Even if they didn't edit it themselves, it's still a very niche thing, I just went to Youku and found the video in question, however it wasn't recognized by any of the various song recognition software.
So you'll just have to convert this video to MP3 format.
You can get a Format Factory, which is very easy to use, and you can do it according to the following method on Baidu Experience.
/article/86112f135c3e4c27379787b1.html
Wish you success.