@remotion/media-utils/dist/audio-buffer/audio-buffer-to-wav.js

Utilities for working with media files

"use strict";
/**
 * Inlined from https://github.com/Jam3/audiobuffer-to-wav/commit/2272eb09bd46a05e50a6d684d908aa6f13c58f63#diff-e727e4bdf3657fd1d798edcd6b099d6e092f8573cba266154583a746bba0f346
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.audioBufferToWav = audioBufferToWav;
function interleave(inputL, inputR) {
    const length = inputL.length + inputR.length;
    const result = new Float32Array(length);
    let index = 0;
    let inputIndex = 0;
    while (index < length) {
        result[index++] = inputL[inputIndex];
        result[index++] = inputR[inputIndex];
        inputIndex++;
    }
    return result;
}
function writeFloat32(output, offset, input) {
    for (let i = 0; i < input.length; i++, offset += 4) {
        output.setFloat32(offset, input[i], true);
    }
}
function floatTo16BitPCM(output, offset, input) {
    for (let i = 0; i < input.length; i++, offset += 2) {
        const s = Math.max(-1, Math.min(1, input[i]));
        output.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7fff, true);
    }
}
function writeString(view, offset, string) {
    for (let i = 0; i < string.length; i++) {
        view.setUint8(offset + i, string.charCodeAt(i));
    }
}
function encodeWAV({ samples, format, sampleRate, numChannels, bitDepth, }) {
    const bytesPerSample = bitDepth / 8;
    const blockAlign = numChannels * bytesPerSample;
    const buffer = new ArrayBuffer(44 + samples.length * bytesPerSample);
    const view = new DataView(buffer);
    /* RIFF identifier */
    writeString(view, 0, 'RIFF');
    /* RIFF chunk length */
    view.setUint32(4, 36 + samples.length * bytesPerSample, true);
    /* RIFF type */
    writeString(view, 8, 'WAVE');
    /* format chunk identifier */
    writeString(view, 12, 'fmt ');
    /* format chunk length */
    view.setUint32(16, 16, true);
    /* sample format (raw) */
    view.setUint16(20, format, true);
    /* channel count */
    view.setUint16(22, numChannels, true);
    /* sample rate */
    view.setUint32(24, sampleRate, true);
    /* byte rate (sample rate * block align) */
    view.setUint32(28, sampleRate * blockAlign, true);
    /* block align (channel count * bytes per sample) */
    view.setUint16(32, blockAlign, true);
    /* bits per sample */
    view.setUint16(34, bitDepth, true);
    /* data chunk identifier */
    writeString(view, 36, 'data');
    /* data chunk length */
    view.setUint32(40, samples.length * bytesPerSample, true);
    if (format === 1) {
        // Raw PCM
        floatTo16BitPCM(view, 44, samples);
    }
    else {
        writeFloat32(view, 44, samples);
    }
    return buffer;
}
function audioBufferToWav(buffer, opt) {
    const numChannels = buffer.numberOfChannels;
    const { sampleRate } = buffer;
    const format = opt.float32 ? 3 : 1;
    const bitDepth = format === 3 ? 32 : 16;
    let result;
    if (numChannels === 2) {
        result = interleave(buffer.getChannelData(0), buffer.getChannelData(1));
    }
    else {
        result = buffer.getChannelData(0);
    }
    return encodeWAV({
        samples: result,
        format,
        sampleRate,
        numChannels,
        bitDepth,
    });
}