75 lines
2.9 KiB
TypeScript
75 lines
2.9 KiB
TypeScript
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import { TapeData } from '../types';
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import Apple2IO from '../apple2io';
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import { debug } from '../util';
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export const TAPE_TYPES = ['wav', 'aiff', 'aif', 'mp3', 'm4a'] as const;
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export default class Tape {
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constructor(private readonly io: Apple2IO) {}
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public doLoadLocalTape(file: File, done?: () => void) {
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const kHz = this.io.getKHz();
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// Audio Buffer Source
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let context: AudioContext;
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if (AudioContext) {
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context = new AudioContext();
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} else {
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window.alert('Not supported by your browser');
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done && done();
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return;
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}
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const fileReader = new FileReader();
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fileReader.onload = (ev: ProgressEvent) => {
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const target: FileReader = ev.target as FileReader;
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const result: ArrayBuffer = target.result as ArrayBuffer;
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context.decodeAudioData(result).then((buffer) => {
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const buf: TapeData = [];
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const data = buffer.getChannelData(0);
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let datum = data[0];
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let old = (datum > 0.0), current;
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let last = 0;
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let delta: number;
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debug('Sample Count: ' + data.length);
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debug('Sample rate: ' + buffer.sampleRate);
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for (let idx = 1; idx < data.length; idx++) {
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datum = data[idx];
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if ((datum > 0.1) || (datum < -0.1)) {
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current = (datum > 0.0);
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if (current != old) {
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delta = idx - last;
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if (delta > 2000000) {
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delta = 2000000;
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}
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let ival = delta / buffer.sampleRate * 1000;
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if (ival >= 0.550 && ival < 0.750) {
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ival = 0.650; // Header
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} else if (ival >= 0.175 && ival < 0.225) {
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ival = 0.200; // sync 1
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} else if (ival >= 0.225 && ival < 0.275) {
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ival = 0.250; // 0 / sync 2
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} else if (ival >= 0.450 && ival < 0.550) {
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ival = 0.500; // 1
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} else {
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// debug(idx + ' ' + buf.length + ' ' + ival);
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}
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buf.push([ival * kHz, current]);
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old = current;
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last = idx;
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}
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}
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}
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this.io.setTape(buf);
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if (done) {
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done();
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}
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}, function (error) {
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window.alert(error.message);
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});
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};
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fileReader.readAsArrayBuffer(file);
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}
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}
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