YouTube Transcript (via yt-dlp)

Fetch a YouTube video's captions (no video download) and save a clean raw .txt transcript.

Save location

• If the user is in a real project/working dir → save there.
• Otherwise (no dir given, or cwd makes no sense) → save to ~/Downloads.

Fastest path

OUT="$(pwd)"            # or ~/Downloads if cwd makes no sense
META=$(yt-dlp --print "%(channel)s|%(title)s" --skip-download "URL")
NAME=$(echo "$META" | tr '| ' '__' | tr -cd '[:alnum:]_.-')   # "Channel_Title", spaces -> _, strip unsafe chars
yt-dlp --skip-download --write-subs --write-auto-subs \
  --sub-langs "en.*" --sub-format json3 \
  -o "$OUT/$NAME.%(ext)s" "URL"

Always name the file Channel_Title with spaces replaced by _ (e.g. David_Ondrej_title_of_video.txt). Fall back channel → uploader → uploader_id if channel is null.

• --skip-download = captions only. --write-subs + --write-auto-subs = manual first, auto as fallback (yt-dlp prefers manual automatically).
• Always use json3, never VTT/SRT — auto VTT repeats every line twice (rolling captions). json3 is clean structured JSON.

Flatten json3 → raw text

python3 - "$OUT" <<'PY'
import json, html, re, glob, sys, pathlib
f = glob.glob(sys.argv[1] + "/*.json3")
if not f: sys.exit("no json3 file")
data = json.load(open(f[0], encoding="utf-8"))
parts = ["".join(s.get("utf8","") for s in e.get("segs") or []) for e in data.get("events", [])]
txt = re.sub(r"\s+", " ", html.unescape(" ".join(p.strip() for p in parts if p.strip()))).strip()
out = pathlib.Path(f[0]).with_suffix(".txt")
out.write_text(txt, encoding="utf-8"); print(out)
PY

Output: <video_id>.txt in the chosen dir. Report the path; print the text if short.

Notes

• Non-English / unknown language: run yt-dlp --list-subs "URL" first, then set --sub-langs.
• Newer yt-dlp may need deno on PATH for YouTube extraction.

Failure handling

• On first failure: run yt-dlp -U once, retry once, then stop.
• 429 / "Sign in to confirm you're not a bot" = IP flagged. STOP — do NOT retry in a loop (makes it worse).
• Empty / "no subtitles" = video has no captions. Report it; don't retry, don't switch tools.
• Never fall back to downloading audio for Whisper unless the user explicitly asks.