The model for DVD authoring has been similar to that of movie making or music recording-a huge effort to produce one precious, immutable, master disc, which is replicated or duplicated as the final unchanging product.
But it doesn't have to be that way. Imagine re-creating the disc navigation of previously burned DVDs or including several editable versions of a cut for clients. The create-once model is breaking down into a new model in which a DVD is a repository of material that can be reused and even re-edited with new and updated material.
However, this view conflicts with the basic DVD-Video format, which was designed for efficient playback on low-cost players, not for extracting and updating individual elements. As a result, it has been difficult to recover and reuse content from a DVD disc, something video professionals often need in their daily routines. What, for example, do you do with a client who asks you to make just a few changes to a DVD that's been authored at another facility? Recapture original sources, re-edit, recompress, and reauthor the entire disc?
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| Roxio Disc Copier provides a simple interface to copy an entire disc or preview and select a single Title set.
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Professional DVD re-editing relief is on the way. Paradoxically, most development is coming from consumer software applications. So the next time you hurry past the consumer software aisle at your local computer store, you might want to take a closer look. Don't scoff-there are actually some tools video pros can use, and they may support a DVD format many video pros know little about. Until the pro tools catch up, take a look at how these cheap tools can save you gigabytes of time.
There are two main trends: DVD copying tools that can extract selected tracks and elements from a disc, and DVD re-editing formats (OpenDVD and VR formats) that save authoring information on a disc to allow it to be re-created.
To demonstrate how far these approaches have come, I'll examine a variety of DVD applications to deconstruct, extract, and re-edit the contents of DVD discs. DV Contributing Editor Ralph LaBarge of Alpha DVD (www.alphadvd.com) has kindly volunteered his original StarGaze: Hubble's View of the Universe DVD as a test case (www.stargazedvd.com). StarGaze contains a variety of interesting elements, including multiple format videos, a profusion of audio and subtitle tracks, and slide shows.
StarGaze has some uncommon elements that can stress consumer tools, including multilanguage menus and a screen saver slide show with 141 chapters. Most important, StarGaze doesn't have any DVD content protection such as CSS encryption or even region codes, so we can legally access its content without running afoul of the Digital Millennium Copyright Act.
This isn't a story about illegally ripping DVDs. The tools and techniques I discuss assume that you're dealing with DVD content you have the rights to copy. For most video pros, that often means you're dealing with your own content or content your client has the rights to. Unlike the late program DVD X Copy from 321 Studios, none of the tools I'll mention include de-CSS capability.
It seems so obvious: You can see a DVD's contents when you play it and access all of its individual elements-titles and chapters and tracks, menus and buttons-so what's the problem with updating it? This is the nightmare for production facilities requiring small changes to previously authored DVDs. After all, much of video editing is introducing small updates and changes.
However, when authoring DVDs, once you check assets in, you really can't check them out again. DVD is a glommed format-all of the content that seems so accessible when you play the disc is multiplexed, smashed together into the DVD-Video directory format with IFO and VOB files, then split arbitrarily into gigabyte-size chunks.
For professionals, this means that if you ever might want to re-edit a finished DVD, you need to archive all of your original assets and project files. But that's a lot of storage space (much more than will fit on the final DVD), and may not be usable anyway a year later when you've migrated to a different authoring tool. And you still have a problem when a customer brings in an outside disc to be updated.
A more fundamental question is, Why should you have to back up the original DVD project and assets anyway? All of the basic elements are right there-the meticulously compressed video and audio tracks, chapter points, subtitle tracks, menus and button highlights, navigational links and commands. DVD players can access and present all of this media, so why can't DVD authoring tools open up a DVD and present it as well?
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| CyberLink PowerDVD Copy breaks out the individual Titles (and some Chapters) on a DVD so you can select individual audio and subtitle tracks to be copied.
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These days, DVD professionals commonly use simple tools to extract the compressed video and audio assets from the individual VOB files, but not the deeper navigation information.
