DVD Audio Extraction with Ac3Dec

Ac3Dec is an excellent program for extracting AC3 audio and converting it to PCM Audio. It can handle almost any Vob or AC3 file with ease. The quality is not quite as good as GraphEdit, but perhaps that will be fixed in future updates. As always the DVD Vob files need to be decrypted to your hard disk or Ac3Dec will not be able to read them.

Put the Ac3Dec.exe file in a folder on your main hard drive (usually C:) and start up Danni's GUI. Click on the AC3DEC button at the top (encircled in red) to bring up the Ac3Dec page we see below us. There are lot of little useful options in Ac3Dec but these are not necessary to explain here. I will just concentrate on the important task of getting the audio =).

Press the (A) button and select the location of the Ac3Dec.exe file.

Then tell it where the first Vob of your movie is by pressing (B) and selecting it.

You can choose either a Vob or an AC3 file if you wish.

And then tell it where you want to save your final Wave by selecting (C)

DECODING SETTINGS

I always set the Global Output Gain (D) to 500 to help boost volume. You can also turn up the 'inverse-squared gain' if it is still a bit low. If you turn too many channels up you will generally get distorted audio, so be careful. But play about with these settings until you are happy with the output. To test the volume etc., press the 'Play Source' button (G).

If you have more than one Vob file (as is almost always the case), make sure the 'Span Over Multiple VOBS Automatically' (E) is checked. It is important that your Vob files are numbered in order for this to work. So you should have something like:

This way, when it comes to the end of the first Vob, it will look for the next one in the list.

One last buy very important option is (F). Since a DVD can have many language tracks we have to select the correct one. Usually the default '1st stream' option is English. But test it by hitting the 'Play Source' button again (G). Listen to see what language is played, if it is the wrong one, select the next one above it. If that is wrong try the next one above that and the next and so on, until you find the correct audio track you want.

When everything is done press the large 'Create my Wav' button.

Up will pop a selection box asking for what audio format you want the DVD AC3 converted into. Choose PCM 48,000Hz 16 Bit, Stereo. You could also choose MP3 if you wanted, but for best results you will need to use PCM. This way you can multiplex it to the video file and compress it using VirtualDub.

Thats it! A window like the one below will appear telling you the progress of your conversion. Ac3Dec converts to PCM audio in real time, so it will take as long as watching the movie to convert it into a Wave file.