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import React = require("react");
import axios from "axios";
import { action, computed, reaction, IReactionDisposer } from "mobx";
import { observer } from "mobx-react";
import Waveform from "react-audio-waveform";
import { Doc } from "../../fields/Doc";
import { List } from "../../fields/List";
import { listSpec } from "../../fields/Schema";
import { Cast, NumCast } from "../../fields/Types";
import { numberRange } from "../../Utils";
import "./AudioWaveform.scss";
import { Colors } from "./global/globalEnums";
export interface AudioWaveformProps {
duration: number; // length of media clip
rawDuration: number; // length of underlying media data
mediaPath: string;
layoutDoc: Doc;
clipStart: number;
clipEnd: number;
zoomFactor: number;
PanelHeight: () => number;
}
@observer
export class AudioWaveform extends React.Component<AudioWaveformProps> {
public static NUMBER_OF_BUCKETS = 100;
_disposer: IReactionDisposer | undefined;
@computed get waveHeight() { return Math.max(50, this.props.PanelHeight()); }
@computed get clipStart() { return this.props.clipStart; }
@computed get clipEnd() { return this.props.clipEnd; }
@computed get zoomFactor() { return this.props.zoomFactor; }
@computed get audioBuckets() { return Cast(this.props.layoutDoc[this.audioBucketField(this.clipStart, this.clipEnd, this.zoomFactor)], listSpec("number"), []); }
audioBucketField = (start: number, end: number, zoomFactor: number) => "audioBuckets/" + "/" + start.toFixed(2).replace(".", "_") + "/" + end.toFixed(2).replace(".", "_") + "/" + (zoomFactor * 10);
componentWillUnmount() {
this._disposer?.();
}
componentDidMount() {
this._disposer = reaction(() => ({ clipStart: this.clipStart, clipEnd: this.clipEnd, fieldKey: this.audioBucketField(this.clipStart, this.clipEnd, this.zoomFactor), zoomFactor: this.props.zoomFactor }),
({ clipStart, clipEnd, fieldKey, zoomFactor }) => {
if (!this.props.layoutDoc[fieldKey]) {
// setting these values here serves as a "lock" to prevent multiple attempts to create the waveform at nerly the same time.
const waveform = Cast(this.props.layoutDoc[this.audioBucketField(0, this.props.rawDuration, 1)], listSpec("number"));
this.props.layoutDoc[fieldKey] = waveform && new List<number>(waveform.slice(clipStart / this.props.rawDuration * waveform.length, clipEnd / this.props.rawDuration * waveform.length));
setTimeout(() => this.createWaveformBuckets(fieldKey, clipStart, clipEnd, zoomFactor));
}
}, { fireImmediately: true });
}
// decodes the audio file into peaks for generating the waveform
createWaveformBuckets = async (fieldKey: string, clipStart: number, clipEnd: number, zoomFactor: number) => {
axios({ url: this.props.mediaPath, responseType: "arraybuffer" }).then(
(response) => {
const context = new window.AudioContext();
context.decodeAudioData(
response.data,
action((buffer) => {
const rawDecodedAudioData = buffer.getChannelData(0);
const startInd = clipStart / this.props.rawDuration;
const endInd = clipEnd / this.props.rawDuration;
const decodedAudioData = rawDecodedAudioData.slice(Math.floor(startInd * rawDecodedAudioData.length), Math.floor(endInd * rawDecodedAudioData.length));
const numBuckets = Math.floor(AudioWaveform.NUMBER_OF_BUCKETS * zoomFactor);
const bucketDataSize = Math.floor(
decodedAudioData.length / numBuckets
);
const brange = Array.from(Array(bucketDataSize));
const bucketList = numberRange(numBuckets).map(
(i: number) =>
brange.reduce(
(p, x, j) =>
Math.abs(
Math.max(p, decodedAudioData[i * bucketDataSize + j])
),
0
) / 2
);
this.props.layoutDoc[fieldKey] = new List<number>(bucketList);
})
);
}
);
}
render() {
return (
<div className="audioWaveform">
<Waveform
color={Colors.MEDIUM_BLUE}
height={this.waveHeight}
barWidth={200.0 / this.audioBuckets.length}
pos={this.props.duration}
duration={this.props.duration}
peaks={this.audioBuckets}
progressColor={Colors.MEDIUM_BLUE}
/>
</div>
);
}
}
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