HTML5网页录音和压缩,边猜边做..(附源码)

原文:HTML5网页录音和压缩,边猜边做..(附源码)

最近公司需要用到web录音的功能

本人接手了这个任务

在网上找了一些资料

http://www.jsjtt.com/webkaifa/html5/2013-08-28/34.html

http://javascript.ruanyifeng.com/bom/webrtc.html

讲的都差不多

也就是怎么使用 getUserMedia

下载来的栗子也比较简单,可以直接运行

问题1:怎么上传

栗子中最后返回的是Blob数据

return new Blob([dataview], { type: type })

因为对html5不熟,所以又查了一些数据

原来HTML5中使用FormData这个对象好方便

var fd = new FormData();
fd.append("audioData", blob);
var xhr = new XMLHttpRequest();
xhr.open("POST", url);
xhr.send(fd);

在C#服务器端 如下代码就可以接收了

public void ProcessRequest(HttpContext context)
{
if (context.Request.Files.Count > 0)
{
context.Request.Files[0].SaveAs("d:\\1.wav");
}
}

问题2:文件体积太大

是的,使用上面的栗子,直接录音保存后基本上2秒就需要400K,一段20秒的录音就达到了的4M

这样的数据根本无法使用,必须想办法压缩数据

我开始尝试读每一段代码

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;
}

上面的代码,就是把字节数据格式化成wav的格式的过程

所以我又去查了wav的头文件

(function (window) {
//兼容
window.URL = window.URL || window.webkitURL;
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;

var HZRecorder = function (stream, config) {
config = config || {};
config.sampleBits = config.sampleBits || 8;      //采样数位 8, 16
config.sampleRate = config.sampleRate || (44100 / 6);   //采样率(1/6 44100)

var context = new webkitAudioContext();
var audioInput = context.createMediaStreamSource(stream);
var recorder = context.createJavaScriptNode(4096, 1, 1);

var audioData = {
size: 0          //录音文件长度
, buffer: []     //录音缓存
, inputSampleRate: context.sampleRate    //输入采样率
, inputSampleBits: 16       //输入采样数位 8, 16
, outputSampleRate: config.sampleRate    //输出采样率
, oututSampleBits: config.sampleBits       //输出采样数位 8, 16
, input: function (data) {
this.buffer.push(new Float32Array(data));
this.size += data.length;
}
, compress: function () { //合并压缩
//合并
var data = new Float32Array(this.size);
var offset = 0;
for (var i = 0; i < this.buffer.length; i++) {
data.set(this.buffer[i], offset);
offset += this.buffer[i].length;
}
//压缩
var compression = parseInt(this.inputSampleRate / this.outputSampleRate);
var length = data.length / compression;
var result = new Float32Array(length);
var index = 0, j = 0;
while (index < length) {
result[index] = data[j];
j += compression;
index++;
}
return result;
}
, encodeWAV: function () {
var sampleRate = Math.min(this.inputSampleRate, this.outputSampleRate);
var sampleBits = Math.min(this.inputSampleBits, this.oututSampleBits);
var bytes = this.compress();
var dataLength = bytes.length * (sampleBits / 8);
var buffer = new ArrayBuffer(44 + dataLength);
var data = new DataView(buffer);

var channelCount = 1;//单声道
var offset = 0;

var writeString = function (str) {
for (var i = 0; i < str.length; i++) {
data.setUint8(offset + i, str.charCodeAt(i));
}
}

// 资源交换文件标识符
writeString('RIFF'); offset += 4;
// 下个地址开始到文件尾总字节数,即文件大小-8
data.setUint32(offset, 36 + dataLength, true); offset += 4;
// WAV文件标志
writeString('WAVE'); offset += 4;
// 波形格式标志
writeString('fmt '); offset += 4;
// 过滤字节,一般为 0x10 = 16
data.setUint32(offset, 16, true); offset += 4;
// 格式类别 (PCM形式采样数据)
data.setUint16(offset, 1, true); offset += 2;
// 通道数
data.setUint16(offset, channelCount, true); offset += 2;
// 采样率,每秒样本数,表示每个通道的播放速度
data.setUint32(offset, sampleRate, true); offset += 4;
// 波形数据传输率 (每秒平均字节数) 单声道×每秒数据位数×每样本数据位/8
data.setUint32(offset, channelCount * sampleRate * (sampleBits / 8), true); offset += 4;
// 快数据调整数 采样一次占用字节数 单声道×每样本的数据位数/8
data.setUint16(offset, channelCount * (sampleBits / 8), true); offset += 2;
// 每样本数据位数
data.setUint16(offset, sampleBits, true); offset += 2;
// 数据标识符
writeString('data'); offset += 4;
// 采样数据总数,即数据总大小-44
data.setUint32(offset, dataLength, true); offset += 4;
// 写入采样数据
if (sampleBits === 8) {
for (var i = 0; i < bytes.length; i++, offset++) {
var s = Math.max(-1, Math.min(1, bytes[i]));
var val = s < 0 ? s * 0x8000 : s * 0x7FFF;
val = parseInt(255 / (65535 / (val + 32768)));
data.setInt8(offset, val, true);
}
} else {
for (var i = 0; i < bytes.length; i++, offset += 2) {
var s = Math.max(-1, Math.min(1, bytes[i]));
data.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true);
}
}

