What Is Loop Recording? How Dash Cams Save and Overwrite Video
Loop recording is the way a dash cam records nonstop without running out of space. The camera saves video in short clips, often one to three minutes long, and when the memory card is full it automatically deletes the oldest unlocked clip to make room for the newest one. Clips that the camera has locked, because it detected a crash or you pressed the save button, are protected from being overwritten.
That’s why you never have to clear a dash cam’s card manually, and also why everyday footage only lasts until the card fills up again.
Table of Contents
How Loop Recording Works, Step by Step
- You start driving. The dash cam powers on and starts recording.
- Video is split into short clips. Each clip is saved as a separate file on the microSD card.
- The card fills up. When there’s no space left, the camera finds the oldest unlocked clip.
- The oldest clip is overwritten. The new clip takes its place, and recording continues without interruption.
- Locked clips are skipped. Clips saved after an impact or a manual save stay on the card until you delete them.
California’s vehicle code describes the same idea in its definition of a video event recorder: a device that “continuously records in a digital loop” and saves video when triggered by unusual motion or a crash (California Vehicle Code section 26708).
Locked Clips: How Important Footage Is Protected
Dash cams protect clips in two main ways:
- Automatic (G-sensor): the built-in motion sensor detects a sudden jolt, such as a collision or hard braking, and locks the clip from that moment.
- Manual: you press an emergency or save button, or use a voice command on some models.
Locked clips usually go into a separate folder. If that folder fills up, some cameras stop locking new clips or start overwriting the oldest locked ones, so check your camera’s behavior and clear old locked files periodically.
How Long Does Footage Last Before It’s Overwritten?
There’s no single answer. It depends on:
| Factor | Effect on how much footage you keep |
|---|---|
| Memory card size | Larger cards hold more before looping |
| Resolution | 4K files are much larger than 1080p |
| Number of cameras | Front, rear, and cabin cameras all share the card |
| Bitrate and compression | Higher bitrate means bigger files; H.265 saves space |
| Parking mode | Parking recordings also use card space |
Your camera’s manual or app often estimates how many hours fit on a given card size.
Choosing a Clip Length
Most dash cams let you choose clip lengths of 1, 2, or 3 minutes.
- Shorter clips are smaller and quicker to download over Wi-Fi, and only a small amount of video is locked after an incident.
- Longer clips mean fewer files to sort through but bigger downloads.
One to three minutes is a common, sensible range.
Loop Recording Tips
- Use a high-endurance microSD card. Loop recording writes to the card constantly, which wears out standard cards faster.
- Format the card periodically if your camera’s manufacturer recommends it, using the camera’s own format function.
- Adjust G-sensor sensitivity. If it’s too sensitive, bumps and potholes will fill the locked folder.
- Save important clips right away. After an incident, download the footage to your phone or computer before it’s overwritten.
- Check the card occasionally. A failing card can stop recording without you noticing. Some cameras warn you.
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A front-and-rear camera with Wi-Fi makes it easy to save locked clips to your phone.
- 【Dual STARVIS 2 Sensors】The A229 Plus is the first Front and Rear dashcam to feature two Sony STARVIS 2 IMX675 image sensors. This advanced technology offers 2.5 times dynamic range and 2.5 times light sensitivity compared to STARVIS, resulting in reduced noise and motion blur during night recording. The A229 Plus provides the ultimate solution for capturing clear and detailed footage, making it a revolutionary addition to any driver's safety toolkit.
- 【HDR Front & Rear Recording】The A229 Plus dash camera is a game-changer in the industry, setting the standard for dashcams with its advanced Dual-Channel HDR technology. This reveals accurate 2K details even in fast-moving scenarios, and its exceptional ability to capture car license details makes it stand out from the competition. (Note: The front cam 1440P 60fps is not available while HDR is enabled. )
- 【2-channel 1440P recording】The A229 Plus dashcam offers upgraded 2K + 2K front and rear recording capabilities with 1440P resolution for high-definition recording effects. This innovative dash camera provides exceptional clarity and color saturation, enabling true 1440P detail reproduction and enhanced color accuracy. The front camera has a high frame rate of up to 60fps, ensuring crystal-clear images, accurate color representation, and perfectly balanced exposure levels.
- 【Hands-free Voice Control & Notification】Go hands-free with the A229 Plus dashcam's 12 voice commands, including take photo, lock the video, turn on WiFi, and show front/rear camera and so on. A229 Plus Dual channel dashcam also provides clear notifications for settings changes or memory card errors, keeping you focused on the road and enabling you to control your dashcam easily and safely.
- 【Ultra-Precise GPS】The A229 Plus is equipped with a state-of-the-art Quad-Mode GPS module that supports 4 satellite positioning systems: GPS, BEIDOU, GALILEO, and GLONASS. This advanced feature significantly enhances the accuracy and stability of the positioning. lt provides detailedlocation, speed, and time data of the vehicle when playing back the video on VIOFO App or computer.
For more, see how do dash cams work and our guide on how to install a dash cam.
Can You Turn Off Loop Recording?
Some cameras let you disable it, but then the camera stops recording when the card is full. For most drivers, leaving loop recording on is the safer choice, because it means the camera is always recording.
Frequently Asked Questions
Does loop recording delete my crash footage?
Not if the clip was locked. Locked clips are protected from loop recording. Download important footage soon after an incident anyway.
What size memory card is best for loop recording?
Use the largest size your camera supports if you want to keep more footage, especially with multiple cameras or 4K. Check the manual for compatibility.
Why is my dash cam full of locked files?
The G-sensor may be too sensitive. Lower the sensitivity and delete old locked files you don’t need.
Is loop recording only for dash cams?
No. Security cameras and other continuous recorders often use the same method.
The Takeaway
Loop recording keeps your dash cam recording nonstop by overwriting the oldest footage. Locked clips protect what matters, so set the G-sensor sensibly, use a high-endurance card, and save important videos promptly.
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