For macOS · Runs on your Mac

Watch the lecture.Skip the rest.

Paste a YouTube lecture. BriefLectures reads it, finds the logistics, the filler and the parts that repeat, and the player jumps past them while you watch.

Download for Mac See how it works

Free. Apple Silicon, macOS 12 or later. No account.

youtube.com/watch?v=… · Calculus I, Lecture 7: The chain rule Cut the filler

Skipped 0:42 of adminWatch it

0:00 / 1:12:40 Core Example Recap Skipped

An illustration with example numbers. How much a real lecture shrinks depends on the lecture.

EnglishToday we'll look at the chain rule. Hindiआज हम chain rule समझेंगे। SpanishHoy vamos a estudiar la regla de la cadena. Japanese今日は連鎖律について勉強します。 HinglishToh aaj ka topic hai chain rule, samjhe? FrenchAujourd'hui, nous étudions la dérivation en chaîne. Chinese今天我们学习链式法则。 GermanHeute lernen wir die Kettenregel. Tamilஇன்று நாம் சங்கிலி விதியைப் படிப்போம். Arabicاليوم سندرس قاعدة السلسلة.

Three steps, and only the first one is yours.

The lecture opens about a second after you paste the link. The AI works through it from the start, ahead of where you're watching.

1 · Paste

Paste a YouTube link

Any lecture, any length. Watch, youtu.be, shorts and live links all work.

youtu.be/_A6PArXHqUo

2 · Read

It reads the lecture

It uses YouTube's captions in whatever language they're in. No captions? It listens to the audio and writes them on your Mac.

captions · Hindi (auto-generated)

3 · Watch

Watch the short version

The player skips what your cut leaves out. If it skipped something you wanted, one click plays it.

Skipped 0:42 of admin · Watch it

What gets cut

Every 20 seconds of the lecture gets a label. These are the ones a cut can skip. Explanations, examples and recaps stay.

Logistics Can everyone see my screen? Give me one second.

Mic checks, attendance, waiting for the room, homework reminders.

Repeat So again, just to say it one more time…

The same idea explained again, with nothing new added. It's checked against everything said earlier in the lecture.

Filler Um, okay, so, where was I. Right.

Stalling and setup chatter, in any language.

Tangents and promos Before we start, don't forget to subscribe.

Off-topic stories, sponsor reads and channel plugs. Silence is skipped too.

Core explanations stay Worked examples stay Recaps stay, except in Key moments

Pick how short

Switching cuts is instant. Nothing gets re-analyzed. Here's an example 72-minute lecture.

Cut	What it plays	Length
Full lecture	Everything, untouched	72 min
Cut the filler	Skips logistics, filler, repeats, promos and silence	55 min
Key moments	Only the most important explanations	21 min
Custom length	You set a target; it keeps what matters most	30 min

Any language, including the ones you mix.

Captions are read as spoken, without translating them first. A lecture that switches between Hindi and English mid-sentence is followed as it switches.

Transcript · Hindi and EnglishLabel

0:12Sab log mujhe sun pa rahe ho? Ek second, screen share karta hoon.Logistics

0:41आज का topic है chain rule। जब function के अंदर function हो, तब इसका use करते हैं।Core

1:05Example लेते हैं: sin(x²) का derivative निकालते हैं।Example

3:30Matlab, jaise maine bola, phir se bata deta hoon…Repeat

With captions

Opens in about a second, in the captions' own language.

any language

Without captions

Whisper turns the speech into text on your Mac, checking the language every 30 seconds.

~99 languages

The right script

Hindi in Devanagari, Chinese in Simplified characters.

checked every build

Titles and summary

In English, or in the lecture's own language. Your choice in Settings.

your choice

Private by design

The AI runs on your Mac.

BriefLectures uses a local model through Ollama, a free app. What you watch isn't uploaded anywhere, and there's no account to make. Results are saved on your Mac, so each lecture is only analyzed once.

Modelqwen3.5:4b

Download3.4 GB

Memory while working~4.5 GB

AccountNone

Questions

Short answers. The longer ones are in the project's docs.

Which Macs does it run on?

Apple Silicon Macs (M1 or newer) on macOS 12 or later. It's sized for 16 GB of memory: the AI model uses about 4.5 GB while it works, and it's unloaded a couple of minutes after.

Do I have to wait for the analysis?

No. The lecture opens about a second after you paste the link, with quick skips for silence and logistics. The AI then works through the lecture from the start, ahead of where you're watching, and its skips switch on part by part.

What if it skips something I needed?

Every skip shows a small "Watch it" button that jumps back and plays that part. You can also turn auto-skip off, or switch to the full lecture at any time.

What about videos with no captions?

It downloads the audio and transcribes it on your Mac with Whisper. This is slower than reading captions, and only happens once per video.

Why do I need Ollama?

Ollama runs the AI model on your Mac. It's free, and BriefLectures walks you through installing it and downloading the model the first time you open it. Without it, you still get a rough offline estimate.

Is it free?

Yes. There's no account and no subscription. Everything runs on your own Mac.

Your next lecture, minus the rest.

Download for Mac Free · Apple Silicon · macOS 12 or later