本文介绍了如何在Java脚本中获得音频的分贝级别的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我目前正在使用JavaScript、HTML和CSS制作一个分贝计可视化工具。
我已经阅读了几个Web Audio API教程,但其中没有任何教程是针对我想要做的事情的。
这是我到目前为止所拥有的:
window.onload = init;
function init() {
var ctx = new webkitAudioContext()
, url = 'https://dl.dropboxusercontent.com/u/86176287/pbjt.mp3'
, audio = new Audio(url)
// 2048 sample buffer, 1 channel in, 1 channel out
, processor = ctx.createJavaScriptNode(2048, 1, 1)
, meter = document.getElementById('meter')
, source;
audio.addEventListener('canplaythrough', function(){
source = ctx.createMediaElementSource(audio);
source.connect(processor);
source.connect(ctx.destination);
processor.connect(ctx.destination);
audio.play();
}, false);
// loop through PCM data and calculate average
// volume for a given 2048 sample buffer
processor.onaudioprocess = function(evt){
var input = evt.inputBuffer.getChannelData(0)
, len = input.length
, total = i = 0
, rms;
while ( i < len ) total += Math.abs( input[i++] );
rms = Math.sqrt( total / len );
meter.style.width = ( rms * 100 ) + '%';
};
}
有人能解释一下我需要做什么,或者给我指个正确的方向吗,因为这似乎不起作用?
推荐答案
已修复
所以我将其更改为:
var audioCtx = new AudioContext();
var url = 'https://dl.dropboxusercontent.com/u/86176287/pbjt.mp3';
var audio = new Audio(url);
var processor = audioCtx.createScriptProcessor(2048, 1, 1);
var meter = document.getElementById('meter');
var source;
audio.addEventListener('canplaythrough', function(){
source = audioCtx.createMediaElementSource(audio);
source.connect(processor);
source.connect(audioCtx.destination);
processor.connect(audioCtx.destination);
//audio.play();
}, false);
// loop through PCM data and calculate average
// volume for a given 2048 sample buffer
processor.onaudioprocess = function(evt){
var input = evt.inputBuffer.getChannelData(0)
, len = input.length
, total = i = 0
, rms;
while ( i < len ) total += Math.abs( input[i++] );
rms = Math.sqrt( total / len );
//console.log(( rms * 100 ));
};
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