如何通过javascript/html5播放wav音频字节数组？

Question

我正在使用以下方法来播放包含wav数据的字节数组.该函数正在从GWT项目中调用.

此功能播放声音,但它听起来像某种地狱怪物.采样率肯定是正确的(声音是由neospeech生成的)我已经为numberOfSamples尝试了各种值,这似乎只代表音频数据的长度.

numberOfSamples的值大于30000将播放音频文件的全长,但它是乱码且可怕的.

那么,我做错了什么？

function playByteArray(byteArray, numberOfSamples) {
    sampleRate = 8000;

    if (!window.AudioContext) {
        if (!window.webkitAudioContext) {
            alert("Your browser does not support any AudioContext and cannot play back this audio.");
            return;
        }
        window.AudioContext = window.webkitAudioContext;
    }

    var audioContext = new AudioContext();

    var buffer = audioContext.createBuffer(1, numberOfSamples, sampleRate);
    var buf = buffer.getChannelData(0);
    for (i = 0; i < byteArray.length; ++i) {
        buf[i] = byteArray[i];
    }

    var source = audioContext.createBufferSource();
    source.buffer = buffer;
    source.connect(audioContext.destination);
    source.start(0);
}

Answer 1

我想出了如何做我在我的问题中所描述的内容,并认为我应该发布它以造福他人.代码如下.我调用playByteArray并传递一个包含pcm wav数据的字节数组.

window.onload = init;
var context;    // Audio context
var buf;        // Audio buffer

function init() {
if (!window.AudioContext) {
    if (!window.webkitAudioContext) {
        alert("Your browser does not support any AudioContext and cannot play back this audio.");
        return;
    }
        window.AudioContext = window.webkitAudioContext;
    }

    context = new AudioContext();
}

function playByteArray(byteArray) {

    var arrayBuffer = new ArrayBuffer(byteArray.length);
    var bufferView = new Uint8Array(arrayBuffer);
    for (i = 0; i < byteArray.length; i++) {
      bufferView[i] = byteArray[i];
    }

    context.decodeAudioData(arrayBuffer, function(buffer) {
        buf = buffer;
        play();
    });
}

// Play the loaded file
function play() {
    // Create a source node from the buffer
    var source = context.createBufferSource();
    source.buffer = buf;
    // Connect to the final output node (the speakers)
    source.connect(context.destination);
    // Play immediately
    source.start(0);
}

Answer 2

清理建议：

function playByteArray( bytes ) {
    var buffer = new Uint8Array( bytes.length );
    buffer.set( new Uint8Array(bytes), 0 );

    context.decodeAudioData(buffer.buffer, play);
}

function play( audioBuffer ) {
    var source = context.createBufferSource();
    source.buffer = audioBuffer;
    source.connect( context.destination );
    source.start(0);
}