Show HN: In response to the new EU copyright laws, an API to filter user uploads
filteruploads.com
filteruploads.com
I'm not even sure if there exists a corpus of copyrighted content anywhere to compare against. You're probably going to have to build it yourself. And keep it up to date with not just newly generated content, but also content whose copyrights expired.
Frankly, even for companies of the FAANG scale, this is a tough challenge, and I don't think a startup is going to be able to handle this.
You are correct that its a big task, but if one would take it step by step and start with pictures only I am pretty sure you could come up with a decent success rate.