Some DVD-Audio discs extract to very small result files that contain only about 1 second of noise. What could be wrong?

If you are running AnyDVD (or other similar software) that runs at background and tries to decrypt the disc silently, you'll need to turn it off before extracting from DVD-Audio discs.

This is because AnyDVD can't handle DVD-Audio discs and will give wrong output to up-layer software like ours.