AS3 中准确的 BPM 事件监听器 [英] Accurate BPM event listener in AS3

问题描述

我正在尝试以特定 BPM 将动画与音乐同步.我试过使用 Timer，但在处理以毫秒为单位的小间隔时它不准确.我做了一些阅读并找到了一种替代方法，它使用一个小的无声音频文件和 SOUND_COMPLETE 事件作为计时器.

I'm trying to sync animation to music at a specific BPM. I've tried using the Timer but it isn't accurate when dealing with small intervals in milliseconds. I did some reading and found an alternate method that uses a small silent audio file and the SOUND_COMPLETE event as a Timer.

我在这段代码中使用了 167 毫秒长的声音文件.

I used 167ms long sound file with this code.

package
{
    import flash.events.Event;
    import flash.events.EventDispatcher;
    import flash.media.Sound;
    import flash.media.SoundChannel;
    import flash.net.URLRequest;

    public class BetterTimer extends EventDispatcher
    {
        private var silentSound:Sound;

        public function BetterTimer(silentSoundUrl:String):void {
            super();
            silentSound = new Sound( new URLRequest(silentSoundUrl) );
            silentSound.addEventListener(Event.COMPLETE, start);
        }
        public function start():void {
            this.timerFired( new Event("start") );
        }
        private function timerFired(e:Event):void {
            dispatchEvent( new Event("fire") );
            var channel:SoundChannel = silentSound.play();
            channel.addEventListener(Event.SOUND_COMPLETE, timerFired, false, 0, true);
        }
    }
}

这仍然没有保持节拍.Flash Player 的声音是否准确?

This still doesn't stay on beat. Is the Flash Player capable of accuracy with sound?

推荐答案

这很难做到！有一个名为 BeatTimer 的小库试图做到这一点.我自己还没有尝试过这段代码，但如果它按照它声称的那样做，它应该正是您所需要的.

This is very tricky to get right! There's a small lib called BeatTimer that tries to do this. I haven't tried this code myself, but if it does what it claims it should be exactly what you need.

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