While DVD recording is currently a contentious issue, there is more and more demand for DVD backup software. As DVDs are vulnerable to scratches and general deterioration, sensible people are looking to create copies. We'll try here to explain some of the problems you may have experienced while copying a DVD and offer you a simple solution. In short, the copied disc will have the benefit of being region free, allowing you to play it on 'any' DVD player.

What’s on a DVD?

Once you have purchased a DVD you want to copy, place it in your DVD-ROM drive and check out its contents. Within the disc you will find several folders. Normally you should see a VIDEO_TS and AUDIO_TS folder. The AUDIO_TS folder is used to store DVD Audio, the VIDEO_TS to store DVD Movies.

We're focusing on a movie DVD, so we’ll enter the VIDEO_TS folder. In this folder you will find .VOB .BUP and .IFO files. The VOB file contains the actual movie files - MPEG-2 encoded. MPEG-2 is a method of movie compression, just as MP3 files compress audio. The file will also contain audio, normally found in a compressed format. This is an improved form of MP3, named AC-3. The .VOB files will also contain subtitles and multiple camera angles.

The .IFO files are the information files, used by your DVD playing device. It gives the DVD player information on what .VOB files to load and when - e.g. when to start a new chapter. The .BUP files are simply a backup of the IFO files and generally have no use, they will only be used if an .IFO files becomes corrupt.

Let’s copy those files!

You would think it would be as easy as copying files to a folder on your hard disk and then burning the lot to a recordable DVD, but unfortunately DVD producers don't make it that easy. The files copied will contain useless data and your copy will not work.

DVD movies are protected by a Content Scrambling System (CSS), a protection developed and adopted by Hollywood Studios. It simply protects them from pirates who want to make copies to sell in bulk. The protection encrypts the data on a DVD and requires a special key to decrypt it. Some DVD playing software developers have received a key from the studios allowing their software to read the information, but unfortunately the studios don’t hand out keys to just anyone.

However the protection has proven to be weak and has been beaten by many applications. Most of these protection applications are based on software called DeCSS. Removing the DeCSS protection and getting the movies to a hard drive is referred to as ripping.

Another problem you'll find - if you're planning to record your movie to a recordable DVD, it simply won’t fit. Currently DVD discs can only contain about 4.7 (actually it’s 4.38) Gigabytes of data. These are generally referred to as DVD-5 (4.7 ~ 5). The movie you purchased might contain a lot more information and many movies are released with up to about 9 Gigabytes of data (DVD-9). It is plain that a DVD-9 movie, will not fit on a DVD-5 disc.

Thankfully, there is simple software available, allowing you to make copies of all your favourite DVDs. Although DVDExploder does not condone the illegal copying of movies for the pirate market, it does not seem fair that an individual should suffer from the deterioration of purchased DVD discs.