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im_webapp/src/widgets/audio-recorder.jsx
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React

// Audio recorder widget.
import React from 'react';
import { defineMessages, injectIntl } from 'react-intl';
import AudioPlayer from './audio-player.jsx';
// Workaround for https://bugs.chromium.org/p/chromium/issues/detail?id=642012
// It adds duration and SeekHead to the webm record.
import fixWebmDuration from 'webm-duration-fix';
import { intArrayToBase64 } from '../lib/blob-helpers.js'
import { secondsToTime } from '../lib/strformat';
import { KEYPRESS_DELAY, MAX_DURATION, MIN_DURATION } from '../config.js';
// FFT resolution.
const BUFFER_SIZE = 256;
// Make canvas bigger than the element size to reduce blurring.
const CANVAS_UPSCALING = 2.0;
// Thickness of a visualization bar.
const LINE_WIDTH = 3 * CANVAS_UPSCALING;
// Spacing between two visualization bars.
const SPACING = 2 * CANVAS_UPSCALING;
// Duration represented by one visualization bar.
const MILLIS_PER_BAR = 100;
// Color of histogram bars
const BAR_COLOR = '#BBBD';
// Vertical scaling for visualization bars.
const BAR_SCALE = 64.0;
// Number of bars in preview.
const VISUALIZATION_BARS = 96;
// Maximum number of samples per bar.
const MAX_SAMPLES_PER_BAR = 10;
// Default recording format (FF, Chrome except on iOS).
const DEFAULT_AUDIO_MIME_TYPE = 'audio/webm';
// Safari supports only mp4 as audio recording format.
const SAFARI_AUDIO_MIME_TYPE = 'audio/mp4';
const AUDIO_MIME_TYPES = [DEFAULT_AUDIO_MIME_TYPE, SAFARI_AUDIO_MIME_TYPE, ''];
const messages = defineMessages({
icon_title_delete: {
id: 'icon_title_delete',
defaultMessage: 'Delete recording',
description: 'Icon tool tip for deleting recorded audio'
},
icon_title_pause: {
id: 'icon_title_pause',
defaultMessage: 'Pause playback',
description: 'Icon tool tip for pausing audio playback'
},
icon_title_resume: {
id: 'icon_title_resume',
defaultMessage: 'Resume playback',
description: 'Icon tool tip for resuming audio playback'
},
icon_title_send: {
id: 'icon_title_send',
defaultMessage: 'Send message',
description: 'Icon tool tip for sending a message'
},
failed_to_init_audio: {
id: 'failed_to_init_audio',
defaultMessage: 'Failed to initialize audio recording',
description: 'Error message when audio is not available'
}
});
class AudioRecorder extends React.PureComponent {
constructor(props) {
super(props);
this.state = {
enabled: true,
audioRecord: null,
recording: true,
paused: false,
duration: '0:00',
blobUrl: null,
preview: null
};
this.visualize = this.visualize.bind(this);
this.initMediaRecording = this.initMediaRecording.bind(this);
this.initCanvas = this.initCanvas.bind(this);
this.getRecording = this.getRecording.bind(this);
this.cleanUp = this.cleanUp.bind(this);
this.handleResume = this.handleResume.bind(this);
this.handlePause = this.handlePause.bind(this);
this.handleDelete = this.handleDelete.bind(this);
this.handleDone = this.handleDone.bind(this);
this.durationMillis = 0;
this.startedOn = null;
this.viewBuffer = [];
this.canvasRef = React.createRef();
// Timestamp for sending "recording" notifications.
this.recordingTimestamp = 0;
}
componentDidMount() {
this.stream = null;
this.mediaRecorder = null;
this.audioContext = null;
this.audioInput = null;
this.analyser = null;
this.audioChunks = [];
// Start recorder right away.
try {
navigator.mediaDevices.getUserMedia({audio: true, video: false}).then(this.initMediaRecording, this.props.onError);
} catch (err) {
this.props.onError(err);
}
}
componentWillUnmount() {
this.startedOn = null;
if (this.stream) {
this.cleanUp();
}
}
// Draw amplitude of sound.
visualize() {
this.initCanvas();
const pcmData = new Uint8Array(this.analyser.frequencyBinCount);
const width = this.canvasWidth;
const height = this.canvasHeight;
// Number of bars.
const viewLength = (width / (LINE_WIDTH + SPACING)) | 0;
// Duration of audio which fits onto the screen.
