94 lines
1.9 KiB
TypeScript
94 lines
1.9 KiB
TypeScript
// SPDX-License-Identifier: MIT
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/**
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* @param {string} data SRT text to be converted
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* @returns {string} VTT text
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*/
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export default function srt2webvtt(data: string): string {
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// remove dos newlines
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let srt = data.replace(/\r+/g, "");
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// trim white space start and end
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srt = srt.replace(/^\s+|\s+$/g, "");
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// get cues
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const cuelist = srt.split("\n\n");
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let result = "";
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if (cuelist.length > 0) {
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result += "WEBVTT\n\n";
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for (let i = 0; i < cuelist.length; i = i + 1) {
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result += convertSrtCue(cuelist[i]);
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}
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}
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return result;
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}
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/**
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* @param {string} caption SRT section for parsing
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* @returns {string} translated VTT section
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*/
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function convertSrtCue(caption: string): string {
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// remove all html tags for security reasons
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//srt = srt.replace(/<[a-zA-Z\/][^>]*>/g, '');
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let cue = "";
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const s = caption.split(/\n/);
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// concatenate muilt-line string separated in array into one
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while (s.length > 3) {
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for (let i = 3; i < s.length; i++) {
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s[2] += "\n" + s[i];
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}
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s.splice(3, s.length - 3);
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}
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let line = 0;
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// detect identifier
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if (!s[0].match(/\d+:\d+:\d+/) && s[1].match(/\d+:\d+:\d+/)) {
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cue += s[0].match(/\w+/) + "\n";
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line += 1;
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}
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// get time strings
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if (s[line].match(/\d+:\d+:\d+/)) {
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// convert time string
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const m = s[1].match(
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/(\d+):(\d+):(\d+)(?:,(\d+))?\s*--?>\s*(\d+):(\d+):(\d+)(?:,(\d+))?/,
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);
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if (m) {
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cue += m[1] +
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":" +
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m[2] +
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":" +
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m[3] +
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"." +
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m[4] +
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" --> " +
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m[5] +
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":" +
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m[6] +
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":" +
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m[7] +
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"." +
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m[8] +
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"\n";
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line += 1;
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} else {
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// Unrecognized timestring
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return "";
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}
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} else {
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// file format error or comment lines
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return "";
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}
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// get cue text
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if (s[line]) {
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cue += s[line] + "\n\n";
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}
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return cue;
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}
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