2d:null 2e:["$","title",null,{"children":"MIDIPlayer | maddie lim ✨ | Observable"}] 33:T7c0,class MIDIPlayer { constructor(sampleRate, processor) { this.sampleRate = sampleRate; this.processor = processor; this.onStop = null; this.reset(); } reset() { this.flatSequence = []; this.tempo = 500000; this.ppqn = 96; this.eventIndex = 0; this.currentTime = 0; this.playing = false; this.nextEventData = null; this.wait = 1; } advance(sampleRate) { this.sampleRate = sampleRate; if (this.playing) { this.wait--; while (this.playing && this.wait <= 0) { this.playNextEvent(); } } } playMIDI(sequence, ppqn, onStop) { this.reset(); this.ppqn = ppqn; this.flatSequence = sequence.reduce((m, track) => m.concat(track), []); this.flatSequence.sort((a, b) => { const na = (a[0] << 8) + a[1]; const nb = (b[0] << 8) + b[1]; if (na > nb) return 1; if (na < nb) return -1; return 0; }); this.playing = true; this.onStop = onStop; } playNextEvent() { if (this.nextEventData) { this.processMIDI(this.nextEventData); this.nextEventData = null; } if (this.eventIndex >= this.flatSequence.length) { this.playing = false; if (this.onStop) this.onStop(); return; } const event = this.flatSequence[this.eventIndex]; this.eventIndex++; if (event[0] == this.currentTime) { this.processMIDI(event[2]); this.playNextEvent(); } else if (event[0] > this.currentTime) { var diff = event[0] - this.currentTime; this.currentTime = event[0]; this.nextEventData = event[2]; this.wait += (((diff / this.ppqn) * this.tempo) / 1000000) * this.sampleRate; } } processMIDI(eventData) { var status = eventData[0]; if (status == 0xff) { if (eventData[1] == 0x51) { this.tempo = (eventData[3] << 16) + (eventData[4] << 8) + eventData[5]; } } else { this.processor({ data: eventData }); } } }34:[] 31:{"id":"0198c489484d278c","slug":"midiplayer","title":"MIDIPlayer","thumbnail":"55fc68f84377e9403a8350bdfde3bb0468b25665b581275f0175d7094076061d","access_level":"public","create_time":"$D2019-01-08T06:45:29.482Z","update_time":"$D2021-12-27T22:32:48.188Z","view_time":null,"first_public_time":"$D2019-01-08T06:46:17.597Z","has_unpublished_edits":null,"fork":false,"stars":0,"starred":false,"owner":{"type":"team","id":"408ee840d040526a","login":"maddievision","name":"maddie lim ✨","avatar_url":"https://avatars-next.observableusercontent.com/44fc4f0f8be73321b571127eefd9853a031c5c33e9985648c91e6aa827258ce0","tier":"starter_2024"},"version":11,"publish_version":11,"role":null,"authored":false,"authors":[{"type":"individual","id":"578d96c86967f83d","login":"maddievision","name":"maddie lim ✨","avatar_url":"https://avatars-next.observableusercontent.com/44fc4f0f8be73321b571127eefd9853a031c5c33e9985648c91e6aa827258ce0","tier":null}],"members":[{"type":"individual","id":"578d96c86967f83d","login":"maddievision","name":"maddie lim ✨","avatar_url":"https://avatars-next.observableusercontent.com/44fc4f0f8be73321b571127eefd9853a031c5c33e9985648c91e6aa827258ce0","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":{"id":"7d20321a8bc407f1","slug":"audio","title":"MIDI & Audio","owner":{"id":"408ee840d040526a","login":"maddievision","name":"maddie lim ✨"}},"type":"notebook","body":{"title":"MIDIPlayer","cells":[{"id":0,"value":"md`# MIDIPlayer`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2,"value":"$33","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W34","stdlib":"1","titling":"auto"}} 32:"$31:body"