If the video keeps flickering, please follow the below methods to do the troubleshooting:
1. Make sure the TV has one video source. For example, if you use the HDMI and the USB media together, please remove one of the video sources.
2. Plug the TV into the socket only, and unplug other electric appliances from the socket.
3. Try to power cycle the TV. You could unplug the power cord from the socket and plug it back in.
4. Try to restore the TV back to the factory settings: press the Home button and select Settings Device Preferences Factory Reset.
5. If the TV has internet access, please check if there is a new version of software updated online or not.
Press the Home button on the TV remote, and select Settings Device Preferences About System update Network Update:
If the issue cannot be resolved, please feel free to call the TCL hotline for further help.