Devices & troubleshooting FAQ

On a phone you can upload a clip from your camera roll, or record with RecordAssist, the guided recorder. Neither needs an account. Because the analysis happens on your device, an older phone takes longer than a new one.

If analysis is slow or stalls, open Advanced capture settings in Motion Lab and set Tracking accuracy to Fast, which is meant for older phones.

For what your browser needs, see which browsers work.

• Analyzing an uploaded clip: the browser has to decode the video and download and run the body-tracking model. It uses the graphics chip where it can and a slower fallback where it cannot.
• Recording with RecordAssist: camera access over a secure (https) connection, plus in-browser recording. Without recording support you can still upload a clip.
• Live body tracking while you record: WebGL graphics support. Without it, RecordAssist falls back to manual framing guides.
• Spoken guidance: speech support in the browser. Without it, on-screen captions still guide you.

Private or incognito windows can block storage on the device, so analyses and kept clips may not survive closing the window.

If one browser keeps failing on the same clip, try another browser before re-filming anything — the problem may be the browser, not the video.

What probably happened: an earlier prompt was answered with Block, so the browser now refuses without asking. If the browser never asks at all, check that the browser app itself is allowed to use the camera in your device settings.

• "Camera access was blocked" — allow it in site settings, then try again.
• "Camera is in use" — another app or tab has the camera; close it.
• "No camera found" — this device has no camera the browser can use; switch to a phone.
• "Guided recording isn't available here" — camera access needs a secure (https) connection and a browser that exposes the camera.

You never need the in-app camera to get an analysis: film with your phone's normal camera app and upload the clip to Motion Lab. RecordAssist only uses the camera while its screen is open, and the live preview is never uploaded or saved.

What probably happened: Motion Lab looks for a person in the frames it samples. If it finds you in fewer than about half of them, the reads are partial and lower-confidence. If it finds you in almost none, the capture is graded not defensible and anything it keeps is heavily capped. If it finds you in none at all, there is no athlete in the evidence, so it withholds the results instead of guessing.

What to try with the same clip: trim it to the rep so the samples land on you rather than on an empty court or bay, and run it again. Running it again is also the first step for the engine and frame-reading failures described above; if frames fail twice, try another browser on the same clip. Re-record when the results say your body could not be reliably found, and next time:

• fill about half the frame height, head to feet, with a little room above and below;
• film in even light that faces you, not from behind you;
• keep only yourself in the shot, with the phone propped steady.

Results that instead say no swing was found, the clip stops before the swing finishes, or the video looks sideways mean Motion Lab did find you — see when the One Fix is missing.

Read next: getting your whole body in frame and the best lighting and background.

Golf: automatic clubhead tracking is not reliable enough yet to draw the club's path by itself, so Motion Lab traces your hands. To trace the clubhead, open the video in your results, choose Mark clubhead and tap the head on a few clear frames through the swing — your marks become the trace. See club path versus the clubhead trace.

Other sports: where the bat, racquet or paddle head was picked out in the frames, the trace follows it and says in how many analyzed frames it was seen. Where it never was, the trace follows your hands, or is labeled as projected out along your forearm. Either way, treat its shape as directional.

What helps: keep the whole implement in frame through the finish, film at 60 fps so it does not blur through contact, and pick a background it stands out against. Your body-position reads come from the tracked joints, so they still stand when no path is drawn.

Capture quality sets a ceiling: a Usable clip stops short of a Good one, and a Limited or Difficult capture is held at low confidence. No amount of analysis lifts a read above what its footage supports.

The sport sets a ceiling too. Golf has the deepest analysis; the other sports get directional reads with a lower maximum, so a perfect clip in those sports still stops below what a golf clip can reach. See why confidence is capped by sport.

1. Read the limiter named with your result.
2. Apply the fix it lists — the capture changes are specific to that clip.
3. Re-film from the same spot, so the new clip can be compared with the old one.

Low confidence does not mean the finding is wrong. It means treat it as a lead to check rather than a conclusion — see what confidence means.

• Fast motion — between analyzed frames the overlay is filled in from the nearest ones, so it can lag a quick arm, club or racquet.
• Hidden joints — an arm behind your body or a foot out of shot is placed with less certainty.
• Blur and low light — soft frames make joints jitter.
• Someone else in frame — the tracking can jump to the other person.

What helps: a steady camera, 60 fps, even light and only you in frame all tighten it. Small offsets are normal for positions read from one camera; large, consistent ones are worth a re-film.