return new Blob([data], { type: 'audio/wav' });
}
};

//开始录音
this.start = function () {
audioInput.connect(recorder);
recorder.connect(context.destination);
}

//停止
this.stop = function () {
recorder.disconnect();
}

//获取音频文件
this.getBlob = function () {
this.stop();
return audioData.encodeWAV();
}

//回放
this.play = function (audio) {
audio.src = window.URL.createObjectURL(this.getBlob());
}

//上传
this.upload = function (url, callback) {
var fd = new FormData();
fd.append("audioData", this.getBlob());
var xhr = new XMLHttpRequest();
if (callback) {
xhr.upload.addEventListener("progress", function (e) {
callback('uploading', e);
}, false);
xhr.addEventListener("load", function (e) {
callback('ok', e);
}, false);
xhr.addEventListener("error", function (e) {
callback('error', e);
}, false);
xhr.addEventListener("abort", function (e) {
callback('cancel', e);
}, false);
}
xhr.open("POST", url);
xhr.send(fd);
}

//音频采集
recorder.onaudioprocess = function (e) {
audioData.input(e.inputBuffer.getChannelData(0));
//record(e.inputBuffer.getChannelData(0));
}

};
//抛出异常
HZRecorder.throwError = function (message) {
alert(message);
throw new function () { this.toString = function () { return message; } }
}
//是否支持录音
HZRecorder.canRecording = (navigator.getUserMedia != null);
//获取录音机
HZRecorder.get = function (callback, config) {
if (callback) {
if (navigator.getUserMedia) {
navigator.getUserMedia(
{ audio: true } //只启用音频
, function (stream) {
var rec = new HZRecorder(stream, config);
callback(rec);
}
, function (error) {
switch (error.code || error.name) {
case 'PERMISSION_DENIED':
case 'PermissionDeniedError':
HZRecorder.throwError('用户拒绝提供信息。');
break;
case 'NOT_SUPPORTED_ERROR':
case 'NotSupportedError':
HZRecorder.throwError('浏览器不支持硬件设备。');
break;
case 'MANDATORY_UNSATISFIED_ERROR':
case 'MandatoryUnsatisfiedError':
HZRecorder.throwError('无法发现指定的硬件设备。');
break;
default:
HZRecorder.throwError('无法打开麦克风。异常信息:' + (error.code || error.name));
break;
}
});
} else {
HZRecorder.throwErr('当前浏览器不支持录音功能。'); return;
}
}
}

window.HZRecorder = HZRecorder;

})(window);

js

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
</head>
<body>
<div>
<audio controls autoplay></audio>
<input onclick="startRecording()" type="button" value="录音" />
<input onclick="stopRecording()" type="button" value="停止" />
<input onclick="playRecording()" type="button" value="播放" />
<input onclick="uploadAudio()" type="button" value="提交" />
</div>

<script type="text/javascript" src="HZRecorder.js"></script>

<script>

var recorder;

var audio = document.querySelector('audio');

function startRecording() {
HZRecorder.get(function (rec) {
recorder = rec;
recorder.start();
});
}

function stopRecording() {
recorder.stop();
}

function playRecording() {
recorder.play(audio);
}

function uploadAudio() {
recorder.upload("Handler1.ashx", function (state, e) {
switch (state) {
case 'uploading':
//var percentComplete = Math.round(e.loaded * 100 / e.total) + '%';
break;
case 'ok':
//alert(e.target.responseText);
alert("上传成功");
break;
case 'error':
alert("上传失败");
break;
case 'cancel':
alert("上传被取消");
break;
}
});
}

</script>

</body>
</html>

好了 下班了

源码下载: RecordingDemo.rar

demo默认采用 44100/6 的采样率 ,原来20秒要4M ,单声道砍一半 2M ,8位砍一半 1M, 6分之一采样率 1M/6 170K左右

微信4秒只有4K是怎么做到的?