I’m pretty sure this is covered by most ‘fair use’ clauses (do check your own laws: IANAL) but is intended for people with a DVD and a DVD-ROM drive who want the soundtrack to the film but don’t feel the need to pay twice for the same material on different media…

Pretty much all you need to know can be found at Shepmaster’s site, but there are only two pages that matter: how to turn the DVD into AAC files and then how to turn AAC files into stereo audio files.

Do Google for the most current sites, but at the time of writing you can find the 0SEx program here, and the mAC3dec project here. Download and expand both those binary files, shove in a DVD (in my case Koyaanisqatsi), quit any auto-launched DVD player app and start up 0SEx.

The only tricky part is figuring out which Title has the film – each Title can contain many Chapters, so choose the Title that has the same number of Chapter entries as the film inlay says it has scenes. Titles are used to contain menu items as well as the main feature, but in my case the film has 16 Chapters as so is easy to spot. Click on Ti and choose the correct title. If you don’t want all of the film chapters, click on Ch and choose the ones you want. Next, turn off the video decode (click on the Vid button, and click to turn off the tick mark), and then turn off the subtitle extraction (click on the Sub button, and click on each tick). There are menu items under Control that do this for you, if you are feeling more adventurous.

Change the format of the extracted files by clicking on Fmt and choosing Elementary Streams so that the audio comes out in it’s own file (and not in a VOB with no image data), and then click on Seg and choose Chapter, so that each scene is split into a separate file. Then click on BEGIN and choose a destination directory.

Wait a while and you should have a collection of .ac3 files in their own directory – the most useful thing to do is to convert them to .wav or .aiff files whilst downmixing from 5.1 to 2.0 and applying a global volume normalisation. Eh ? Ok: the AC3 files can have a much greater dynamic range than ‘normal’ 16-bit 44.1kHz WAV files, so the Normalising process means that the maximum and minimum volume of each track is noted and used to scale the final WAV/AIFF files so that the audio for the entire album fits comfortably into the range available. Still sounds odd ? Then trust me: without Normalising you will most likely find that the quiet bits are too quiet, and the loud bits too loud for comfortable music listening.

Start up mAC3dec. I’m aiming to playback the final result via iTunes, so choose AIFF from the Format menu, then 44.1kHz from the Sample rate options, tick Normalize and tick Globally, and check that Split Channels is left unticked. Now go to File->Add AC3 and select all of the files that make up your DVD audio. Once they’re loaded, click Start and wait: if you like to see graphical progress bars then make sure you’ve visited the mAC3dec->Preferences menu and unticked the Disable Progress Bar option.

The program will scan through all of the files once to record the volume highs and lows for each track, and then setabout converting them to plain 2.0 (stereo) AIFF files. Once this is complete, do with them what you will ! I opened up iTunes, added the AIFF files to the Library and then selected all of them and used Advanced->Convert Selection to MP3. After all had been converted I deleted the AIFF originals from the Library and added ID3 tags to taste.

Yes, you can skip a step and get mAC3dec to convert from AC3 directly to MP3, but I haven’t had chance to mess with the MP3 encoder in mAC3dec so I can’t vouch for what differences (if any) there are from the iTunes encoder. I quite liked the idea of having the AIFF files around for a while in case I wanted to burn a pure Audio CD from them, but so far haven’t taken that step.