Question

我正在尝试使用我在this page上找到的示例为我的在线广播流使用音频可视化。但是，类似于this post中发现的问题，我的音频文件（即使在使用本地文件进行测试时）听起来也不合适，当然可视化也没有任何效果。

我的HTML如下：

<html>
   <head>
     <link rel="stylesheet" type="text/css" href="style.css">
   </head>
   <body>
     <audio src="http://50.22.218.101:38838/;steam.mp3" id="audio" 
     controls>HTML5 Audio element not supported</audio>
     <canvas id="canvas" width="800" height="350"></canvas>
     <script src="main.js"></script>
   </body>
</html>

这是“main.js”：

window.AudioContext = window.AudioContext || window.webkitAudioContext || window.mozAudioContext;

window.onload = function() {
    var audio = document.getElementById('audio');
    var ctx = new AudioContext();
    var analyser = ctx.createAnalyser();
    var audioSrc = ctx.createMediaElementSource(audio);
    // we have to connect the MediaElementSource with the analyser 
    audioSrc.connect(analyser);
    analyser.connect(ctx.destination);
    // we could configure the analyser: e.g. analyser.fftSize (for further infos read the spec)
    // analyser.fftSize = 64;
    // frequencyBinCount tells you how many values you'll receive from the analyser
    var frequencyData = new Uint8Array(analyser.frequencyBinCount);

    // we're ready to receive some data!
    var canvas = document.getElementById('canvas'),
        cwidth = canvas.width,
        cheight = canvas.height - 2,
        meterWidth = 10, //width of the meters in the spectrum
        gap = 2, //gap between meters
        capHeight = 2,
        capStyle = '#fff',
        meterNum = 800 / (10 + 2), //count of the meters
        capYPositionArray = []; ////store the vertical position of hte caps for the preivous frame
    ctx = canvas.getContext('2d'),
    gradient = ctx.createLinearGradient(0, 0, 0, 300);
    gradient.addColorStop(1, '#0f0');
    gradient.addColorStop(0.5, '#ff0');
    gradient.addColorStop(0, '#f00');
    // loop
    function renderFrame() {
        var array = new Uint8Array(analyser.frequencyBinCount);
        analyser.getByteFrequencyData(array);
        var step = Math.round(array.length / meterNum); //sample limited data from the total array
        ctx.clearRect(0, 0, cwidth, cheight);
        for (var i = 0; i < meterNum; i++) {
            var value = array[i * step];
            if (capYPositionArray.length < Math.round(meterNum)) {
                capYPositionArray.push(value);
            };
            ctx.fillStyle = capStyle;
            //draw the cap, with transition effect
            if (value < capYPositionArray[i]) {
                ctx.fillRect(i * 12, cheight - (--capYPositionArray[i]), meterWidth, capHeight);
            } else {
                ctx.fillRect(i * 12, cheight - value, meterWidth, capHeight);
                capYPositionArray[i] = value;
            };
            ctx.fillStyle = gradient; //set the filllStyle to gradient for a better look
            ctx.fillRect(i * 12 /*meterWidth+gap*/ , cheight - value + capHeight, meterWidth, cheight); //the meter
        }
        requestAnimationFrame(renderFrame);
    }
    renderFrame();
    audio.play();
};

知道我做错了什么吗？

Answer 1

您通常只需在html音频广告代码中添加crossorigin选项即可解决此问题

所以这个：

<audio src="http://50.22.218.101:38838/;steam.mp3" id="audio" controls>

成为这个：

<audio src="http://50.22.218.101:38838/;steam.mp3" crossorigin="anonymous" id="audio" controls>

使用HTML5创建音频可视化工具

1 个答案: