Get YouTube Video Transcript
Returns the timed transcript (subtitles) of a YouTube video by its 11-character `videoId`. `languageCode` selects the track (e.g. `en`, `de-DE`, `pt-BR`); `type=asr` requests the auto-generated speech-recognition track. Each segment in `transcript[]` carries `startMs`, `endMs`, `snippet`, and a formatted `startTimeText`. The response also includes `availableTranscripts[]` listing every track on the video (language name + code, `type: asr` for auto-generated, `selected: true` for the one returned) so callers can discover what else is available. Use to feed a video's spoken content into RAG/LLM pipelines, generate summaries or chapter outlines, build searchable archives, run translation or accessibility workflows, or analyze talking points across a creator's catalog (pair with the YouTube Channel endpoint to enumerate videos, then fetch transcripts).