Video Conferencing - Flickering Videos (MacOS)

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Troubleshooting Guide: Flickering Videos in a Video Conference

Symptom

You are in a lesson in the Slingui virtual classroom and other participants’ videos keep flickering—turning on and off by themselves. Audio, however, generally remains stable.

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🔍 Why Does This Happen? Understanding the Problem

This behavior is rarely caused by a fault in other participants’ cameras. It is actually the video conferencing platform’s intelligent self-protection system acting on your computer.

Here is how it works:

1. Audio Takes Priority: The platform’s number one priority is keeping the conversation flowing. Audio must not fail.
2. Overload Detection: The system constantly monitors two things on your computer: internet stability (download) and processor (CPU) usage.
3. Automatic Corrective Action: If your internet fluctuates or your computer struggles to process multiple videos at once, the system takes action to prevent worse outcomes (such as a dropped call or interrupted audio): it temporarily turns off other participants’ videos, which are less essential than audio.
4. The Flickering Effect: When the system turns off the videos, resource consumption on your computer decreases. With this extra capacity, the system tries to turn the videos back on. If the overload persists, it turns them off again. This cycle creates the flickering you see on screen.

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🛠️ How to Resolve It: Steps to Stabilize Your Connection

Follow these recommended actions to stabilize incoming video, especially on MacOS with Google Chrome.

1. Check Your Network Connection

• If you are using Wi-Fi: Move closer to the router. If your network offers options, connect to the 5GHz network, which is faster and experiences less interference than the 2.4GHz network.
• Check other devices: Make sure other people or devices in your home are not using all your bandwidth (e.g., streaming in 4K, downloading large files, or gaming online).

2. Enable Hardware Acceleration in Chrome (Critical Step)

Processing multiple videos simultaneously places high demands on your computer. This setting transfers the heavy work to your graphics card.

• Action: In Google Chrome, go to Configurações (Settings; you can use ⌘ + , on Mac).
• In the side menu, click Sistema (System).
• Enable “Usar aceleração de hardware quando disponível” (Use hardware acceleration when available).
• Restart the browser for the change to take effect.

3. Adjust Your Mac’s Power Mode

MacBooks may limit processor performance to save battery power, directly affecting their ability to process video in real time.

• Action: Click the battery icon in your Mac’s top menu bar.
• If “Modo Pouca Energia” (Low Power Mode) is enabled, disable it.
• If possible, keep your MacBook connected to its charger during the lesson.

4. Manage Background Tabs and Applications

Chrome uses many resources for each open tab, and other applications may be using your processor without you realizing it.

• Action:
  1. Close all other browser tabs that are not essential for the lesson.
  2. Close other applications running in the background (Spotify, Discord, Steam, etc.).
  3. For a more advanced analysis, press Shift + Esc in Chrome to open the browser’s Task Manager and check whether an extension is using a lot of CPU.

5. Test with Extensions Disabled

VPN extensions and ad blockers can sometimes interfere with the platform’s video protocol, causing instability.

• Action: Try accessing the lesson in a Google Chrome Janela Anônima (Incognito Window; shortcut: ⌘ + Shift + N).
• Diagnosis: If the problem disappears in the incognito window, one of your extensions is the likely cause. Disable them one by one in your regular window to identify the conflict.

6. Check Screen Recording Permissions (A Hidden MacOS Issue)

Newer versions of MacOS (Sonoma, Sequoia) have stricter privacy rules that can indirectly affect video performance in Chrome.

• Action:
  1. Go to Ajustes do Sistema > Privacidade e Segurança (System Settings > Privacy & Security).
  2. Look for Gravação de Tela (Screen Recording).
  3. Check that Google Chrome has permission to record the screen (its toggle should be on).
• Why does this matter? Even when you are not recording, Chrome uses this same system API to manage and render video windows efficiently. Missing permission can cause unexpected behavior.