YouTube summaries with timestamps: a real video test
What VideoOutline produced during a real preview test, how timestamp navigation works, and what the results do not establish.
Last updated: 2026-11-09
VideoOutline helps readers navigate a YouTube lesson with an overview, key points and timestamp links. The evidence below comes from our own preview tests, not an independent benchmark. Caption retrieval and full summary generation were checked separately.
The video and the test
On 7 November 2026, we tested the installed VideoOutline preview extension with Andrej Karpathy's Let's build GPT video, a 116-minute programming lesson. The recorded run returned an English overview and seven explanations covering topics including data preparation, bigrams, attention, training and RLHF. Processing used the video fallback because caption retrieval failed in that run.
What the result is useful for
The overview provides a starting point for deciding which parts to study. The topic coverage helps locate relevant ideas, but does not prove that every explanation is accurate. This page describes our recorded test; it is not a verbatim reproduction of the model output or a full transcript.
Returning to the source
The same test session verified that clicking a summary timestamp moved a video player to 150 seconds. For a simple demonstration of a timestamp link, open the programming lesson at 02:30. This link illustrates navigation only; it is not presented as the source of a specific generated claim.
What we verified and what we did not
The long-video run took 35 seconds in that observation. That is a single measurement, not an average, speed promise or service guarantee. We verified a visible summary and broad topic coverage; we did not audit every sentence against the full video. Only the first point in that run had a separate title, so consistent formatting remained an improvement area.
On 8 November, separate caption retrieval checks succeeded for one English and one Chinese video after a fallback fix. Those checks measured caption retrieval, not full summary accuracy or end-to-end speed. They do not establish support for every YouTube video.
Try the workflow
VideoOutline is available on the Chrome Web Store; generation requires an active trial or subscription. Start with the step-by-step guide, check the installation requirements, or read how to take lecture notes. Always return to the original video before relying on an important claim.
Evidence at a glance
| Check | Recorded observation | What it establishes |
|---|---|---|
| 116:20 programming lesson, 7 Nov 2026 | Overview and seven explanations; 35 seconds in one run | A long-video summary was returned in that run, not an average processing time |
| 65:25 interview, 7 Nov 2026 | No caption track exposed; video fallback returned a Chinese overview and six titled points | One successful fallback, not universal no-caption support |
| Timestamp navigation, 7 Nov 2026 | Clicking a summary timestamp moved the player to 150 seconds | Navigation worked; claim accuracy was not fully audited |
| English caption retrieval, 8 Nov 2026 | 427 segments retrieved for a 20:03 video | Caption collection worked in this check, not a new summary accuracy test |
The interview sample was this recorded interview; the English caption sample was Sir Ken Robinson's TED talk. Results were recorded by the VideoOutline team. No claim of independent certification is made.