我正在使用recorderWorker.js和recorder.js 我从这段代码得到的最终输出是44.1khz,2声道(立体声)wav文件。但我的要求是8khz,1声道wav文件。 如何在recorderWorker.js
的帮助下实现这一目标请帮助我解决问题。
recorderWorker.js的代码是
var recLength = 0,
recBuffers = [],
sampleRate;
this.onmessage = function(e){
switch(e.data.command){
case 'init':
init(e.data.config);
break;
case 'record':
record(e.data.buffer);
break;
case 'exportWAV':
exportWAV(e.data.type);
break;
case 'getBuffer':
getBuffer();
break;
case 'clear':
clear();
break;
}
};
function init(config){
sampleRate = config.sampleRate;
}
function record(inputBuffer){
var bufferL = inputBuffer[0];
var bufferR = inputBuffer[1];
var interleaved = interleave(bufferL, bufferR);
recBuffers.push(interleaved);
recLength += interleaved.length;
}
function exportWAV(type){
var buffer = mergeBuffers(recBuffers, recLength);
var dataview = encodeWAV(buffer);
var audioBlob = new Blob([dataview], { type: type });
this.postMessage(audioBlob);
}
function getBuffer() {
var buffer = mergeBuffers(recBuffers, recLength)
this.postMessage(buffer);
}
function clear(){
recLength = 0;
recBuffers = [];
}
function mergeBuffers(recBuffers, recLength){
var result = new Float32Array(recLength);
var offset = 0;
for (var i = 0; i < recBuffers.length; i++){
result.set(recBuffers[i], offset);
offset += recBuffers[i].length;
}
return result;
}
function interleave(inputL, inputR){
var length = inputL.length + inputR.length;
var result = new Float32Array(length);
var index = 0,
inputIndex = 0;
while (index < length){
result[index++] = inputL[inputIndex];
result[index++] = inputR[inputIndex];
inputIndex++;
}
return result;
}
function floatTo16BitPCM(output, offset, input){
for (var i = 0; i < input.length; i++, offset+=2){
var 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 (var i = 0; i < string.length; i++){
view.setUint8(offset + i, string.charCodeAt(i));
}
}
function encodeWAV(samples){
var buffer = new ArrayBuffer(44 + samples.length * 2);
var view = new DataView(buffer);
/* RIFF identifier */
writeString(view, 0, 'RIFF');
/* file length */
view.setUint32(4, 32 + samples.length * 2, 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, 1, true);
/* channel count */
view.setUint16(22, 2, true);
/* sample rate */
view.setUint32(24, sampleRate, true);
/* byte rate (sample rate * block align) */
view.setUint32(28, sampleRate * 4, true);
/* block align (channel count * bytes per sample) */
view.setUint16(32, 4, true);
/* bits per sample */
view.setUint16(34, 16, true);
/* data chunk identifier */
writeString(view, 36, 'data');
/* data chunk length */
view.setUint32(40, samples.length * 2, true);
floatTo16BitPCM(view, 44, samples);
return view;
}
答案 0 :(得分:0)
您不需要修改Recorder.JS库 - 已提供此功能。构造函数接受配置对象作为第二个参数,如下所示:
var audioContext = new AudioContext();
var microphone = audioContext.createMediaStreamSource(stream);
recorder = new Recorder(microphone, { numChannels: 1, sampleRate: 8000 });