javascript:内插数字数组 [英] javascript : interpolate an array of numbers

问题描述

几个月前，我一直在寻找一种对使用HTML5从麦克风捕获的音频数据进行下采样的方法.如果输入是该频率的直接倍数(即48000Hz)，我就需要输出速率为12000Hz，我没有问题，但是对于其他速率(例如44100Hz)，它似乎很复杂.

few months back, I was looking for a way to downsample the audio data captured from mic using HTML5. I needed output rate as 12000Hz, if input was a direct multiplication of that (i.e 48000Hz) I had no problem, but it seemed complicated for other rates( e.g 44100Hz).

在这些情况下，直接向下采样(每4个仅保留1个)将不起作用，因此我想到了插值，但是那时stackoverflow没有解决方案.所以我自己回答.

In these scenarios, direct down sampling( retaining only 1 out every 4) won't work, so I thought of interpolation, but stackoverflow had no solution at that time. So answering it myself.

推荐答案

小提琴演示.

插值数组的代码

function interpolateArray(data, fitCount) {

    var linearInterpolate = function (before, after, atPoint) {
        return before + (after - before) * atPoint;
    };

    var newData = new Array();
    var springFactor = new Number((data.length - 1) / (fitCount - 1));
    newData[0] = data[0]; // for new allocation
    for ( var i = 1; i < fitCount - 1; i++) {
        var tmp = i * springFactor;
        var before = new Number(Math.floor(tmp)).toFixed();
        var after = new Number(Math.ceil(tmp)).toFixed();
        var atPoint = tmp - before;
        newData[i] = linearInterpolate(data[before], data[after], atPoint);
    }
    newData[fitCount - 1] = data[data.length - 1]; // for new allocation
    return newData;
};

使用示例:

var originalArry = [1,5,3];
var newArry = interpolateArray([1,5,3],5);

这篇关于javascript:内插数字数组的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！