Youtube Transcripts

YouTube Channel Transcripts

Downloads English auto-caption transcripts for a channel's videos in a given date range and leaves one markdown file per video, with frontmatter linking it back to the source video. Lines are timestamped by default; --no-timestamps drops the times and leaves the prose.

Requirements

yt-dlp and ffmpeg must be on PATH.

yt-dlp --version && ffmpeg -version | head -1

If missing on macOS: brew install yt-dlp ffmpeg.

Parameters

• channel_url (required) — channel URL, e.g. https://www.youtube.com/@AIDailyBrief/videos. The /videos suffix is added automatically if absent.
• start — inclusive start date, YYYYMMDD. Defaults to 7 days ago.
• end — inclusive end date, YYYYMMDD. Defaults to today.
• max (optional) — cap on number of transcripts.
• --no-timestamps (optional flag, goes first) — omit the [HH:MM:SS] prefixes. Still markdown, still with the same frontmatter; only the per-line times go away.
• --chunk N (optional flag, goes first) — group the text into ~N-second paragraphs instead of one line per caption line. --chunk 30 reads well as prose; the default is better for grepping and citing exact moments. Combines with --no-timestamps for plain paragraphs.

Timestamps are the default — don't pass a flag for them. Output is always .md, and the intermediate .srt is never left behind.

Ask the user for the channel URL if it isn't given.

If the request has no date range, ask for one before running. An active channel can have thousands of videos, and a request that doesn't mention dates is far more likely to be an oversight than a request for the entire back catalog. Offer the last 7 days as the default and let the user widen it. Only skip the question when the user has already stated a range, said something like "everything" or "all of it", or already declined to narrow it.

Convert natural-language ranges yourself ("July 2026" → 20260701 20260731, "last month", "since May"). Look up today's date rather than assuming it.

The script applies the same 7-day default on its own if dates are omitted, so a forgotten range can't turn into a full-catalog download — but ask first rather than relying on that.

Usage

scripts/fetch_transcripts.sh [--no-timestamps] [--chunk N] <channel_url> [start_YYYYMMDD] [end_YYYYMMDD] [max]

Omitting the dates fetches the last 7 days and says so.

Example — all July 2026 videos from AI Daily Brief, as timestamped markdown:

scripts/fetch_transcripts.sh "https://www.youtube.com/@AIDailyBrief/videos" 20260701 20260731

Example — at most 5 transcripts:

scripts/fetch_transcripts.sh "https://www.youtube.com/@AIDailyBrief/videos" 20260701 20260731 5

Example — timestamps grouped into 30-second paragraphs:

scripts/fetch_transcripts.sh --chunk 30 "https://www.youtube.com/@AIDailyBrief/videos" 20260701 20260731

Example — prose without timestamps:

scripts/fetch_transcripts.sh --no-timestamps "https://www.youtube.com/@AIDailyBrief/videos" 20260701 20260731

Output lands in the current directory as YYYYMMDD - Title [VIDEOID].md. The video ID is kept in the filename so a transcript can always be traced back to its source, and every file carries it in YAML frontmatter regardless of mode:

---
title: Is Kimi K3 Really Fable Class
date: 20260721
video_id: lmQqiWQF_8I
url: https://www.youtube.com/watch?v=lmQqiWQF_8I
---

# Is Kimi K3 Really Fable Class

Link to any moment: `https://www.youtube.com/watch?v=lmQqiWQF_8I&t=<seconds>s`

[00:00:00] Today on the AI Daily Brief, did we
[00:00:02] actually just get a fable level open

With --chunk 30, one paragraph per 30 seconds instead of one line per caption line. With --no-timestamps, the same file minus the [HH:MM:SS] prefixes and the deep-link hint — the frontmatter is unchanged.

To deep-link a quote, convert its [HH:MM:SS] to seconds and append &t=<seconds>s to the url from the frontmatter — no lookup or web search needed.

How it works

• Channels list newest-first, so the script uses --break-match-filters on the start date to stop walking the catalog once it passes below the range — it does not scan all videos.
• --sub-langs en (not en.*) avoids downloading both en and en-orig, which are duplicates on most channels.
• --sub-format ttml is what keeps the output clean. YouTube serves auto-captions in several formats; the default vtt/srt ones are a rolling two-line window where each cue repeats the previous line above the new one (interleaved with 10 ms "hold" cues), so every phrase lands in the file about twice. ttml has one entry per phrase with no repetition, and --convert-subs srt turns it into a plain SRT. Requesting the right format beats deduplicating afterward — a transcript is allowed to contain genuinely repeated lines.
• The ttml → srt conversion wraps each line in <font …> styling tags; both output paths strip them.
• scripts/srt_to_md.awk does the .md formatting: it drops index and timestamp lines and re-tags each caption line with its start time as [HH:MM:SS].

Notes

• yt-dlp exits non-zero when --break-match-filters or --max-downloads trips; the script treats those as normal completion.
• If a video has no English auto-captions it's silently skipped.
• The script takes a snapshot of the directory before fetching, and only files that appear afterward are converted or cleaned up. Anything already present is counted, reported, and left untouched, whatever it's named — so running twice in the same directory can't mangle or delete the first run's output.
• This skill is YouTube-only by design. --sub-format ttml relies on YouTube offering that format, which it does for every video and language; other sites may not, in which case the fetch would find no matching subtitle format.