly import tools
import scipy.signal as ssig
import librosa


def plot_stft(audio_file):

    # Load audio file
    audio, sampling_rate = librosa.load(audio_file)

    # Compute stft
    freq, frames, stft = ssig.stft(audio,
                                   sampling_rate,
                                   window='hann',
                                   nperseg=512,
                                   noverlap=412,
                                   nfft=1024,
                                   return_onesided=True,
                                   boundary='zeros',
                                   padded=True,
                                   axis=- 1)


    spectrogram = go.Heatmap(z=librosa.amplitude_to_db(np.abs(stft), ref=np.max),
                                     x=frames,
                                     y=freq,
                                     colorscale='Viridis')



    fig = go.Figure(spectrogram)


    fig.update_layout(
        #width=300,
        #height=500,
        font=dict(family='Latin Modern Roman', size=18),
        xaxis=dict(
            title='Time (seconds)',
            titlefont=dict(family='Latin Modern Roman',
                           size=18)),
        yaxis=dict(
            title='Frequency (Hz)',
            titlefont=dict(family='Latin Modern Roman',
                           size=18)),
        margin=dict(l=0, r=0, t=0, b=0),
        paper_bgcolor='rgba(0,0,0,0)',
        plot_bgcolor='rgba(0,0,0,0)')

    fig.update_traces(colorbar_thickness=8, selector=dict(type='heatmap'))
    fig.update_traces(showscale=True, showlegend=False, visible = True)
    fig.update_xaxes(visible=True, showgrid=False)
    fig.update_yaxes(visible=True, showgrid=False)
    plotly.offline.plot(fig, filename='stft.html', config={'displaylogo': False, 'modeBarButtonsToRemove': ['toImage','zoomIn', 'zoomOut','resetScale']})

    html_code = "<iframe data-src='stft.html' </iframe>"

    return html_code

# Gradio interface
demo = gr.Interface(fn=plot_stft, 
                    inputs=gr.Audio(type="filepath"), 
                    outputs="html")

demo.launch()