@omnimedia/omnitool/x/timeline/parts/waveform.js

open source video processing tools

import WaveSurfer from "wavesurfer.js";
import { context } from "../../context.js";
export class Waveform {
    wavesurfer;
    constructor(peaks, container, duration) {
        this.wavesurfer = WaveSurfer.create({
            container,
            waveColor: 'rgb(200, 0, 200)',
            progressColor: 'rgb(100, 0, 100)',
            barWidth: 10,
            barRadius: 10,
            barGap: 2,
            peaks: [peaks],
            duration
        });
    }
    static async init(source, container) {
        const driver = await context.driver;
        const reader = driver.decode({ source }).audio.getReader();
        const peaks = [];
        let buffer = [];
        const samplesPerPeak = 1024;
        const duration = await driver.getAudioDuration(source);
        while (true) {
            const { done, value: audioData } = await reader.read();
            if (done)
                break;
            const frames = audioData.numberOfFrames;
            const plane = new Float32Array(frames);
            audioData.copyTo(plane, { planeIndex: 0 }); // Use left channel only
            for (let i = 0; i < plane.length; i++) {
                buffer.push(plane[i]);
                if (buffer.length >= samplesPerPeak) {
                    const chunk = buffer.splice(0, samplesPerPeak);
                    const min = Math.min(...chunk);
                    const max = Math.max(...chunk);
                    peaks.push(min, max);
                }
            }
            audioData.close();
        }
        return new Waveform(peaks, container, duration ?? 0);
    }
    // set zoom(value: number) {
    // 	this.wavesurfer.zoom(value)
    // }
    set width(value) {
        this.wavesurfer.setOptions({ width: value });
    }
}
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