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将双声道上混到4声道，模拟环绕输出（适配4扬声器系统）
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// ==UserScript==
// @name 哔哩哔哩音频4声道上混
// @namespace AudioChannelUpmix
// @version 0.4
// @description 将双声道上混到4声道，模拟环绕输出（适配4扬声器系统）
// @copyright 2025, SylviaKaslana(https://space.bilibili.com/35762009)
// @license MIT
// @author SylviaKaslana
// @match https://www.bilibili.com/video/*
// @match https://www.bilibili.com/medialist/play/*
// @match https://www.bilibili.com/list/*
// @match *://www.bilibili.com/festival/*
// @match https://www.bilibili.com/bangumi/play/*
// @match https://live.bilibili.com/*
// @grant none
// @run-at document-end
// ==/UserScript==
"use strict";
class StereoToQuadUpmixer {
constructor(audioContext) {
this.audioContext = audioContext;
this.setupNodes();
this.connectNodes();
}
setupNodes() {
// 输入分离器
this.inputSplitter = this.audioContext.createChannelSplitter(2);
// 基础信号处理
this.leftGain = this.audioContext.createGain();
this.rightGain = this.audioContext.createGain();
this.sumGain = this.audioContext.createGain();
this.diffGain = this.audioContext.createGain();
// 中央信号生成 (L+R)
this.centerMixer = this.audioContext.createGain();
this.centerGain = this.audioContext.createGain();
this.centerGain.gain.value = 0.707; // -3dB
// 环绕信号生成 (L-R)
this.surroundMixer = this.audioContext.createGain();
this.surroundGain = this.audioContext.createGain();
this.surroundGain.gain.value = 0.5;
// 相位处理 - 使用All-pass滤波器模拟90度相移
this.phaseShifterL = this.audioContext.createBiquadFilter();
this.phaseShifterL.type = 'allpass';
this.phaseShifterL.frequency.value = 1000; // 中心频率
this.phaseShifterL.Q.value = 0.707;
this.phaseShifterR = this.audioContext.createBiquadFilter();
this.phaseShifterR.type = 'allpass';
this.phaseShifterR.frequency.value = 1000;
this.phaseShifterR.Q.value = 0.707;
// 反相器
this.inverter = this.audioContext.createGain();
this.inverter.gain.value = -1;
// 频率处理 - 环绕声道低通滤波 (7kHz)
this.surroundLPF_L = this.audioContext.createBiquadFilter();
this.surroundLPF_L.type = 'lowpass';
this.surroundLPF_L.frequency.value = 7000;
this.surroundLPF_L.Q.value = 0.707;
this.surroundLPF_R = this.audioContext.createBiquadFilter();
this.surroundLPF_R.type = 'lowpass';
this.surroundLPF_R.frequency.value = 7000;
this.surroundLPF_R.Q.value = 0.707;
// 高通滤波器 - 低频管理 (80Hz)
this.surroundHPF_L = this.audioContext.createBiquadFilter();
this.surroundHPF_L.type = 'highpass';
this.surroundHPF_L.frequency.value = 80;
this.surroundHPF_L.Q.value = 0.707;
this.surroundHPF_R = this.audioContext.createBiquadFilter();
this.surroundHPF_R.type = 'highpass';
this.surroundHPF_R.frequency.value = 80;
this.surroundHPF_R.Q.value = 0.707;
// 延迟处理 - 后置声道延迟
this.delayL = this.audioContext.createDelay(0.1);
this.delayL.delayTime.value = 0.02; // 20ms
this.delayR = this.audioContext.createDelay(0.1);
this.delayR.delayTime.value = 0.02; // 20ms
// 动态处理 - 压缩器
this.compressorFL = this.audioContext.createDynamicsCompressor();
this.compressorFR = this.audioContext.createDynamicsCompressor();
this.compressorRL = this.audioContext.createDynamicsCompressor();
this.compressorRR = this.audioContext.createDynamicsCompressor();
// 设置压缩器参数
[this.compressorFL, this.compressorFR, this.compressorRL, this.compressorRR].forEach(comp => {
comp.threshold.value = -20;
comp.knee.value = 5;
comp.ratio.value = 3;
comp.attack.value = 0.005;
comp.release.value = 0.05;
});
// 输出增益控制
this.frontLeftGain = this.audioContext.createGain();
this.frontRightGain = this.audioContext.createGain();
this.rearLeftGain = this.audioContext.createGain();