But a new breed of DVD copying tools can go farther to parse a DVD, copy selected parts of the content, and fix up navigation through the remaining material.
In a parallel development, formats that augment DVD video, such as Sonic's OpenDVD and the DVD VR (Video Recording) format, save additional project data on the disc to enable it to be re-edited. There are still plenty of limits; for example, you still can't reopen an arbitrary disc in an authoring tool and immediately edit a typo in a menu. But there are many steps you can take to deconstruct and reconstruct DVDs.
Although DVD copy tools typically provide mini-viewers to help select the content to be extracted, you can figure out a lot about the structure of a disc using a simple DVD player application such as CyberLink PowerDVD (www.gocyberlink.com; $39) or InterVideo WinDVD (www.intervideo.com; $49 and up).
These applications are designed to optimize your DVD viewing experience by enhancing the video for your display, boosting the audio for your listening environment, and even speeding up playback slightly so the movie finishes before your airplane lands.
But they also provide useful features to help deconstruct the physical design of the DVD by displaying the current title, chapter, tracks, and content formats in the control panels and on-screen displays. You then can use the controls or right-click menus to navigate directly to any title, chapter, and track on the disc. These players also include browser windows that display hierarchical and thumbnail views of the title and chapter structure.
Let's look at StarGaze as a case study; but even if you don't own it, the general principles apply. StarGaze begins with the first play widescreen title and credit sequence in title 9, then jumps to a language selection menu in title 8, and then, if you do not make a selection, times out and jumps to the main movie in title 1. (Notice that these players and DVD copy tools use the DVD specification's terminology of Title and Chapter, even for consumers.)
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| Pinnacle Systems InstantCopy can re-compress and reformat a DVD to fit to a VideoCD, Super VCD, or single-side DVD.
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Pressing the Title menu button jumps to the main menu, which contains familiar options (Play, Chapters, Special Features, Credits, Preview). The first large Title is the main movie, as expected by the DVD Copy tools, and as you click in the Chapters menu, it jumps as expected to the 10 chapters in the main movie. The menus are displayed from chapters in title 2. In fact, browsing the disc's structure shows that titles 2 through 5 follow the same design, each with 26 chapters of still and motion menus. You then can jump directly into them to see that these are the alternate language menus (English, French, German, and Spanish), designed as parallel structures in the four title sets. DVD Copy tools would see these alternate titles as plain video clips.
Previews of other DVDs are in title 6, stored in standard aspect ratio, unlike the widescreen main movie. Title 7 contains a DVD screen saver, with an amazing 141 chapters, each with a random image displayed for 10 seconds. This can cause difficulties for DVD copy tools that try to display the disc's structure in a small window, or tools that use a flat list of all of the chapters on the disc.
Even better, you will find additional content in titles 10 and 11 that is not obviously linked from the main menus. DVD authors need to be aware that although it's fun to author discs with secret Easter egg content that's hidden from access through the DVD's menus, these software players do lay bare the entire structure of the disc's contents.
Once you've understood the content and structure of the DVD, you can use DVD copy software to extract and convert selected portions of its content.
Over the last year, many individual applications were consolidated and bundled into suites of tools for media capturing, editing, and sharing. Amid this consolidation and bundling during summer 2003, DVD copying broke out as a distinct category of standalone applications.
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| InterVideo DVD Copy provides a hierarchical list of titles and nested chapters to copy, extract to DivX MPEG-4 files, or merge multiple discs into a compilation.
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Sonic's professional and consumer DVD authoring line has been expanded to a full digital media suite with its acquisi-tions of the Veritas RecordNow and now Roxio products (www.sonic.com). CyberLink and InterVideo have expanded from their DVD player roots to add recording and editing tools.
On the consumer side, there are some usable tools for pros. Roxio's venerable Easy CD Creator disc burning application has grown into the Easy Media Creator 7 suite (www.roxio.com; $99).
Pinnacle Systems's Studio video and DVD applications have been joined by its Instant line of disc, photo, and video burning tools, and then merged into the new Studio Media Suite in fall 2004 (www.pinnaclesys.com).
