Question

我有以下代码来播放加载到缓冲区中的特定声音。

sound1.gainNode = context.createGain();
sound1.source = context.createBufferSource();
sound1.source.buffer = soundBuffers[num];
sound1.source.connect(sound1.gainNode);
sound1.gainNode.connect(context.destination);
sound1.source.looping = true;
sound1.source.start(0);

以下是我如何调用更改量方法：

<input type="range" min="0" max="100" value="70" id="playBtn1_vol" onchange="changeVolume(this,sound1Gain)" style="display:none">

这是变更量方法：

function changeVolume = function(element,soundNo){
      var volume = element.value;
      var fraction = parseInt(element.value) / parseInt(element.max);
      // Using an x^2 progression as it gives a better sound than linear.
      soundNo.gainNode.gain.value = fraction * fraction;
    };

在我尝试使用增益使音量工作之前，它播放得很好，但现在已经坏了，我无法找到它的错误。如果有人能指出我正确的方向，那将非常感激。

Answer 1

这里的示例代码（js）可以帮助你。 Reference

var VolumeSample = {
};

// Gain node needs to be mutated by volume control.
VolumeSample.gainNode = null;

VolumeSample.play = function() {
  if (!context.createGain)
    context.createGain = context.createGainNode;
  this.gainNode = context.createGain();
  var source = context.createBufferSource();
  source.buffer = BUFFERS.techno;

  // Connect source to a gain node
  source.connect(this.gainNode);
  // Connect gain node to destination
  this.gainNode.connect(context.destination);
  // Start playback in a loop
  source.loop = true;
  if (!source.start)
    source.start = source.noteOn;
  source.start(0);
  this.source = source;
};

VolumeSample.changeVolume = function(element) {
  var volume = element.value;
  var fraction = parseInt(element.value) / parseInt(element.max);
  // Let's use an x*x curve (x-squared) since simple linear (x) does not
  // sound as good.
  this.gainNode.gain.value = fraction * fraction;
};

VolumeSample.stop = function() {
  if (!this.source.stop)
    this.source.stop = source.noteOff;
  this.source.stop(0);
};

VolumeSample.toggle = function() {
  this.playing ? this.stop() : this.play();
  this.playing = !this.playing;
};

Answer 2

这会使用音量小部件呈现网络音频 - 只需更新mp3，其中包含指向实际文件的路径或指向此类

的某个网址

<html>
<head>
    <title>render audio with volume control</title>
</head>

<body>

    <p>Volume</p>
    <input id="volume" type="range" min="0" max="1" step="0.1" value="0.5"/>

    <script>

    var audio_context = null;
    var gain_node = null;

    window.AudioContext = window.AudioContext || window.webkitAudioContext;
    audio_context = new AudioContext();

    gain_node = audio_context.createGain(); // Declare gain node
    gain_node.connect(audio_context.destination); // Connect gain node to speakers

    function render_audio() {

        var request = new XMLHttpRequest();

        var audio_url = "put_your_music_file_here.mp3";

        request.open('GET', audio_url, true); // loading local file for now
        request.responseType = 'arraybuffer';

        // Decode asynchronously
        request.onload = function() {

            audio_context.decodeAudioData(request.response, function(buffer) {

                stored_buffer = buffer; // store buffer for replay later

                var source = audio_context.createBufferSource(); // creates a sound source
                source.buffer = buffer;                    // tell the source which sound to play
                source.connect(gain_node);       // connect source to speakers
                source.start(0);                           // play the source now
            });
        };
        request.send();
    }

    // --- enable volume control for output speakers

    document.getElementById('volume').addEventListener('change', function() {

      var curr_volume = this.value;
      gain_node.gain.value = curr_volume;

      console.log("curr_volume ", curr_volume);
    });


    // init
    render_audio();

    </script>

      <body onkeypress="render_audio()">

    <button onclick="render_audio()">play_again</button>

</body>
</html>

Answer 3

我解决了这个问题，我认为这与线条或标签或其他东西的排序有关。我有这个：

sound1.gainNode = context.createGain();
sound1.source = context.createBufferSource();
sound1.source.buffer = soundBuffers[num];
sound1.source.connect(sound1.gainNode);
sound1.gainNode.connect(context.destination);
sound1.source.looping = true;
sound1.source.start(0);

我将其更新为：

        source1 = context.createBufferSource();
        gain1 = context.createGain();
            gain1.gain.value=parseFloat(document.getElementById('playBtn'+num+'_vol').value);our currently playing sound.
        source1.buffer = soundBuffers[num];
        source1.connect(gain1);
        gain1.connect(context.destination);
        source1.looping = true;
        source1[source1.start ? 'start' : 'noteOn'](0);

现在它有效。可能是一个新手的错误，但希望这会帮助其他人开始使用Web Audio。

Web音频无法播放

3 个答案: