Youtube: fix one channel audio

yt-0-fix-one-channel-audio.js

(function (){
var context = new AudioContext();
source = context.createMediaElementSource(document.querySelector('video'));
splitter = context.createChannelSplitter();
merger = context.createChannelMerger();
source.connect(splitter);
splitter.connect(merger, 0, 0);  // first 0 is input channel
splitter.connect(merger, 0, 1);
merger.connect(context.destination);
})();

yt-1-cut-low-freq.js

(function (){
var context = new AudioContext();
source = context.createMediaElementSource(document.querySelector('video'));
splitter = context.createChannelSplitter();
merger = context.createChannelMerger();
source.connect(splitter);
splitter.connect(merger, 0, 0);  // first 0 is input channel
splitter.connect(merger, 0, 1);
let filter = context.createBiquadFilter();
filter.type = "highpass";
filter.frequency.value = 260;
merger.connect(filter);
filter.connect(context.destination);
})();