It's remarkable that DVD extraction capabilities are being lead by the consumer market.
To make only a backup copy of a DVD or CD, you can use a simple tool such as Roxio Easy DVD Copy (www.roxio.com; $49). As with most of these applications, it starts with a basic interface for copying an entire disc and then offers an Advanced button to specify more options. It attempts to provide helpful copy options by separating the DVD content into the main movie and a list of remaining extras, with all of the additional titles sorted by length (with StarGaze, this jumbles the menu titles in with the preview and bonus titles). You then have the option to copy the entire disc or only the main movie and the main audio track (but not selected titles and tracks). It also can copy to or from a disc image or DVD-Video files on hard disk.
If you want more control over which content is included on the copied disc, CyberLink PowerDVD Copy (www.gocyberlink.com; $39) allows you to preview and select individual titles and tracks. You can set global options, including removing any audio or subtitle tracks present on the disc that are tagged with specific languages supported by the DVD specification. PowerDVD Copy also provides more control over the compression quality with a slider to adjust the video quality, and therefore the size, of both video clips and menus. However, the interface attempts to separate menus and titles, and lists chapters as multiple instances of the same titles, so complex titles such as StarGaze generate a confusing list with many listings of the same title and some chapters omitted.
Beyond simply copying portions of a DVD, tools such as Pinnacle Systems InstantCopy 8 ($29) can convert and recompress DVD content as needed to fit on VideoCD, Super VCD, or DVD (e.g., to transfer from a dual-layer replicated DVD-9 to a single-layer recordable disc). You also can set the video aspect ratio and remove any DVD spec user prohibitions (for remote control menu or searching functions, such as preventing skipping past the first play copyright notice). InstantCopy can recompress the content automatically, or you can choose between High Quality and High Speed options. You also can recompress or exclude the DVD menus and exclude any DVD-ROM content.
But why copy only one disc? InterVideo DVD Copy 2 (www.intervideo.com; $49 and up) extends copying in two ways: extracting selected content to files on hard disk (in MPEG-1, MPEG-2, or DivX MPEG-4 format), and merging contents from multiple discs. It provides a hierarchical list of titles and nested chapters to preview and select. You can compress to fit to the target disc or span the copied material across multiple discs.
You can see where this trend is heading: tools that provide the ability to extract arbitrary selections of content from multiple DVDs, and then combine them into new compilations in a wide variety of formats.
This approach is demonstrated by Ahead Nero Recode 2 (part of Nero 6 suite; www.nero.com; $99), where even the name demonstrates its focus is beyond simple DVD copying to also extracting and transcoding content, in Nero Digital (MPEG-4) format. You first import one or more DVDs, and Nero Recode scans the disc to analyze the structure and compression statistics. You then browse the disc to select the titles to import into your project.
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| Nero Recode can create compilations by importing titles from multiple discs, trimming clips by chapters or frames, setting recompression quality, and selecting audio and video tracks - before exporting to DVD or transcoding to Nero Digital MPEG-4 format.
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Nero Recode helpfully tries to organize the DVD titles automatically into menus, movies, and extras. However, with StarGaze, this resulted in the menu chapters being broken out separately as a long list of tiny clips.
You then can refine the assembled content from each title: trimming the title by chapters or even exact frames, and selecting audio and subtitle tracks. When extracting to MPEG-4, you also can crop and resize the frames. Recode provides explicit control over how each element is recompressed, and you can browse and select which DVD-ROM data files to include in the copy. Because you can do significant violence to the integrity of the DVDs that you import by deleting titles and menus that are part of the navigational structure, Recode provides explicit options for removed titles: you can specify a placeholder image, and keep or strip out the associated audio and subtitle tracks.
What about Mac support? While Apple's focus with iDVD and DVD Studio Pro is on authoring new DVDs from edited and captured content, a profusion of commercial tools has developed on the Windows platform to expand the trend of copying and repackaging material from existing DVDs.