const viewDuration = MILLIS_PER_BAR * viewLength;
this.canvasContext.lineWidth = LINE_WIDTH;
this.canvasContext.strokeStyle = BAR_COLOR;
let prevBarCount = 0;
let volume = 0.0;
let countPerBar = 0;
const drawFrame = _ => {
if (!this.startedOn) {
return;
}
window.requestAnimationFrame(drawFrame);
const duration = this.durationMillis + (Date.now() - this.startedOn);
// Update record length timer.
this.setState({duration: secondsToTime(duration / 1000)});
// Check if record is too long.
if (duration > MAX_DURATION) {
this.startedOn = null;
this.mediaRecorder.pause();
this.durationMillis += Date.now() - this.startedOn;
this.setState({enabled: false, recording: false, duration: secondsToTime(this.durationMillis / 1000)});
}
// Draw histogram.
// Get current waveform and calculate its amplitude.
this.analyser.getByteTimeDomainData(pcmData);
let amp = 0.0;
for (const amplitude of pcmData) {
amp += (amplitude - 127) ** 2;
}
// Sum the amplitude.
volume += Math.sqrt(amp/pcmData.length);
countPerBar ++;
let barCount = (duration / MILLIS_PER_BAR) | 0;
// Shift of the histogram along x-axis to make scrolling smooth. No need to shift if recording is too short.
const dx = viewDuration > duration ? 0 :
(duration - MILLIS_PER_BAR * barCount) / MILLIS_PER_BAR * (LINE_WIDTH + SPACING);
if (prevBarCount != barCount) {
prevBarCount = barCount;
// Add new amplitude visualization bar.
this.viewBuffer.push(volume/countPerBar);
volume = 0.0;
countPerBar = 0;
if (this.viewBuffer.length > viewLength) {
// Keep at most 'viewLength' amplitude bars.
this.viewBuffer.shift();
}
}
// Clear canvas.
this.canvasContext.clearRect(0, 0, width, height);
// Draw amplitude bars.
this.canvasContext.beginPath();
for (let i = 0; i < this.viewBuffer.length; i++) {
let x = i * (LINE_WIDTH + SPACING) - dx;
let y = Math.max(Math.min(this.viewBuffer[i] / BAR_SCALE, 0.9) * height, 1);
this.canvasContext.moveTo(x, (height - y) * 0.5);
this.canvasContext.lineTo(x, (height + y) * 0.5);
}
// Actually draw the bars on canvas.
this.canvasContext.stroke();
// Send notification, if needed.
const now = new Date().getTime();
if (now - this.recordingTimestamp > KEYPRESS_DELAY) {
this.props.onRecordingProgress();
this.recordingTimestamp = now;
}
}
drawFrame();
}
handlePause(e) {
e.preventDefault();
this.mediaRecorder.pause();
this.mediaRecorder.requestData();
this.durationMillis += Date.now() - this.startedOn;
this.startedOn = null;
this.setState({recording: false});
}
handleResume(e) {
e.preventDefault();
if (this.state.enabled) {
this.startedOn = Date.now();
this.mediaRecorder.resume();
this.setState({recording: true}, this.visualize);
}
}
handleDelete(e) {
e.preventDefault();
this.durationMillis = 0;
this.startedOn = null;
this.mediaRecorder.stop();
this.cleanUp();
this.setState({recording: false});
}
handleDone(e) {
e.preventDefault();
this.setState({recording: false});
if (this.startedOn) {
this.durationMillis += Date.now() - this.startedOn;
this.startedOn = null;
}
// Stop recording and return data.
if (this.mediaRecorder) {
this.mediaRecorder.stop();
}
}
initCanvas() {
this.canvasRef.current.width = this.canvasRef.current.offsetWidth * CANVAS_UPSCALING;
this.canvasRef.current.height = this.canvasRef.current.offsetHeight * CANVAS_UPSCALING;
this.canvasContext = this.canvasRef.current.getContext('2d');
this.canvasContext.lineCap = 'round';
// To reduce line blurring.
this.canvasContext.translate(0.5, 0.5);
this.canvasWidth = this.canvasRef.current.width;
this.canvasHeight = this.canvasRef.current.height;
}
initMediaRecording(stream) {
this.stream = stream;
AUDIO_MIME_TYPES.some(mimeType => {
if (MediaRecorder.isTypeSupported(mimeType)) {
this.mediaRecorder = new MediaRecorder(stream, {mimeType: mimeType, audioBitsPerSecond: 24_000});
return true;
}
return false;
});
if (!this.mediaRecorder) {
console.warn('MediaRecorder failed to initialize: no supported audio formats');
this.props.onError(this.props.intl.formatMessage(messages.failed_to_init_audio));
return;
}
// The following code is needed for visualization.
