The software on the website - audiostrip.co.uk - was free to use for this case. They offer some paid options for speed, etc. There are other sites out there doing this both online and through mobile or desktop software. It all is done in the cloud as the computing power to pull this off is still rather large (or at least specific). There is a standalone application called Izotope that does similar things (that is cloud free) - but the results weren't nearly as dramatic or good.