These tools have developed from the active competition on the PC, among three different market segments: disc burning tools (e.g., Roxio and Ahead), traditional DVD authoring tools (e.g., Pinnacle Systems, Sonic, and Ulead), and even DVD player applications (e.g., CyberLink and InterVideo).
On the Macintosh, these segments are filled by Apple's built-in OS X utilities, digtal media tools, and DVD Player application. Commercial products-such as NewTech Infosystems (www.ntius.com) Dragon Burn and Roxio Toast, which provide alternate suites for disc burning, authoring, and backing up-don't have the depth of control over reformatting content that the PC tools possess.
A quick note on compression quality with these tools: These applications used to default to providing faster encodes at the expense of higher quality, and the result was visibly blocky video. More recent releases of these DVD tools provide more control over compression quality and produce satisfactory results at the higher-quality settings. However, the typical use for these disc copying tools is to shrink a lot of material onto a single disc, so you can expect the video to be degraded accordingly. Converting to VCD will take longer, and the results will be adequate at best, as expected with MPEG-1. These tools provide options to exclude portions of the disc from the copy in order to leave more room for better-quality compression.
These DVD copy applications demonstrate different attempts to provide convenient and friendly interfaces that still reveal a couple layers of the DVD-Video formats (Titles and Chapters, Tracks and Languages). At the other extreme are freeware tools such as IfoEdit and VobEdit that expose every gory detail of the DVD specification down to the MPEG data streams (see www.videohelp.com). There are also categorically different professional tools, such as Trai Forrester's TFDVDEdit (www.tfdvdedit.com; $1,295), which drills way down into DVDs and enables powerful control of reauthoring.
Meanwhile, Ahead is focusing Nero Recode even more on extraction of content for reuse in MPEG-4 format. Ahead's Udo Eberlein explains: "We see Recode/Nero Digital as a very important component of our bundle, especially in the near future as the need for streaming video over the Internet, MPEG-4 playback on set-top boxes, DVRs, phones, and consumer electronics devices sales grow. We have had over 45 million downloads of Recode since December 2003, which underlines the apparent need for high-quality compression (requantizing and transcoding) applications. As already announced, H.264 is definitely on our roadmap, and we expect a significant video quality improvement with this next-gen codec very soon."
In this new model, DVDs become convenient, playable repositories of content: discs that can be extracted, converted, reused, and reauthored into compilations in various other formats. Imagine the implications when using DVDs for organizing digital dailies, or fostering client-requested updates, all on one disc.
Although issues such as transcoding speed, video quality, and patched-up navigation may be less than optimal for professionals, these consumer tools still provide tremendous flexibility in reusing material that once seemed locked away in the inscrutable DVD format.
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Reauthoring Recordable DVDs
Copying and extracting content from DVDs is only a partial solution for the more fundamental need to re-edit the contents of a DVD.
Why can't we just open up a DVD as a project in our authoring tool so we can edit the clips, menus, and navigation? This possibility seems so tantalizingly close with DVD copying tools because they can access much of the structure of a disc.
However, a DVD still contains the composite images used to display menus and subtitles, but the individual elements used to compose them are no longer available as discrete elements. The layers of media that comprise the menus-background and foreground, graphics objects and text, solid and translucent blends-all are flattened into the final menu image that is stored on the disc. Subtitle text is rendered into overlay images in a similar fashion. As a result, you can recover the menu highlight graphics and button locations from a DVD, but you can't take the next step of repositioning the button elements against the background or editing the menu text.
In order to be able to re-edit the elements used to compose a DVD, then, you need access to the original project file and the associated assets used in the project (i.e., images and text). You don't need to keep an extra copy of the large video and audio clips because they are accessible from the final DVD.
But why back up your projects separately? Why can't the DVD itself be the backup? Wouldn't it be the best of both worlds if a DVD could save project information directly as additional DVD-ROM data files? Then you would have a fully playable DVD, plus the built-in capability to reopen and reauthor its contents.
