如何使用 ScriptProcessorNode 执行简单的线性重采样？

Question

我目前正在尝试使用 ScriptProcessorNode 动态降低播放速度。这是我到目前为止一起破解的代码（只处理左声道）：

let processor = audioContext.createScriptProcessor(2**14);
let stored = [];
let currIndex = 0;
let playbackRate = 0.666;

processor.onaudioprocess = (e) => {
    let leftChannel = e.inputBuffer.getChannelData(0);
    for (let i = 0; i < leftChannel.length; i++) stored.push(leftChannel[i]);
    let outputLeft = e.outputBuffer.getChannelData(0);

    for (let i = 0; i < outputLeft.length; i++) {
        let otherIndex = currIndex + i * playbackRate;
        let completion = otherIndex % 1;
        let otherSampleLow = stored[Math.floor(otherIndex)];
        let otherSampleHigh = stored[Math.ceil(otherIndex)];

        let val = (completion-1)*otherSampleLow + completion*otherSampleHigh;
        outputLeft[i] = val;
    }

    currIndex += Math.floor(leftChannel.length * playbackRate);
};

let osc = audioContext.createOscillator();
osc.frequency.value = 440;
osc.connect(processor);
osc.start();

然而，对于任何小于 1 的播放速率，这听起来都像是垃圾。这是为什么呢？我是不是太天真了，以为我可以通过在信号之间进行线性插值来减慢音频信号的速度？

这里是 fiddle：https://jsfiddle.net/6Le7aq42/

Answer 1

知道了，错误是 (completion - 1) 而不是 (1 - completion)。

如何使用 ScriptProcessorNode 执行简单的线性重采样？

How do I perform simple linear resampling using a ScriptProcessorNode?

javascript

web-audio-api

resampling