Spectrogram Drawer

Spectrogram drawer for heart, lung and bowel sounds

Install the NPM Module

npm i @stethio/spectrogram-drawer --save

Usage

1. Import AudioEngine

import AudioEngine from '@stethio/spectrogram-drawer';

2. Add Canvas to View:

    <canvas id="canvasID"></canvas>

3. Initialize:

    this.audioEngine = await new AudioEngine().initAudioEngine('canvasID', 'YOUR_SDK_KEY');
    let constraints = { audio: true }
    navigator.mediaDevices.getUserMedia(constraints)
      .then(async (stream) => {
        this.audioContext = new AudioContext();
        await this.audioEngine.startIt(false);
        this.audioEngine.loadOpusDecoder();
      })

Config:

• mode: 'HEART' | 'LUNG'
• gain for HEART: minimum 1 to maximum 3
• gain for LUNG: minimum 1 to maximum 20

4. Send Audio input

Load Audio files

    const audioContext = new AudioContext();
    fetch('audio.wav')
    .then(response => response.arrayBuffer())
    .then(arrayBuffer => audioContext.decodeAudioData(arrayBuffer))
    .then(audioBuffer => {
        this.audioEngine.testAudioInput(audioBuffer.getChannelData(0));
    });

Live input stream with getUserMedia.

    navigator.mediaDevices.getUserMedia({audio: true})
        .then((stream) => {
          const context = new AudioContext({sampleRate: 16000});
            const source = context.createMediaStreamSource(stream);
            const processor = context.createScriptProcessor(1024, 1, 1);
        
            source.connect(processor);
            processor.connect(context.destination);
        
            processor.onaudioprocess = (e) => {
              this.audioEngine.testAudioInput(e.inputBuffer.getChannelData(0));
            };
        });

Properties

1. Pause

this.audioEngine.pause();

2. Stop

this.audioEngine.stop();

3. Resume

this.audioEngine.resume();

4. Change Playback Speed

this.audioEngine.playbackSpeedChange(speed); // speed [0.25, 0.5, 0.75, 1, 1.25, 1.50, 1.75, 2]

5. Disable Auto Gain and Noise Filters

this.audioEngine.setAutoGainFlag(false); // By default, the gain is enabled
this.audioEngine.setFilterFlag(false); // By default, the filter is enabled

NOTE: We are supporting 5 canvases to be displayed at the same time in a screen