this.rearRightGain = this.audioContext.createGain();
// 设置输出电平
this.frontLeftGain.gain.value = 1.0; // 0dB
this.frontRightGain.gain.value = 1.0; // 0dB
this.rearLeftGain.gain.value = 0.866; // -1.25dB
this.rearRightGain.gain.value = 0.866; // -1.25dB
// 最终输出合并器
this.outputMixer = this.audioContext.createChannelMerger(4);
// 输入输出节点
this.input = this.inputSplitter;
this.output = this.outputMixer;
}
connectNodes() {
// 输入分离
this.inputSplitter.connect(this.leftGain, 0); // 左声道
this.inputSplitter.connect(this.rightGain, 1); // 右声道
// 中央信号路径 (L+R)
this.leftGain.connect(this.centerMixer);
this.rightGain.connect(this.centerMixer);
this.centerMixer.connect(this.centerGain);
// 环绕信号路径 (L-R)
this.leftGain.connect(this.surroundMixer);
this.rightGain.connect(this.surroundMixer);
// 右声道反相后进入环绕混音器
this.rightGain.connect(this.inverter);
this.inverter.connect(this.surroundMixer);
this.surroundMixer.connect(this.surroundGain);
// 相位处理
this.surroundGain.connect(this.phaseShifterL);
this.surroundGain.connect(this.phaseShifterR);
// 频率处理链
this.phaseShifterL.connect(this.surroundLPF_L);
this.surroundLPF_L.connect(this.surroundHPF_L);
this.surroundHPF_L.connect(this.delayL);
this.phaseShifterR.connect(this.surroundLPF_R);
this.surroundLPF_R.connect(this.surroundHPF_R);
this.surroundHPF_R.connect(this.delayR);
// 前置声道路径
// Front Left = Left + Center
this.leftGain.connect(this.frontLeftGain);
this.centerGain.connect(this.frontLeftGain);
this.frontLeftGain.connect(this.compressorFL);
// Front Right = Right + Center
this.rightGain.connect(this.frontRightGain);
this.centerGain.connect(this.frontRightGain);
this.frontRightGain.connect(this.compressorFR);
// 后置声道路径
this.delayL.connect(this.rearLeftGain);
this.rearLeftGain.connect(this.compressorRL);
this.delayR.connect(this.rearRightGain);
this.rearRightGain.connect(this.compressorRR);
// 最终输出
this.compressorFL.connect(this.outputMixer, 0, 0); // Front Left
this.compressorFR.connect(this.outputMixer, 0, 1); // Front Right
this.compressorRL.connect(this.outputMixer, 0, 2); // Rear Left
this.compressorRR.connect(this.outputMixer, 0, 3); // Rear Right
}
// 动态参数调整方法
setRearLevel(level) {
// level: 0.0 - 1.0
this.rearLeftGain.gain.value = level * 0.866;
this.rearRightGain.gain.value = level * 0.866;
}
setCenterLevel(level) {
// level: 0.0 - 1.0
this.centerGain.gain.value = level * 0.707;
}
setSurroundDelay(delayTime) {
// delayTime: 0.0 - 0.1 seconds
this.delayL.delayTime.value = delayTime;
this.delayR.delayTime.value = delayTime;
}
setSurroundCutoff(frequency) {
// frequency: 1000 - 20000 Hz
this.surroundLPF_L.frequency.value = frequency;
this.surroundLPF_R.frequency.value = frequency;
}
// 获取输入输出节点
getInput() {
return this.input;
}
getOutput() {
return this.output;
}
}
setTimeout(function () {
let video = null;
let audioContext = new AudioContext();
let mediaSource = null;
let dest = audioContext.destination;
dest.channelCount = 4;
const upmixer = new StereoToQuadUpmixer(audioContext);
upmixer.output.connect(dest);
setInterval(() => {
let nowVideoHolder = document.getElementsByClassName("bilibili-player-video")[0] ||
document.getElementsByClassName("bpx-player-video-wrap")[0] ||
document.getElementById("live-player") ||
document.getElementsByClassName("container-video")[0];
if (!nowVideoHolder)
return;
let nowVideo = nowVideoHolder.getElementsByTagName("video")[0];
if (!nowVideo || nowVideo === video) return;
video = nowVideo;
try {
mediaSource = audioContext.createMediaElementSource(video);
mediaSource.connect(upmixer.input);
console.log("[4声道填充脚本]", "已连接 B站视频音频并复制声道");
} catch (e) {
console.warn("连接音频源失败，可能是重复连接或跨域限制", e);
}
}, 1000);
}, 100);