97 lines
2.9 KiB
TypeScript
97 lines
2.9 KiB
TypeScript
import { fixLineBreaks } from './vttparser';
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import type { CaptionScreen, Row } from './cea-608-parser';
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import { generateCueId } from './webvtt-parser';
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import { addCueToTrack } from './texttrack-utils';
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const WHITESPACE_CHAR = /\s/;
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export interface CuesInterface {
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newCue(
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track: TextTrack | null,
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startTime: number,
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endTime: number,
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captionScreen: CaptionScreen,
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): VTTCue[];
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}
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const Cues: CuesInterface = {
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newCue(
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track: TextTrack | null,
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startTime: number,
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endTime: number,
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captionScreen: CaptionScreen,
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): VTTCue[] {
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const result: VTTCue[] = [];
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let row: Row;
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// the type data states this is VTTCue, but it can potentially be a TextTrackCue on old browsers
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let cue: VTTCue;
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let indenting: boolean;
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let indent: number;
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let text: string;
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const Cue = (self.VTTCue || self.TextTrackCue) as any;
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for (let r = 0; r < captionScreen.rows.length; r++) {
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row = captionScreen.rows[r];
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indenting = true;
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indent = 0;
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text = '';
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if (!row.isEmpty()) {
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for (let c = 0; c < row.chars.length; c++) {
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if (WHITESPACE_CHAR.test(row.chars[c].uchar) && indenting) {
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indent++;
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} else {
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text += row.chars[c].uchar;
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indenting = false;
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}
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}
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// To be used for cleaning-up orphaned roll-up captions
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row.cueStartTime = startTime;
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// Give a slight bump to the endTime if it's equal to startTime to avoid a SyntaxError in IE
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if (startTime === endTime) {
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endTime += 0.0001;
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}
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if (indent >= 16) {
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indent--;
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} else {
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indent++;
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}
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const cueText = fixLineBreaks(text.trim());
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const id = generateCueId(startTime, endTime, cueText);
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// If this cue already exists in the track do not push it
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if (!track?.cues?.getCueById(id)) {
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cue = new Cue(startTime, endTime, cueText);
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cue.id = id;
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cue.line = r + 1;
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cue.align = 'left';
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// Clamp the position between 10 and 80 percent (CEA-608 PAC indent code)
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// https://dvcs.w3.org/hg/text-tracks/raw-file/default/608toVTT/608toVTT.html#positioning-in-cea-608
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// Firefox throws an exception and captions break with out of bounds 0-100 values
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cue.position = 10 + Math.min(80, Math.floor((indent * 8) / 32) * 10);
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result.push(cue);
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}
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}
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}
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if (track && result.length) {
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// Sort bottom cues in reverse order so that they render in line order when overlapping in Chrome
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result.sort((cueA, cueB) => {
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if (cueA.line === 'auto' || cueB.line === 'auto') {
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return 0;
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}
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if (cueA.line > 8 && cueB.line > 8) {
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return cueB.line - cueA.line;
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}
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return cueA.line - cueB.line;
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});
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result.forEach((cue) => addCueToTrack(track, cue));
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}
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return result;
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},
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};
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export default Cues;
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