Youtube Video Copyright Checker Online
The Copyright Match Tool helps you locate re-uploads of your original videos on other YouTube channels. If a match is found, you can review it in YouTube Studio and decide how you want to proceed.
https://support.google.com/youtube/answer/7648743?hl=en
The Copyright Match Tool helps identify videos on YouTube that are identical or very similar to your own video. When you upload your original video to YouTube, the tool will start searching for videos that were uploaded after yours to see if they are a match.
https://creatoracademy.youtube.com/page/lesson/protect-your-copyrighted-content-on-YouTube_copyright-match-tool_video
How do I check for copyright infringement on a video before uploading it to YouTube?
https://www.quora.com/How-do-I-check-for-copyright-infringement-on-a-video-before-uploading-it-to-YouTube