The need for this kind of solution arose directly from the development of set-top DVD recorders, which obviously had to be able to record material to a disc in multiple sessions, as well as edit and rerecord to a DVD-formatted disc (i.e., DVD+RW). This is where the VR (Video Recording) DVD formats originated, with the bonus of exchanging re-editable discs between the set top and desk top. Similarly, Sonic Solutions developed the OpenDVD format to support re-editing discs in its authoring tools.
-VR Format
In keeping with the tradition of multiple confusing DVD formats, there are two very different variants of VR formats: dash (-VR) and plus (+VR). Although these formats arose from the two different format camps to permit real-time recording and re-editing, they were designed very differently.
DVD-VR supports relatively plain text menus that are dynamically generated in the player. As explained by Andy Parsons, senior vice president of Pioneer Electronics, the -VR format was designed not as a playable DVD-Video disc, but as a storage format from which you could edit its contents:
"DVD-VR is intended to make editing easy, but at the expense of DVD Video's complex navigation layer. This means you can do easy editing of material, but you give up playback compatibility with the majority of installed DVD Video players (other than those labeled RW Compatible, which many newer models now support). Menus are constructed by -VR-compatible recording/playback devices, sort of like a virtual menu; there are no DVD-like menus recorded on the disc."
To sum up, players and software labeled "RW Compatible" will recognize and play back -RW physical discs, recognize and play back -VR format recordings on DVD-RW media, and recognize and decrypt CPRM encrypted content in -VR mode.
Check out www.rwppi.com/compati for a list of DVD players and their compatibility with DVD-R/DVD-RW discs recorded by the DVD-VR format.
Besides supporting the -VR format, dash recorders also provide the option to record directly in DVD-Video format, typically for transferring content to a DVD-R disc that then can be viewed on any player.
+VR Format
In comparison, the +VR format is a variant of DVD-Video. "A disc created to the +VR spec (by a set-top recorder or a PC drive with appropriate software) is DVD-Video compliant," says John Main, system architect in Hewlett Packard's Optical Storage Division. "The +VR spec was developed to allow real-time recording/appending/editing on +RW media, and still maintain a disc that is DVD-Video compliant, so as to allow playback in existing players."
These discs can contain graphical menus with thumbnails of linked clips. However, "the +VR spec (since it is a real-time recording format) has limits on the menu structure and navigation flow you can create on a disc. For example, you would not be able to create a recording in real time (i.e., from a set-top recorder) that has the flashy motion backgrounds, animated menu buttons, background audio, etc. that you see on a Hollywood title, or titles that you could create with some of the existing software authoring tools." See www.dvdrw.com for more info from the DVD+RW Alliance.
Sonic OpenDVD
Sonic Solutions has gone its own way to develop a format that enables DVD rerecording. Sonic describes the OpenDVD format as "a technology for creating DVD titles that include all of the necessary information that allows them to be re-edited, revised, and changed over time." OpenDVD adds additional data to a DVD-Video disc, stored in the DVD-ROM zone, that includes project and navigation information, plus additional elements, including menu graphics, backgrounds, and button art (see www.sonic.com/opendvd).
"This feature is critical for consumers," says Charles Wiltgen, MyDVD product manager at Sonic Solutions. "We've seen that OpenDVD removes the fear and anxiety that users would otherwise have if they couldn't edit or update their disc to fix things like typos, to add new episodes, etc."
Sonic has supported OpenDVD in MyDVD ($49 and up), and in the professional DVD Producer (starts at $1,999) application, but it is not yet supported in the new release of the midrange DVDit 5 ($299; see the review on page 50). "OpenDVD is an extremely important part of our prosumer and professional product line," says James Manning, DVD product marketing manager at Sonic. "DVDit will include OpenDVD in the next major revision."
