If the Redmi Pad SE screen automatically turns off while playing videos, please refer to the following to troubleshoot:
1. Check the screen timeout settings. Go to [Settings] >> [Lock screen] >> [Sleep] >> select [10 minutes] to extend the screen on time;
2. Make sure Battery saver is turned off, especially while watching videos. Go to [Settings] >> [Battery] >> turn off [Battery saver];
3. Open a video in an APP like YouTube, on the video playback interface, select [Settings] >> [Sleep timer] >> select [Off];
4. Update the system and video APPs to the latest versions to fix potential bugs;
5. Play a video in Safe mode. If the issue doesn't happen, an APP you installed could be causing it;
6. If the issue persists after all steps, consider a factory reset (after backing up your data).