It's still alphabet city in DVD authoring land, as content providers and end-users—already baffled by the +/-R/RW format wars and their recent, no less baffling detente—try to sort out the differences between +/-VR and OpenDVD. These formats are designed to give users a method of recording and editing that will allow rewritable DVD to replace VHS as an all-purpose re-usable and appendable video recording medium. No longer will a new DVD need to be burned if the user wants to edit content. Sounds simple enough, and it would be if things were standardized around a single format. But, as has always been the case with writable DVD, no such luck. Users must contend with multiple formats and media, as well as different physical and logical writing methods.
Originally designed to provide more flexible and fluid writability and rewritability in set-top, TV-attached DVD recorders, DVD-VR was the first format to emerge. DVD-VR enabled a recorder to write video to disc in real time, a feat that was impossible to achieve under the DVD-Video spec. Before DVD-VR, to write a playable DVD, parameters and navigational information for the complete set of video objects to be included on the disc had to be set before writing began. Because that information is unknown as new video is streamed, recording video to DVD "live" in DVD-Video-compliant fashion was impossible. DVD-VR supplied alternative ways to incorporate that information. DVD-VR also allowed users to edit recorded video, delete unwanted segments, and modify and customize playlists. At the time of DVD-VR's debut, desktop DVD recording was primarily a professional author's medium, used for making check-discs to test compliance and playability before sending a disc for replication, and DVD-R was the only game in town. So the kind of applications DVD-VR made possible weren't really relevant to desktop DVD recording as it was then defined.
The intervening years have brought not only additional formats—DVD-RW, a rewritable extension of DVD-R, and two competing standards, DVD+R and DVD+RW—but also a broad base of home and home office users to DVD recording, and with them a broader range of applications and expectations. With this expanded user base comes, the DVD+RW camp in particular believes, the expectation that desktop DVD recorders, like their set-top counterparts, should also offer the facile rewritability of VCRs. Enter DVD+VR, a video recording format analogous to -VR, but designed specifically for use with plus-format drives. Enter as well OpenDVD, a writing method designed by DVD authoring software market leader Sonic Solutions for use with their ubiquitous entry-level authoring tool, MyDVD.
And then there were three. And as with all these multi-format DVD debates, beyond the relative advantages and disadvantages of each format, a nagging, underlying question always seems to linger: If all these formats serve more or less the same purpose, why have more than one? But since that's not up to us as users (especially since the recent profusion of "multi-family" drives means users will never really get the chance to choose their favorite), a more relevant question emerges in the migration of these "application formats" from TV to PC: Do they really belong anywhere but the living room? What can these formats (the VRs, anyway), designed to compensate for the shortcomings of TV-attached recorders, possibly do for the PC recording space, which doesn't share the same handicaps?
Inevitably, the answer for each format is slightly different. So let's begin with a look at each format and its pros and cons.