The purpose of this application/add-on is not to record YouTube playback, but to enable playback of XESC files on machines that do not have Expression Encoder installed.
If you want to record YouTube playback, simply use a desktop recorder application like Bandicam or Camtasia. They are not free, but you can successfully test the features in the trial versions without any limits, then decide to buy or now.
Alternatively you can use YouTube downloaders to save the entire video file directory to your PC.