54 lines
1.7 KiB
TypeScript
54 lines
1.7 KiB
TypeScript
// parses VTT timestamp (mm:ss.ms or hh:mm:ss.ms) to seconds
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export const parseVttTime = (raw: string): number => {
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const parts = raw.trim().split(":");
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if (parts.length < 2) return 0;
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const secPart = parts.pop()!;
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const minPart = parts.pop()!;
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const hourPart = parts.pop() ?? "0";
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return Number(hourPart) * 3600 + Number(minPart) * 60 + Number(secPart.replace(",", "."));
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};
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// parses a single VTT cue: timestamp line + text lines
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export const parseVttCue = (line: string, lines: string[], i: number) => {
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if (!line.includes("-->")) return null;
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const [startRaw, endRaw] = line.split("-->");
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const payload: string[] = [];
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let j = i + 1;
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// collect text until blank line
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while (j < lines.length && lines[j].trim() !== "") {
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payload.push(lines[j]);
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j++;
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}
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// strip tags, join lines
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const text = payload
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.join("\n")
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.replace(/<[^>]+>/g, "")
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.trim();
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if (!text) return null;
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return { start: parseVttTime(startRaw), end: parseVttTime(endRaw), text };
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};
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/**
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* Parses full VTT file into cue array.
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* Handles both compact (timestamp on separate line) and standard formats.
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*/
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export const parseVtt = (text: string) => {
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const lines = text.replace(/\r/g, "").split("\n");
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const cues = [];
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for (let i = 0; i < lines.length; i++) {
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const line = lines[i].trim();
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if (!line) continue;
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// compact: cue id on line i, timestamp on i+1
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if (i + 1 < lines.length && !line.includes("-->") && lines[i + 1].includes("-->")) {
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const cue = parseVttCue(lines[i + 1].trim(), lines, i + 1);
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if (cue) cues.push(cue);
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i++;
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} else if (line.includes("-->")) {
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// standard: timestamp on same line
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const cue = parseVttCue(line, lines, i);
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if (cue) cues.push(cue);
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}
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}
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return cues;
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};
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