this.audioContext = new AudioContext();
this.audioInput = this.audioContext.createMediaStreamSource(stream);
if (!this.audioInput) {
console.warn('createMediaStreamSource returned null: audio input unavailable');
this.props.onError(this.props.intl.formatMessage(messages.failed_to_init_audio));
return;
}
this.analyser = this.audioContext.createAnalyser();
this.analyser.fftSize = BUFFER_SIZE;
this.audioInput.connect(this.analyser);
this.mediaRecorder.onstop = _ => {
if (this.durationMillis > MIN_DURATION) {
this.getRecording(this.mediaRecorder.mimeType)
.then(result => this.props.onFinished(result.url, result.preview, this.durationMillis));
} else {
this.props.onDeleted();
}
this.cleanUp();
}
this.mediaRecorder.ondataavailable = (e) => {
if (e.data.size > 0) {
this.audioChunks.push(e.data);
}
if (this.mediaRecorder.state != 'inactive') {
this.getRecording(this.mediaRecorder.mimeType).then(result => {
this.setState({
blobUrl: result.url,
preview: result.preview
});
});
}
}
this.durationMillis = 0;
this.startedOn = Date.now();
this.mediaRecorder.start();
this.visualize();
this.props.onRecordingProgress();
this.recordingTimestamp = this.startedOn;
}
// Obtain data in a form sutable for sending or playing back.
getRecording(mimeType) {
mimeType = mimeType || DEFAULT_AUDIO_MIME_TYPE;
let blob = new Blob(this.audioChunks, {type: mimeType});
// If duration is valid, apply fix for Chrome's WebM duration bug.
const result = mimeType == DEFAULT_AUDIO_MIME_TYPE ?
fixWebmDuration(blob, mimeType) :
Promise.resolve(blob);
return result
.then(fixedBlob => { blob = fixedBlob; return fixedBlob.arrayBuffer(); })
.then(arrayBuff => this.audioContext.decodeAudioData(arrayBuff))
.then(decoded => this.createPreview(decoded))
.then(preview => ({url: window.URL.createObjectURL(blob), preview: intArrayToBase64(preview)}));
}
// Preview must be calculated at the source: Chrome does not allow background AudioContext.
createPreview(audio) {
const data = audio.getChannelData(0);
// Number of amplitude bars in preview.
const viewLength = Math.min(data.length, VISUALIZATION_BARS);
// The number of samples in each bar.
const totalSPB = (data.length / viewLength) | 0;
// Distance between samples: we are going to take just a fracton of samples.
const samplingRate = Math.max(1, (totalSPB / MAX_SAMPLES_PER_BAR) | 0);
let buffer = [];
let max = -1;
for (let i = 0; i < viewLength; i++) {
let amplitude = 0;
let count = 0;
for (let j = 0; j < totalSPB; j += samplingRate) {
amplitude += data[totalSPB * i + j] ** 2;
count ++;
}
const val = Math.sqrt(amplitude / count);
buffer.push(val);
max = Math.max(max, val);
}
// Normalize amplitude to 0..100.
if (max > 0) {
buffer = buffer.map(a => (100 * a / max) | 0);
}
return buffer;
}
cleanUp() {
if (this.audioInput) {
this.audioInput.disconnect();
}
this.stream.getTracks().forEach(track => track.stop());
}
render() {
const {formatMessage} = this.props.intl;
const resumeClass = 'material-icons ' + (this.state.enabled ? 'red' : 'gray');
return (
<div className="audio">
<a href="#" onClick={this.handleDelete} title={formatMessage(messages.icon_title_delete)}>
<i className="material-icons gray">delete_outline</i>
</a>
{this.state.recording ?
<canvas ref={this.canvasRef} />
:
<AudioPlayer
src={this.state.blobUrl}
preview={this.state.preview}
duration={this.durationMillis}
short={true} />
}
<div className="duration">{this.state.duration}</div>
{this.state.recording ?
<a href="#" onClick={this.handlePause} title={formatMessage(messages.icon_title_pause)}>
<i className="material-icons">pause_circle_outline</i>
</a> :
<a href="#" onClick={this.handleResume} title={formatMessage(messages.icon_title_resume)}>
<i className={resumeClass}>radio_button_checked</i>
</a>
}
<a href="#" onClick={this.handleDone} title={formatMessage(messages.icon_title_send)}>
<i className="material-icons">send</i>
</a>
</div>
);
}
}
export default injectIntl(AudioRecorder);