The older post on this topic mentioned DVD Decrypter and others. This time, for some reason, that method did not work. Perhaps because of some mistake in the sequence of steps, I suppose, the resulting file was a VOB file and not an mp2 file. Anyway, the file was not being opened by any of the AC3 decoding methods like WinAmp plugin etc.
So, this time, I tried just copied the VOB files to the hard disk and opening them with VirtualDubMod, extracting the audio stream using Streams -> Stream List -> Save wav. That wav was opened using Soundforge, using AC3 codec. Slightly buggy, since each VOB file's wav data had the duration info of the entire program chain, and so had some sort of repeating audio after the first 25 minutes or so which had to be cut out. But otherwise OK.
So, this time, I tried just copied the VOB files to the hard disk and opening them with VirtualDubMod, extracting the audio stream using Streams -> Stream List -> Save wav. That wav was opened using Soundforge, using AC3 codec. Slightly buggy, since each VOB file's wav data had the duration info of the entire program chain, and so had some sort of repeating audio after the first 25 minutes or so which had to be cut out. But otherwise OK.