drngr said:

If only an HDTV can decode them, they're digital ClearQAM. A simple USB stick like this should allow you to record the original transport stream data. I'm not sure what a good one is, since most reviewers use these for over-the-air.

Better yet, get a USB stick that can also snag the analog stereo signal (RCA connectors) right from your TV's audio in/out (may require a Y-cable for easier access):

Newegg: KWorld Hybrid TV Stick UB445-U2 USB 2.0 Interface

Note the "multi-cable" adapter for composite, S-video, & L/R audio.

Normally I'd suggest using your DVD recorder as the capture device, but this USB stick puts the signal directly into your computer, where you can make up a proper MP3 with tag info, album cover picture, and such, at minimum fuss. ;)