Question
I want to start an aio website like it consist of mp3, music videos and 18+ videos which will be easy one click download, do we want to get licence or is it enough if we mention thanks.
Answer
If you don't have a license, you can't legally offer the file to download, unless it is shared with one of a select number of free licenses that don't require attribution. A "thanks" is no legal protection against DCMA takedown notices and RIAA or MPAA lawsuits.
So in short: you need licenses.