Video/Cassette Recorder Data Help?

My dad has a Video Cassette Recorder/Dvd Recorder RDR-VX535, and one day he found a disk that the computer said was an empty disc but when he put the "empty" disk into the recorder, the recorder was able to play it, so he probably assumed that the computer cannot read the data code in the disk since it was copied from one of those old-fashioned large black tape thingies that takes a long time to rewind or fast-forward. My dad tried to save it into the computer so he can edit it with Videostudio, but his HDMI thing did not work as the jacks are only outports, so the DVD recorder cannot connect with the computer, only the monitor. Is there a way to transport the data from the so-called "Empty" disk into readable data that can be saved into the computer?