Web音频调度会立即播放

时间:2012-11-15 08:14:05

标签: audio html5-audio web-audio

我正试图以速度设置的方式播放Web Audio中的音符,就像Google Chromium Shiny Drum Machine示例一样。音符随后向下播放,每行包含两个八度音符(演示,go here并在选择音符之前单击Sticky,然后单击开始)

enter image description here

我有一个开始按钮:

$("#start").click(function () {
    noteTime = 0.0;
    startTime = audioCtx.currentTime + 0.005;
    schedule();
});

日程安排功能:

function schedule(){     var currentTime = audioCtx.currentTime;

currentTime -= startTime;

while (noteTime < currentTime + 0.200) {
    var contextPlayTime = noteTime + startTime;

    for (var i = 0; i < theArray.length; i++) {
        if ($("." + rhythmIndex + ".bar" + i).hasClass("selected")) {
            $("." + rhythmIndex + ".bar" + i).effect("highlight", {}, 10);
            playSound($("." + rhythmIndex + ".bar" + i).attr("freq"), 400, contextPlayTime);
        }
    }
    advanceNote();
}

timeoutId = setTimeout("schedule()", 0);

}

和提前音符功能选择下一个演奏音符:

function advanceNote() {
    // Advance time by a 16th note...
    var secondsPerBeat = 60.0 / $("#tempo").slider("option", "value");

    rhythmIndex++;

    if (rhythmIndex == loopLength) {
        rhythmIndex = 0;
    }

    noteTime = secondsPerBeat;
}

最后我的声音播放器:

function playSound(x, y, quick, noteTime) {
    if (soundBuffer) {
        var sound = audioCtx.createBufferSource();
        var gain = audioCtx.createGainNode();
        sound.buffer = soundBuffer;
        sound.playbackRate.value = x / canvas.width * 2;
        sound.connect(gain);
        gain.connect(audioCtx.destination);

        var volume = 0.5;
        gain.gain.value = volume;

        if (quick) {
            sound.noteGrainOn(0., .2, .4);
        } else {
            sound.noteOn(noteTime);
        }
    }
}

问题是,一旦你开始,它会同时播放每个音符而不考虑时间或节奏。当声音每秒继续播放时,这一切都会导致浏览器超载,我不知道会出现什么问题。这里有什么不对劲?

提前致谢!

1 个答案:

答案 0 :(得分:2)

没关系!修复是noteTime是增量的,因此noteTime = secondsPerBeat应该是noteTime += secondsPerBeat;