youtube-captions

Extract timestamped captions from YouTube videos. Output is VTT format (timestamps preserved).

Prerequisites

• yt-dlp — REQUIRED (brew install yt-dlp)
• openai-whisper — REQUIRED only if video has no subtitles (pip install openai-whisper)
  • First run downloads the small model (~500MB)
  • Transcription is significantly slower than subtitle download

Usage

bash scripts/get-captions.sh <youtube-url> [language]

• youtube-url — any valid YouTube video URL
• language — subtitle language code (default: en)

Output goes to stdout. Status messages go to stderr.

Fallback Chain

1. Manual subtitles — human-uploaded captions (fastest, most accurate)
2. Auto-generated subtitles — YouTube's speech recognition
3. Whisper transcription — downloads audio, transcribes locally with whisper --model small

The script tries each step in order and exits on the first success.

Example

# Get English captions
bash scripts/get-captions.sh "https://www.youtube.com/watch?v=dQw4w9WgXcQ"

# Get Spanish captions
bash scripts/get-captions.sh "https://www.youtube.com/watch?v=dQw4w9WgXcQ" es

Output Format

VTT (Web Video Text Tracks) with timestamps:

WEBVTT

00:00:01.000 --> 00:00:04.000
First line of dialogue

00:00:04.000 --> 00:00:08.000
Second line of dialogue

Notes

• All temporary files (audio, intermediate subtitle files) are cleaned up automatically
• If neither yt-dlp subtitles nor Whisper are available, the script exits with an error and clear instructions
• Long videos with no subtitles will take time to transcribe — Whisper processes roughly at 1x realtime on CPU