generated from tailored/router-template
83 lines
2.0 KiB
TypeScript
83 lines
2.0 KiB
TypeScript
type EncodeWavOptions = {
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numChannels?: number;
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sampleRate?: number;
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byteRate?: number;
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};
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/**
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* 编码pcm文件为wav文件
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* @param rawPCM
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* @param options
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* @returns
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*/
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export function encodeWav(rawPCM: Buffer | string, options?: EncodeWavOptions) {
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if (typeof rawPCM === 'string') {
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rawPCM = Buffer.from(rawPCM, 'binary');
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}
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if (!Buffer.isBuffer(rawPCM)) {
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throw new TypeError('pcm data must be Buffer or string');
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}
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const opt = options || {};
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const sampleRate = opt.sampleRate || 16000;
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const numChannels = opt.numChannels || 1;
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const byteRate = opt.byteRate || 16;
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const buf = rawPCM;
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const header = Buffer.alloc(44);
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header.write('RIFF', 0);
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header.writeUInt32LE(buf.length, 4);
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header.write('WAVE', 8);
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header.write('fmt ', 12);
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header.writeUInt8(16, 16);
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header.writeUInt8(1, 20);
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header.writeUInt8(numChannels, 22);
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header.writeUInt32LE(sampleRate, 24);
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header.writeUInt32LE(byteRate, 28);
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header.writeUInt8(4, 32);
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header.writeUInt8(16, 34);
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header.write('data', 36);
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header.writeUInt32LE(buf.length + 44 - 8, 40);
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return Buffer.concat([header, buf]);
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}
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/**
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* 解码wav文件
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* @param rawWav
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* @returns
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*/
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export function decodeWav(rawWav: Buffer | string) {
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if (typeof rawWav === 'string') {
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rawWav = Buffer.from(rawWav, 'binary');
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}
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if (!Buffer.isBuffer(rawWav)) {
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throw new TypeError('pcm data must be Buffer or string');
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}
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// remove the header of pcm format
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rawWav = rawWav.subarray(44);
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return rawWav;
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}
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export const converter = {
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encodeWav,
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decodeWav,
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};
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/**
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* 生成无声音频
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* @param duration 音频时长（秒）
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* @param sampleRate 采样率
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* @param channels 声道数
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* @returns 无声音频
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*/
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export const generateSilent = (duration: number = 2, sampleRate: number = 16000, channels: number = 1) => {
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const bufferSize = Math.floor(duration * sampleRate * channels * 2); // 2 bytes per sample
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const silent = Buffer.alloc(bufferSize);
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return silent;
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};
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