Skip to main content
Thirdwatchthirdwatch
Social media

Audit Which YouTube Videos Only Have Auto-Generated Captions

Check at scale whether videos ship human-written captions or only YouTube's auto-generated ASR track — an accessibility and content-quality audit.

Sep 16, 2026 · 3 min read · 591 words
See the scraper →

Auto-captions exist almost everywhere — the question is whether a human ever wrote real ones. Thirdwatch's YouTube Subtitle Scraper returns every caption track a video offers as timestamped segments plus full video metadata — no API key, no OAuth.

Skip the setup: Run this as a ready-to-go task on Apify — pre-loaded with the configuration from this guide.

Why audit caption coverage

Auto-generated captions are better than nothing, but they mangle names, jargon and anything spoken over music. For a channel audit or accessibility review you need to know which videos have a real caption track and which are ASR-only — and nothing on the watch page reports that at scale.

The Actor labels every returned track manual or auto via captionSource and reports the full availableLanguages list, turning an hours-long manual audit into one run.

The subtitle scraper reads the public caption endpoints directly, so the batch path is a list of URLs in and transcript rows out.

How does this compare to the alternatives?

Approach Cost model Coverage Effort
YouTube Data API + OAuth Quota-limited, free tier Only authorised captions / own channel Key + OAuth setup
Manual transcript-panel copy Analyst hours One video at a time Doesn't scale
Thirdwatch YouTube Subtitle Scraper Pay per video row All public caption tracks Zero setup

Why this Actor

  • Manual and auto-generated tracks both supported — captionSource labels which you got.
  • Every segment carries startMs, durationMs and text, so timestamp-level alignment survives.
  • availableLanguages lists every track the video offers — discovery and extraction in one pass.
  • Each video gets its own proxy session with a fresh-exit retry, so multi-video batches stay reliable.
  • Full metadata on the row: title, channel, duration, view count, upload date.

How to do it in 3 steps

Step 1: Configure the input

Set the inputs as shown below — videoUrls takes the targets, languages picks the caption language(s) and preferManual chooses human-written over auto-generated tracks.

Step 2: Run the Actor

Run it from the console, the API, or the linked saved task. One dataset row is written per video.

Step 3: Use the output

Each row carries the video metadata, the caption track as segments (with startMs/durationMs/text), and the joined transcript string.

{
  "videoUrls": [
    "https://www.youtube.com/watch?v=dQw4w9WgXcQ"
  ],
  "languages": [
    "en"
  ],
  "preferManual": false,
  "proxyCountry": "US"
}

Each dataset row looks like:

{
  "videoId": "dQw4w9WgXcQ",
  "url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
  "title": "Rick Astley - Never Gonna Give You Up (Official Video)",
  "channel": "Rick Astley",
  "language": "en",
  "captionSource": "manual",
  "segmentCount": 61,
  "segments": [
    {
      "startMs": 18170,
      "durationMs": 2290,
      "text": "We're no strangers to love"
    }
  ],
  "transcript": "We're no strangers to love ..."
}

What to watch for

Heavily scraped videos sometimes return a 429 on the caption file even after the fresh-exit retry — those come back as error rows, not silent gaps. Videos with no captions at all behave the same way, which is itself a useful audit signal.

Related use cases

Run the YouTube Subtitle Scraper on Apify Store — pay per result, free to try, no credit card to test.

Frequently asked questions

Do I need a YouTube API key?

No — the Actor reads the public caption endpoints, so there is nothing to provision.

What languages work?

Any language the video ships a track for. Pass ISO 639-1 codes in `languages`, or omit it and read `availableLanguages` on the row to see what exists.

Auto captions or human captions?

Both are supported. `preferManual` prefers human-written tracks; `captionSource` on the row tells you which type was actually returned.

Why did one video return an error row?

Heavily scraped videos occasionally hit a caption-side rate limit. The Actor retries once on a fresh proxy session; a persistent failure comes back as an `error` row you can retry.

Can I get plain text without timestamps?

Yes — `transcript` is the segments joined into one string. Keep `segments` too if you want timestamp-level retrieval.

How many videos per run?

Dozens comfortably — each video gets an isolated proxy session, so batch size is bounded by run timeout rather than rate limits.

Related

Try it yourself

100 free credits, no credit card.

About 30 real searches. Add the MCP to Claude or Cursor in two minutes.