Video Conferencing - Flickering Videos (Windows)

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Troubleshooting Guide: Flickering Videos in a Video Conference

Symptom

You are attending a lesson in the Slingui virtual classroom and other participants’ videos keep “flickering”—turning on and off by themselves intermittently, while audio generally remains stable.

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🔍 Why Does This Happen? Understanding the Problem

This behavior is not a fault in the other students’ or teacher’s cameras. It is an automatic protective response from the video conferencing platform, designed to handle limitations in your computer or internet connection.

The system works as follows:

1. Audio Takes Priority: Keeping the conversation uninterrupted is the platform’s top priority. Audio must not fail.
2. Constant Monitoring: The system continuously checks two factors on your computer: internet stability (for receiving data) and processor (CPU) usage.
3. Corrective Action: If your internet fluctuates or your processor becomes overloaded while decoding several videos at once (CPU usage above 80%, for example), the system takes action to prevent the call from dropping or audio from freezing: it temporarily turns off incoming videos.
4. The Flickering Effect: When the system turns off videos, resource consumption on your computer decreases. With this extra capacity, it tries to restore the videos. If the overload returns, 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 Call (Windows + Chrome)

Follow these recommended actions to reduce the load on your system and stabilize incoming video.

1. Adjust the Windows Power Plan (Crucial Step)

Windows often limits computer performance to save power, directly affecting its ability to process video in real time.

• Action (Laptop): Click the battery icon in the taskbar and move the slider to “Melhor Desempenho” (Best Performance).
• Action (Desktop): Go to Painel de Controle > Hardware e Sons > Opções de Energia (Control Panel > Hardware and Sound > Power Options) and select “Alto Desempenho” (High Performance).
• Recommendation: Always keep your laptop plugged in during lessons.

2. Enable Hardware Acceleration in Chrome

This setting makes Chrome use your graphics card (GPU) to process images, freeing up the main processor.

• Action:
  1. In Chrome, go to Configurações > Sistema (Settings > System).
  2. Make sure “Usar aceleração de hardware quando disponível” (Use hardware acceleration when available) is ON.
  3. If it is already on, try turning it off, restarting the browser, and turning it back on. This can help “reset” communication with the graphics driver.

3. Prioritize Your Network Connection

Flickering is a classic symptom of Wi-Fi instability.

• Action (Wi-Fi): If your router has two networks, connect to the 5GHz network (usually with “5G” or “5GHz” in its name), as it is more stable and experiences less interference.
• Action (Ideal): If possible, connect a network cable directly from your router to your computer. A wired connection is always more stable than Wi-Fi.
• Tip: Make sure other people or devices in your home are not performing bandwidth-intensive activities (4K streaming, large downloads) 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. Update Graphics Drivers

Outdated drivers (Intel, NVIDIA, or AMD) are a common cause of video processing failures in Chrome.

• Action:
  1. Check for pending updates in Windows Update. Go to Configurações > Atualização e Segurança > Windows Update (Settings > Update & Security > Windows Update) and click “Verificar se há atualizações” (Check for updates).
  2. Remember to look under “Opções avançadas” (Advanced options) or “Atualizações opcionais” (Optional updates), as graphics drivers often appear there.