How to capture instant replay on the sideline with ReplayR
TL;DR. Mount the phone courtside, start ReplayR's rolling buffer (45 s or 90 s free, up to 12 min on Pro), and tap save after every highlight — from the phone, your Wear OS watch, or an open-palm gesture. Saves take 200–500 ms with no re-encoding. At session end, swipe right to keep, left to toss. Nothing leaves the device unless you share it.
Why a rolling buffer beats full-session recording
Full-session recording wastes storage on dead time between plays, drains battery, and forces you to scrub through hours of footage afterwards. A rolling buffer keeps only the last N seconds on disk and discards everything older. You hit save after a great play and get exactly the moment that mattered — no scrubbing, no editing, no 4 GB MP4 to manage.
ReplayR rotates 5-second chunks as temp files. Chunk count = buffer duration ÷ 5 s, so a 90-second buffer holds 18 chunks at any moment. When you save, FFmpeg concatenates them in 200–500 ms, no re-encoding required, and recording resumes within 1 second.
Step-by-step
- 1
Mount the phone courtside
Use a tripod, a fence wedge, or any stable mount with a clear, framed view of the play area. Landscape works best for full-court / full-pitch framing. Keep the lens clean — sideline dust is your enemy.
- 2
Pick the right buffer length
Free: 45 s or 90 s. Pro: 3, 6, or 12 minutes. A tennis or padel point fits in 45 s. A full basketball possession fits in 90 s. A whole soccer attacking phase fits in 3 min. Pick the buffer that covers your longest single capture.
- 3
Set capture resolution
480p (free) is enough for review and most sharing. Pro unlocks 720p, 1080p, 1440p, 4K, and 8K (capped to your device's camera). Higher resolution = larger temp chunks = more storage churn. 1080p is the practical sweet spot for sideline use.
- 4
Start the rolling buffer
Tap Start. ReplayR begins recording 5-second chunks and rotates the oldest out as new ones come in. The buffer timer fills up to your chosen length, then stays full. Only the last buffer length ever lives on disk until you tap save.
- 5
Enable stealth mode for long sessions
Tap the screen-dim icon. The display goes pure-black while the camera keeps rolling — display draw drops to near-zero, useful for sessions over an hour. Tap the screen to bring controls back.
- 6
Save after every highlight
Three save paths: tap on-phone, tap your Wear OS watch (Tile or Complication for one-tap save from the watch face), or trigger the open-palm hand gesture (Pro, with 5-step sensitivity tuning). Save takes 200–500 ms; recording resumes in ~1 s.
- 7
Review at end of session
Tap End session (phone or watch). The Review screen presents each saved clip as a swipe card. Swipe right to keep, left to toss. Trim and adjust speed with the in-app editor. Tossed clips sit in a bin for 24 hours (Pro can restore).
- 8
Export or share
Kept clips export to your phone gallery via the system share sheet. No cloud upload, no account, no watermark. Share to Photos, Messages, WhatsApp, Drive — anywhere your OS supports.
Sideline setup tips
- Keep the phone plugged in for sessions over 90 minutes — buffering is lighter than full-session record but still draws ~10–15% per hour.
- Free up 2 GB of storage before you start. ReplayR rotates temp chunks, but kept clips at 1080p run ~10 MB / 10 s.
- Lock orientation before mounting. A mid-session orientation flip resets the buffer.
- Use the watch save if you're in the play. Tap the wrist between rallies — no walking back to the tripod.
- Open-palm gesture (Pro) is hands-free. Useful in the gym for solo form checks: lift, walk into frame, raise palm.
Further reading
For background on the cognitive value of post-action video review in sport, see the systematic review by Murr et al., Sports Medicine — Open, 2018, on video feedback and motor skill acquisition.