You might see your Time Stamp setting when uploading your video is automatically checked by default. Please see the below steps on how to change this default setting. 

1. Check the Case Type of the case you are uploading the video into.  It's located on the Case Details page of the file you're working in. 

2. Go to Settings

3. Click on Case Type under Case Customization

4. Click the Edit icon next to the Case Type you need to make changes in. 

5. Near the bottom there is a setting named "Add Timestamp to Video". Change that to "Default Unchecked" and then click Submit.