Compress a recording to a real upload limit

Record the actual byte size and duration. Ask whether the destination limit is expressed in decimal MB or another unit, and whether audio is included. Leave room for container overhead rather than aiming at the exact boundary.

For an illustrative 90-second recording with a 20 MB decimal limit, 20,000,000 × 8 ÷ 90 is about 1.78 megabits per second for the entire file. That is a rough total-rate budget, not an instruction to set video alone to 1.78 Mbps or a guarantee of exact export size.

Trim an empty lead-in, a failed attempt and an unnecessary ending if the editor supports it. Preserve the steps and result. Cutting thirty seconds of dead time may solve a size problem without sacrificing text detail across the whole lesson.

Keep the original before editing. Watch the join after each cut: a smaller file is not useful if the viewer misses the menu choice that explains the next screen. Do not speed every action simply to reduce duration.

Use a supported editor and change one meaningful export setting at a time. Apple’s QuickTime export guide offers lower-resolution choices and different codec options; availability depends on the source. Its output movie format is .mov, so check the destination’s accepted formats separately.

Compare the new file’s actual size rather than promising that halving dimensions halves bytes. Content motion, encoding choices, audio and duration all influence the result. A static slide and fast gameplay need not compress in the same way.

Select three details to inspect: a menu item, a numeric result and a moving selection. Play the compressed copy at the recipient’s viewing size. If those fail, enlarge the relevant interface and recapture, split the lesson or choose a better delivery method.

Do not repeatedly re-encode the last compressed copy. Return to the preserved original for another trial. This keeps the comparison understandable and avoids an unnecessary chain of quality-changing exports.

Upload the acceptable candidate and inspect the processed rendition. Confirm sound, aspect ratio, duration and the reading test. A platform can process your upload, so the local export is not the final evidence of what the viewer receives.

If no acceptable copy fits, send a shorter task-specific clip or use an authorised file-transfer route with a suitable limit. State the trade-off honestly. There is no universal “smallest” recording setting that preserves every interface.