The new release of MyDVD 6, available in fall 2004, can import clips from DVD-Video, +VR, and -VR discs. It parses the DVD-Video IFO files to extract and span clips across the VOB files to allow users to logically browse the disc contents. MyDVD 6 also supports +VR disc export. "The VR formats [both -VR and +VR] re-create disc navigation from scratch with every modification to the disc," says Charles Wiltgen, "so for those formats, we support VR-based import, editing, and authoring. For the DVD-Video format, OpenDVD provides a more complete disc editing experience since it preserves the look and feel of the DVD as well as the navigation."
Wiltgen continues, "For professionals, OpenDVD allows users to change DVD content without requiring reauthoring from scratch, making DVD an even more suitable medium for client approvals. Additionally, because all assets are stored on the DVD, ready for re-editing, the DVD itself can also serve as the project backup for exceptionally easy asset management."
Ulead DVD MovieFactory
Support for the VR formats in DVD authoring tools was originally driven by the drive manufacturers, who needed to bundle tools with their products that supported the associated VR format. Some authoring tools can import discs in one or both of the VR formats as a new project, or at least import assets from a recorded disc. Tools such as Nero Vision Express 2 can import or create DVDs in +VR format or record in real time to +VR, ready to play and edit further on a set-top recorder.
Ulead has provided extensive support for importing and exporting the VR formats in DVD MovieFactory 3 (www.ulead.com/dmf; $49). This tool goes beyond importing the contents of a disc (which requires copying all of those megabytes to hard disk), to actually re-editing a rewritable RW disc in place, without needing to cache large files through the hard disk.
As described by Travis White, product marketing manager of Ulead Systems, this can involve tricky management of the available free space on the disc: "One benefit -VR has is that it can have multiple playlists, so there can be various sequences of the same material being played. Also, if there is a blank space between data (such as if you delete a title), then -VR can use that space and combine it with other free space to accommodate a longer new video. The seamless play is achieved by a buffer in the player that is part of the -VR specification for players. Some -VR set-top players have the ability to sniff out a thumbnail from the different titles and display a thumbnail menu, but that is a function of the player, not the disc itself."
Ulead sees the flexibility of the +VR format as ideal for consumers who can author DVDs on rewritable media that are fully playable, and yet also can be easily updated in place to add new material. In this model, a DVD disc is no longer the final archive of a polished production, but instead is a dynamic, transitory view of a work-in-progress. Granted, this is a little dangerous because the final disc is also the editable project, so it might be a good idea to make backups before re-editing discs in place.
Says White: "If you have a -VR recorder, stick with that format. If you have a +VR recorder or no recorder at all, do the +VR format so you can experience the graphical menus just like DVD-Video."
DVD MovieFactory extends the +VR format by including its own project file on the disc to provide more detailed information and assets for the DVD menus and structure. It's interesting that the current version of Ulead's higher-end DVD Workshop application does not re-edit discs and does not write to the VR formats.
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Associations and Info
Alpha DVD - Ralph LaBarge
www.alphadvd.com
DVD+RW Alliance
www.dvdrw.com
StarGaze: Hubble's View of the Universe
www.stargazedvd.com
Manifest Technology - General DVD Info
www.manifest-tech.com
RWPPI - RW Products Promotion Institute - DVD-R/RW Disc Compatibility
www.rwppi.com/compati
Software
Ahead Software
Nero Recode 2
www.nero.com
CyberLink
PowerDVD, PowerDVD Copy
www.gocyberlink.com
DVD Authoring
Software Gallery
www.manifest-tech.com/links/dvd_sw_gallery.htm
InterVideo
WinDVD, DVD Copy 2
www.intervideo.com
Pinnacle Systems
InstantCopy 8
www.pinnaclesys.com
Roxio
Easy Media Creator 7
Disc Copier
www.roxio.com
Sonic Solutions
MyDVD, OpenDVD
www.sonic.com, www.mydvd.com
Trai Forrester
TFDVDEdit
www.tfdvdedit.com
Ulead
DVD MovieFactory
www.ulead.com/dmf
Video Help
IfoEdit and VobEdit
www.videohelp.com