AudioPull
Turn Lecture Recordings into Study Audio You Can Take Anywhere
Recorded lectures are one of the best study resources you have — and one of the least used. The recordings pile up: hour-plus videos, gigabytes each, that you can only realistically watch sitting down with your phone or laptop open. Between commutes, gym sessions, walks and chores, most students have far more listening time in a week than watching time. Converting lecture videos to audio unlocks all of it.
Why audio-first revision works
Most of a lecture's value is in the speech. Unless the class is heavily visual — anatomy diagrams, code walkthroughs, worked equations — the slides mostly restate what the lecturer says. Turning the video into audio keeps the substance while changing where and how you can use it:
- Repetition becomes cheap. Spaced re-exposure to material is one of the most reliable ways to strengthen memory, but nobody re-watches a one-hour video three times. Re-listening during dead time — commuting, cooking, walking between classes — costs nothing.
- Screen-off listening. An audio file plays like a podcast: background playback, lock-screen controls, headphones. A video in many apps demands an open, unlocked screen.
- Storage stops being a problem. The video stream is typically over 90% of a recording's size. A semester of lectures that would swamp an iPhone as video fits comfortably as audio.
- Focus, oddly, can improve. Without slides to passively stare at, your brain has to reconstruct the argument — a form of active recall in itself.
What you need before you start
Two ingredients: the recordings themselves, saved on your iPhone (in your photo library or the Files app), and an extractor that runs on-device. Make sure you're allowed to keep and convert the recordings — most universities permit personal study use of lecture captures, but check your institution's policy, and don't redistribute converted files.
A note on tooling: online converter sites are a poor match for lecture work. Uploading a 1.5 GB video over campus Wi-Fi, waiting for a remote server, then downloading the result — repeated for every lecture — is exactly the friction that makes people give up. An offline app converts straight from the library at the speed of your phone, with nothing uploaded anywhere (more on that in our privacy guide).
Choosing the right settings for speech
Lectures are speech, and speech is easy to compress well. AAC — the codec inside M4A files — is particularly good at keeping voices crisp at modest bitrates. For a full comparison see M4A vs MP3 explained, but the short version for lectures:
- 128k AAC is the workhorse: clear, articulate speech at roughly 58 MB per hour.
- 192k if the recording includes audience questions, demonstrations or music and you want headroom.
- 256k–320k is rarely necessary for talking-head lectures — but harmless if storage is no object.
A batch workflow for a whole course
Converting one lecture is trivial; the real win is doing a backlog in one sitting. This is where batch processing earns its keep. A sensible end-of-week (or end-of-semester) routine looks like this:
- Gather. Make sure the week's recordings are saved to your photo library or Files.
- Queue. Select all of them in your extractor at once rather than one by one. In AudioPull you can queue multiple videos for extraction and preview each one first to confirm it's the right file.
- Convert in the background. Let the queue run while you do something else — AudioPull processes videos in the background and shows individual and overall progress in real time, and failed items can be skipped or retried instead of silently vanishing.
- Organize and back up. Extracted files sit in organized storage with metadata and a full history, and are accessible through the Files app — from there, copy them into a per-course folder or your cloud drive. Automatic duplicate detection means re-running the queue won't litter your library with copies.
Tip: convert recordings soon after each lecture rather than in an end-of-term panic. A five-minute weekly habit produces a complete, ready-to-review audio archive exactly when exams arrive.
Making the audio work harder for you
Once lectures live as audio files, they slot into any podcast-style routine: queue the week's material for a long trip, re-listen to the toughest lecture the night before a seminar, or skim your own recorded presentations to hear how you actually sound. Pair passive listening with active methods — after a re-listen, write down the three key claims from memory, then check. The audio file is the raw material; the recall practice is what turns it into marks.
Beyond lectures
The same workflow covers everything else on the academic calendar: conference talks you filmed, thesis-defence recordings, guest speaker sessions, language-class dialogues, and interviews recorded for research projects. Anything that exists as video with valuable speech inside is a candidate.
How AudioPull helps
AudioPull is a free iPhone and iPad app built for precisely this job: it extracts audio from recorded lectures and presentations, supports major formats like MP4, MOV and AVI, exports M4A (AAC) at 128k–320k, batch-processes whole queues in the background, and works entirely offline so recordings never leave your device. Download it free on the App Store and turn your backlog into a study library this week.