TL;DR. A delayed mirror shows the camera feed on a fixed lag, usually 10 to 15 seconds for short skills, so you finish the rep, look up, and watch yourself from the outside, no hands, no operator. It is one of two models for seeing your own training: the continuous delayed feed (every rep replays, nothing kept) and the rolling buffer with triggered saves (ReplayR's model: only flagged reps kept, as clips with slow motion). This page explains both honestly, including when ReplayR is the wrong choice.
The app holds the last N seconds of camera frames in memory and displays them N seconds late. Set a 15 second delay, do a turn, walk two steps to the screen: your turn is just starting to play. There is no record button, no saving, no interaction at all; frames older than the delay window are discarded. The screen is effectively a mirror into the immediate past, which fixes the fundamental problem of real mirrors: you cannot watch yourself mid-jump, mid-turn, or mid-lift, because you are busy doing it.
The right delay is movement duration plus walking time. Short skills sit around 10 to 15 seconds; a full dance phrase needs the phrase length plus about 5 seconds. Our replay delay reference lists per-sport numbers, and the principle from motor learning research holds here too: feedback lands best within about 20 seconds, while the felt attempt is fresh.
Every rep replays automatically on the lag; nothing is kept, nobody operates anything. Best for unattended stations with high rep counts: a barre, a tumbling strip, a PE class rotating through. BaM Video Delay is the established app in this model, with delays from 1 second to 6 minutes. The cost: full camera and screen duty the whole session, and at the end you have nothing to compare, share, or slow down.
The camera records continuously into temporary memory; a tap, Wear OS watch press, or open-palm gesture keeps the last N seconds as an MP4. Best when attempts differ in value: the breakthrough double turn, the lift that moved differently. You end the session with a folder of the reps that mattered, each ready for 0.5× or 0.25× review and peer-to-peer sharing. This is ReplayR's model.
Honest rule: if nobody can trigger a save, not even hands-free, use a continuous delay app. The moment a trigger is possible, the buffer model wins, because kept clips compound: today's attempt against last month's, in slow motion, side by side in your gallery.
Continuous-delay reference app: BaM Video Delay, App Store listing. Last verified 2026-07-19.
Tripod at the mirror's corner, full body in frame, 15 second delay for turns and jumps or phrase length plus 5 seconds for combinations. Dancers glance at the screen as they pass. With ReplayR instead, the open-palm gesture (Pro) saves a phrase without breaking position; see ReplayR for dancers and musicians.
End of the tumbling strip or beside the vault landing mat, 15 to 20 second delay: run-up, skill, landing, walk to the screen. For coached sessions where the coach picks the attempts worth keeping, the watch-triggered buffer replaces the delay screen.
Side-on at hip height. A 20 second delay lets you rack the bar and turn around to watch the set. The buffer model fits lifting better in practice, since sets have clear ends and a wrist trigger is natural; see ReplayR for weightlifting form checks.
An app that shows the camera feed on a fixed lag, typically 5 to 30 seconds, so you finish a movement, look up at the screen, and watch yourself doing it moments ago. Like a mirror, but showing the immediate past instead of the present, which lets you see a jump, a turn, or a lift from the outside without touching anything.
No, and that matters for picking the right tool. ReplayR is replay-on-demand: a rolling buffer records continuously and you trigger a save by tap, watch, or open-palm gesture, keeping the clip as an MP4 with slow motion. A true delayed mirror shows every rep automatically and keeps nothing. For a fully unattended station, use a continuous-delay app like BaM Video Delay; when a save trigger is possible, ReplayR keeps the attempts worth reviewing.
Movement duration plus walking time to the screen. Short skills work well around 10 to 15 seconds: a jump or turn takes 2 to 4 seconds, and the lag leaves time to finish and look up. Longer phrases need the full phrase length plus about 5 seconds. If you reach the screen too early you wait; too late and the rep has already played.
Yes, this is the standard setup: an old phone or tablet on a tripod beside the studio mirror or platform, running a continuous-delay app, plugged into a power bank for sessions past 90 minutes. Athletes glance at it after each rep, nobody operates anything. Many coaches then run ReplayR on their main phone to keep the attempts worth comparing over time.
Rolling buffer, watch or palm-gesture save, slow-motion review. Free, one-time Pro unlock.
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