我开始使用Web Audio Api进行一些实验,希望了解如何在AngularJS中使用它。
我试过的其他Web Audio似乎在Angular中工作,比如创建一个Web音频正弦波等,但我只是不确定以角度加载音频的最佳方法,如果我想能够使用Web Audio API操作它
我天真地尝试将一些函数直接放入一个看似不对的AngularJS控制器 - 下面的代码。
在Chrome开发工具网络标签中,我可以看到应加载的test.mp3通知'无法加载响应数据'。但是文件的路径是正确的,如果我在开发工具中点击它,文件就会打开并开始播放。
非常感谢任何帮助
// Controller and attempt to load audio
(function () {
'use strict';
angular
.module('app')
.controller('mvMainCtrl', mvMainCtrl);
mvMainCtrl.$inject = ['$resource', '$scope', '$http' ];
function mvMainCtrl($scope, $http, $resource) {
var ctx; //audio context
var buf; //audio buffer
//init the sound system
function init() {
console.log("in init");
try {
ctx = new AudioContext();
loadFile();
} catch(e) {
alert('you need webaudio support');
}
}
function loadFile() {
var req = new XMLHttpRequest();
req.open("GET","/app/main/sounds/test.mp3",true);
req.responseType = "arraybuffer";
req.onload = function() {
//decode the loaded data
ctx.decodeAudioData(req.response, function(buffer) {
buf = buffer;
play();
});
};
req.send();
}
loadFile();
function playback() {
var playSound = ctx.createBufferSource();
playSound.buffer = buf;
playSound.connect(ctx.destination);
playSound.start(audioContext.currentTime);
}
playback();
}
})();
答案 0 :(得分:1)
这是一个BufferLoader的实现,可用于加载声音文件数组:
// BufferLoader
function BufferLoader(context, urlList, callback) {
this.context = context;
this.urlList = urlList;
this.onload = callback;
this.bufferList = new Array();
this.loadCount = 0;
}
BufferLoader.prototype.loadBuffer = function(url, index) {
// Load buffer asynchronously
var request = new XMLHttpRequest();
request.open("GET", url, true);
request.responseType = "arraybuffer";
var loader = this;
request.onload = function() {
// Asynchronously decode the audio file data in request.response
loader.context.decodeAudioData(
request.response,
function(buffer) {
if (!buffer) {
alert('error decoding file data: ' + url);
return;
}
loader.bufferList[index] = buffer;
if (++loader.loadCount == loader.urlList.length)
loader.onload(loader.bufferList);
},
function(error) {
console.error('decodeAudioData error', error);
}
);
}
request.onerror = function() {
alert('BufferLoader: XHR error');
}
request.send();
}
BufferLoader.prototype.load = function() {
for (var i = 0; i < this.urlList.length; ++i)
this.loadBuffer(this.urlList[i], i);
}
如何使用它来加载声音:
var sounds = ["assets/test.mp3", "test2.mp3"]
var context = window.AudioContext || window.webkitAudioContext || window.MozAudioContext || window.mozAudioContext;
var loader = new BufferLoader(context, sounds, onComplete);
var audioBuffers;
function onComplete(bufferList){
console.log("Sounds loaded!");
audioBuffers = bufferList;
}
function playSound(i){
// create buffer source node which is used to play a sound one time
var bufferSourceNode = context.createBufferSource();
// set buffer to one of the loaded sounds;
bufferSourceNode.buffer = audioBuffers[i];
// connect to output
bufferSourceNode.connect(context.destination);
// play the sound
bufferSourceNode.start()
}
现在播放你必须打电话的声音:
playSound(0); // play first sound in array of loaded sounds
在您的示例中,我看不到您在play()
中调用的decodeAudioData
函数的定义位置。您可能想要致电playback()
。你也可以在尚未加载声音的控制器初始化时调用播放,这是你不应该做的。
答案 1 :(得分:1)
我遇到了同样的问题,在这个问题上花了几个小时后,我最终找到了一种方法让它发挥作用:
承诺风格:
$http({
method: 'GET',
url: url,
responseType: 'arraybuffer'
}).then(function(response) {
audioContext.decodeAudioData(response.data, function(buffer) {
mainBuffer = buffer
}, function(err) {
console.log(err)
})
})
标准格式:
$http({
method: 'GET',
url: url,
responseType: 'arraybuffer'
}).success(function(data) {
audioContext.decodeAudioData(data, function(buffer) {
mainBuffer = buffer
}, function(err) {
console.log(err)
})
})
使用XMLHttpRequest()
时,文件已损坏, responseType attribut应指定为 arraybuffer 。