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What are video motion detection windows and how do I set them up?

Video motion detection (VMD) can identify motion without using a motion detector. It uses software to identify motion in the images based on changes in brightness and colour. VMD cameras must be set up correctly to avoid false alarms.

How does video motion detection work?

With Bell Smart Home video services, you can adjust the sensitivity to motion and the size of the targets captured by your cameras. The camera can have three VMD windows. When it detects motion within these windows, it starts recording.


  • A Bell Smart Home video services subscription
  • A computer with the latest version of Adobe Flash

To adjust motion detection settings (from a computer only):

  1. Log in to your service with a browser.
  2. On the left menu, click Video.
  3. At the top of the video page, click Settings.
  4. Select a camera from the Video device dropdown menu.
  5. Scroll down and click on Video motion detection (VMD).
  6. Click 1, 2 or 3 to select the corresponding VMD window. Use the mouse cursor to draw the VMD window in the areas where you’re looking to capture motion.


  7. Adjust the sensitivity of the VMD by selecting from a range of 1 to 10 (10 being the most sensitive). VMD2_EN
  8. Adjust the target size of the VMD by selecting from a range of 3% to 30%.
  9. IMPORTANT: Click Save to save the setting of the current VMD window before adjusting a different window.

**VMD options do not apply for doorbell cameras.

Best practices

While there is no one perfect setting, as each customer’s scenario is unique, there are some best practices to follow to ensure the best performance.


The above image is an example of using VMD best practices.

  • Use all three windows and keep them as small as possible.
  • VMD windows work best when drawn like trip wires. Use long narrow boxes to create a “trap zone” where someone is likely to pass by.
  • Avoid creating boxes that cover the whole screen.
  • Avoid overlapping VMD windows, which can lead to false triggers and unwanted recordings


  • Avoid placing VMD windows in highly dynamic areas. Consider how the lighting may change throughout the day. An area that was not shaded may become shaded later in the day.
    • Trees and bushes (which can move due to wind).
    • Streets and sidewalks.
    • Large reflective surfaces.
    • Areas where shadows are likely to move.

Target size

Target size is the percentage of the window that includes movement to trigger a recording.

  • If the target size is too large, it could only trigger recordings for very large objects such as a car.
  • If the target size is too small, leaves blowing in the wind may trigger recordings.

To determine which target size to use, try to estimate what percentage of the window the target (person, car, animal, etc.) would fill and select one size larger.


Example: If a person takes up 15% of the VMD window, set the target size to 20%. That percentage would pick up a person, but is less likely to pick up something smaller (i.e., a stray shadow).


Sensitivity determines how drastic a change in the view of the camera must be to trigger a clip. For example, a cloud moving slowly across the screen may trigger a video clip if the sensitivity is set high enough, whereas a lower sensitivity may not trigger a recording for the same amount of motion.

Start at a sensitivity of 7 and adjust up/down based on your needs and on what the camera is capturing.

  • Higher sensitivity means a smaller shift is needed to trigger a clip.
  • If the sensitivity is too high, the camera might be triggered constantly.