OnlineVideoConverter is not safe. When opening the site, I receive the warning: Your connection is not private. Attackers might be trying to steal your information from www.onlinevideoconverter.com.
Use a desktop video converter such as WinX Video Converter and Handbrake. You can download from their official websites.
https://www.winxdvd.com/video-converter/.
https://handbrake.fr/.