I am amazed and appalled that none of the answers I got from Google on this worked with the DVD I had. Codecs and formats are still beyond standardization, I guess. Fortunately, Doom9 came to the rescue. The short answer is to rip the raw sound from the DVD as a WAV file, edit it, and save it as an MP3. It takes two freeware programs.
- Get eac3to, a command-line Windows tool.
- Find the VOB file on the DVD that has the sound you want, and copy it to your hard drive.
- Open a command window in Windows, and give the command
eac3to.exe source-from-dvd.vob dest-temp.wav
- Get Audacity, a wonderful freeware sound editor.
- Edit the dest-temp.wav file, selecting just the bit you want. Export that bit as a new MP3 file. Audacity has a zillion other tools you can work with to clean up the sound.
(Edited the original article to remove the need for VLC, which makes the process much faster.)