If the overlay is badly off all the way through a clean, well-lit clip, tell us the sport, motion and device you used.

• The engine couldn't start — a one-time download it needs did not complete. Check your connection and run the analysis again; your video is still not uploaded for analysis.
• The device couldn't read any frames — run it again, and if it fails twice, try another browser on the same clip before re-filming.
• A step took too long — try a shorter clip, or set Tracking accuracy to Fast under Advanced capture settings.
• The page was closed or reloaded — open Motion Lab again and choose "Continue with this clip" under "We kept your last clip".

Re-record when the failure is about the footage: no athlete could be found, no swing was found, the clip stops before the swing finishes, or the message names darkness, cropping or no clear motion. If it says the video looks sideways, rotate it upright and upload that copy instead — the footage itself may be fine. The highlighted box on the error screen says whose side the problem is on and gives the specific fix.

No usable clip right now? The error screen also offers a starter plan from three quick questions, labeled as self-reported rather than measured from video. If it keeps failing, contact us.

• The 20-second limit — a cap, not a fault. Tap Record when you are nearly set and let the countdown take you into the rep.
• "Recording stopped unexpectedly" — the recorder failed. Try again; if it keeps happening, use your camera app and upload the clip instead.
• "This browser can't record video" — in-browser recording is not supported here. Filming with the camera app and uploading works just as well for analysis.

Finished takes are saved on your device before analysis, so a reload does not lose them — Motion Lab offers the take back as your last clip.

Want more of your practice on camera? Record separate takes of the reps you care about; see how long a clip should be.

• Not signed in — without an account, results run from the summary to the main issue. Creating a free account or signing in brings you back to the same place.
• No read at all — the results stop at the summary when no person could be tracked anywhere in the clip, no swing was found, the clip stops before the swing finishes, the video looks sideways, or the analysis engine never started or could not read any frames. Run it again if the engine failed, and rotate the video upright if it looks sideways. Otherwise check it is the right clip and was not trimmed short, then re-film if needed — whole body in frame, from just before the swing until after the finish.
• No clear priority — the One Fix step only fills in when the analysis found a fix to recommend.

What to try: sign in and reopen the analysis. If it was withheld because of the clip, follow the fix the result gives — usually a re-film; see why re-filming can come first.

• Different camera angle — rotation and path reads are not directly comparable.
• Different distance or height — you fill the frame differently, or the camera sat higher or lower, so posture and turn changes partly reflect the camera.
• Different frame rate — speed and timing changes are not directly comparable.
• One clip cropped your lower body, missed contact, or was not reliably analyzable.
• Different handedness — the clips are set to different hands, or one clearly moves like the other hand, which usually means a front camera that mirrors the video. Lead-side reads flip.
• A different motion, shot or club — a chip against a full swing, for example — or another athlete's clip.
• An analysis update between the two clips — they were read by different versions of the analysis, so their numbers are not defined the same way.

After an analysis update, re-filming the same way will not change the answer: compare against a clip filmed since the update instead.

For everything else, re-film the retest to match the original — same angle, same distance and same equipment — from the same prop and spot, with the same handedness set and a camera that does not mirror. In RecordAssist, "Record the same angle again" reopens a setup you saved.

Even a clean comparison of two videos is a directional read, not a measured result. See retesting under the same conditions.

• The motion does not match the clip — each motion has its own phases and reads, so a chip analyzed as a full swing, or a volley as a forehand, reads oddly.
• Handedness was wrong, or left on "Not sure". If the results ask whether your clip is mirrored, it moves like the other hand — usually a front camera that mirrors the video.
• A slow-motion clip left at Normal speed — timing and speed reads come out off by the slow-motion factor, or are withheld when a golf swing looks slowed down. Set the slow-motion speed you filmed at; angles and positions are unaffected.
• The camera angle chosen under Advanced capture settings does not match how the clip was filmed.
• The capture was graded Limited or Difficult, so the read is provisional.

What to try: choose the clip again with the corrected settings and re-run it. If everything was right, film another rep from the same spot — a finding that shows up again is more trustworthy than one that appears once.

Still think it is wrong? Disagreeing with your One Fix explains your options, and you can report a result that looks broken through the contact page.

To help us fix a problem quickly, include:

• the device and browser you used;
• the sport and motion;
• the exact message you saw, or the step where it stopped;
• whether it happens with more than one clip.

The form takes text only, and there is no need to send your video.

For privacy or deletion questions, the privacy policy explains what you can do yourself from Settings. Security issues go through the vulnerability disclosure policy.