AI Lecture Notes: Chat with Hours of Video Content
You have 12 hours of lecture videos from this semester, exams are in two weeks, and you can’t remember which lecture covered the topic you need. Scrubbing through video is slow. Manual note-taking is incomplete. With LocalRAG! v3.0, just ask: “Which lecture explained eigenvalues?” and jump to the exact 30-second segment. All on your phone or tablet, no cloud upload required.
The lecture video problem
Recorded lectures are gold mines of knowledge that no one mines. Watching them at 2x speed is faster than the original but still slow. Manual notes miss things; instructor-provided slides lack the explanations. Cloud services that transcribe and summarize lectures exist, but uploading hours of video raises privacy concerns — your video might contain other students’ voices, exam hints, or institution-sensitive material. Many universities prohibit uploading lecture recordings to third-party services entirely.
How LocalRAG! solves this
LocalRAG! extracts audio from MP4/MOV/M4V video files and transcribes it on your device using WhisperKit. The transcript is automatically segmented with timestamps and indexed for AI Q&A. Ask the AI to explain concepts, find specific topics, compare what different lectures said about the same subject, or summarize an entire course — all without uploading a single video to any server.
Import your lecture videos
Drop MP4, MOV, or M4V files into LocalRAG!. Multiple lectures can be organized into a Collection (e.g., “Math 201 Spring 2026”).
On-device transcription
WhisperKit extracts audio and transcribes with word-level timestamps. AI cleanup removes fillers. A 60-min lecture takes ~10 min to process on iPhone 17 Pro.
Study with AI
Ask “Explain how eigenvalues relate to matrices, with the lecture timestamp.” Tap citations to jump to that moment in the video.
Why use LocalRAG! for lecture videos
Cross-lecture search
Search across an entire semester’s worth of lectures in one Collection. “When did we cover Bayes’ theorem?” returns hits from any lecture that mentioned it.
Jump-to-timestamp
Tap any AI citation to scrub directly to that moment in the original video. No more guessing which 5-minute segment you need.
Multi-language lectures
Whisper handles 99+ languages including English, Japanese, Mandarin, French, German, Spanish, and more. Ask in your native language about a lecture in another.
Combine with reading materials
Mix lecture videos with PDFs, slides, and your typed notes in one Collection. AI searches across video transcripts and text together.
Example questions you can ask
“When did the professor first introduce Fourier transforms?”
LocalRAG! finds the lecture and exact timestamp where the topic is first introduced, with the explanation in context.
“Explain Bayes’ theorem using the example from lecture 5”
Retrieves the example from lecture 5’s transcript and rephrases it as a clear explanation.
“What are the prerequisites for the next exam topic?”
Scans across lectures to identify prerequisite topics mentioned by the instructor.
“Did the professor say anything about exam format?”
Searches all lectures for exam-related comments and returns timestamps for verification.
Verdict
Your lecture videos shouldn’t sit unwatched in a folder. LocalRAG! v3.0 turns them into searchable, queryable study material — on your phone, with complete privacy. Whether you’re cramming for finals or revisiting a concept months later, the answer is one question away.
FAQ
What video formats are supported?
MP4, MOV, and M4V. LocalRAG! extracts the audio track on-device using AVFoundation (iOS) or MediaExtractor (Android), then transcribes with WhisperKit/whisper.cpp.
Can I import lectures from YouTube?
LocalRAG! doesn’t download from YouTube directly (against ToS), but if you have a local recording of a lecture (recorded with permission), you can import the MP4 file. Many universities provide downloadable recordings.
How accurate is the transcription for technical lectures?
WhisperKit base model handles general speech ~85% accurately. Technical jargon and proper nouns can be imperfect; the LLM cleanup pass helps recover meaning. v3.1 will offer Whisper small/medium for higher accuracy on technical content.
Try LocalRAG! Free
Free tier with 5 questions per day. No account required.