我正在尝试设置一些网络音频以同时加载/播放多个声源。
目前正在加载声音,并通过按钮输入触发播放。

我的问题是,我希望所有声音都通过一个BiquadFilter运行(在这种情况下,类型为0; // LOWPASS过滤器)。
我相信我已经正确地创建了滤波器(在两个不同的地方,不确定在哪个地方看所附的代码),但是我无法获得用于控制频率的范围输入,某些通信无法很好地进行并且完全丢失。

另外,围绕同一主题,我希望每个声音都通过各自独立的gainNodes(音量控件)运行,这又将通过范围输入进行更改。
基本上会有6个音频文件,它们通过它们自己的gainNodes运行,然后聚集在一起经过LOWPASS滤波器,然后到达目的地(即扬声器)。

我希望可以遍历各个pannerNode,但目前面临着一起放弃该项目的机会。

下面是我的代码(就像我之前说过的那样,按钮触发了所有声音,但是过滤器是一个大问题):

HTML:

<body>

<div id="startbtn">
<p><input type="button" onClick="tracks.toggle();">PLAY!</p>
</div> <!-- startbtn div -->

<div id="frequency">
<p><input type="range" id="freq1" min="0" max="1" step="0.01" value="1"     onchange="sound.changeFrequency(this);" style="width:180px; background-color:#FFF;">    Frequency</p>
</p>
</div>

<script>
var tracks = new SongTracks();
var sound = new playSound();
</script>
</body>

JAVASCRIPT:
var context = new webkitAudioContext();
var myAudioAnalyser;

  function init() {
            if('webkitAudioContext' in window) {
                myAudioContext = new webkitAudioContext();
                // an analyser is used for the spectrum
                myAudioAnalyser = myAudioContext.createAnalyser();
                myAudioAnalyser.smoothingTimeConstant = 0.85;
                myAudioAnalyser.connect(myAudioContext.destination);

               fetchSounds();
              };
            };


// shim layer with setTimeout fallback
window.requestAnimFrame = (function(){
return  window.requestAnimationFrame       ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame    ||
window.oRequestAnimationFrame      ||
window.msRequestAnimationFrame     ||
function( callback ){
window.setTimeout(callback, 1000 / 60);
};
})();


function playSound(buffer, time) {
  var source = context.createBufferSource();
  source.buffer = buffer;

 var filter = context.createBiquadFilter();  ///////////////// HERE
 filter.type = filter.LOWPASS;
 filter.frequency.value = 5000;

 source.connect(filter);
 filter.connect(context.destination);
 source.start(time);

this.filter = filter;

};

function loadSounds(obj, soundMap, callback) {

var names = []
var paths = []
for (var name in soundMap) {
    var path = soundMap[name];
    names.push(name);
    paths.push(path);
}
bufferLoader = new BufferLoader(context, paths, function(bufferList) {
    for (var i = 0; i < bufferList.length; i++) {
        var buffer = bufferList[i];
        var name = names[i];
        obj[name] = buffer;
    }
    if (callback) {
        callback();
    }
});
bufferLoader.load();
};

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);
};

var SongTracks = function() {
  loadSounds(this, {
    vocals: 'tracks/vocals.mp3',
    guitar: 'tracks/guitar.mp3',
    piano: 'tracks/piano.mp3'
  });
};

var filter;

SongTracks.prototype.play = function() {
    playSound(this.vocals, 0);
    playSound(this.guitar, 0);
    playSound(this.piano, 0);
///////////////////////////////////////////////////////////// OR HERE
var source1 = context.createBufferSource();
source1.buffer = this.buffer
source1 = bufferList[0];


var filter = context.createBiquadFilter();
filter.type = filter.LOWPASS;
filter.frequency.value = 5000;

source1.connect(filter);
filter.connect(context.destination);

this.filter = filter;
///////////////////////////////////////////////////////////////////// TO HERE?
};

  SongTracks.prototype.stop = function() {
  this.source.stop(0);
};

SongTracks.prototype.toggle = function() {
  this.isPlaying ? this.stop() : this.play();
  this.isPlaying = !this.isPlaying;
};

/* SongTracks.prototype.changeFrequency = function(element) {
var minValue = 40;
var maxValue = context.sampleRate / 2;

var numberOfOctaves = Math.log(maxValue / minValue) / Math.LN2;
var multiplier = Math.pow(2, numberOfOctaves * (element.value - 1.0));
this.filter.frequency.value = maxValue * multiplier;
}; */

playSound.prototype.changeFrequency = function(element) {
var minValue = 40;
var maxValue = context.sampleRate / 2;

var numberOfOctaves = Math.log(maxValue / minValue) / Math.LN2;
var multiplier = Math.pow(2, numberOfOctaves * (element.value - 1.0));
this.filter.frequency.value = maxValue * multiplier;
};


</script>

如您所见,通过我的笔记等,我非常困惑,有点撞墙了。
我看过区分音频文件的代码,类似;
   var source1 = context.createBufferSource();
   var source2 = context.createBufferSource();
   var source3 = context.createBufferSource();
   var source4 = context.createBufferSource();

  source1.buffer = bufferList[0];
  source2.buffer = bufferList[1];
  source3.buffer = bufferList[2];
  source4.buffer = bufferList[3];

但是我不知道,祝你好运。

最佳答案

您可能应该简单地将要连接的节点传递到playSound中,然后将其传递给FilterNode。

在playSound内创建BiquadFilter的位置不正确-您最终将创建N个,每个播放声音一个,而只想要一个。

您想要类似的东西:

HTML文件相同,除了:

<input type="range" id="freq1" min="0" max="1" step="0.01" value="1" onchange="changeFilterFrequency(this);" style="width:180px; background-color:#FFF;">    Frequency</p>

JS:
function playSound(buffer, outputNode, time) {
    var source = context.createBufferSource();
    source.buffer = buffer;

    source.connect(outputNode);
    source.start(time);
}

var globalFilter = null;  // one global filter

SongTracks.prototype.play = function() {
    var globalFilter = context.createBiquadFilter();
    globalFilter.type = globalFilter.LOWPASS;
    globalFilter.frequency.value = 5000;
    globalFilter.connect(context.destination);

    playSound(this.vocals, globalFilter, 0);
    playSound(this.guitar, globalFilter, 0);
    playSound(this.piano, globalFilter, 0);
};

function changeFilterFrequency(element) {
    var minValue = 40;
    var maxValue = context.sampleRate / 2;

    var numberOfOctaves = Math.log(maxValue / minValue) / Math.LN2;
    var multiplier = Math.pow(2, numberOfOctaves * (element.value - 1.0));
    globalFilter.frequency.value = maxValue * multiplier;
}

10-06 09:00
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