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DVD Authoring on the Macintosh
Created: September 17, 2001
Revised: June 1, 2002
DVD authoring is a hot, new Macintosh capability that enables you to create your own interactive DVD project right on your G4 and burn it to a DVD disk. Then the disk can be used in any of the tens of millions of DVD set-top players and computer DVD drives currently in circulation.
The projects you author can be extremely simple. You might enable users to access various videos and slide show choices from one of a number of pre-made backgrounds (iDVD). Or, maybe, you might enable a DVD disk to open automatically, display a splash screen, play a video, and stop when completed (DVD Studio Pro).
Your project can also be sophisticated and interactive. It can utilize custom menus with buttons, multiple video angles, multiple audio tracks, subtitles, and scripts (DVD Studio Pro). Buttons within your DVD can be linked to a URL on the web or elsewhere (DVD Studio Pro) or to text, data, and programs, on other parts of the DVD (Toast Titanium and DVD Studio Pro).
Apple's breakthrough technologies, including the PowerMac G4 with the built-in SuperDrive, iDVD, and DVD Studio Pro Drive have made this possible. And if you already have a G4 without the SuperDrive, you can replace you current internal drive with the same Pioneer mechanism that is the SuperDrive or purchase an external FireWire drive that contains it.
Apple is bringing the DVD authoring revolution to the masses.
Then and Now
Prior to Apple's introduction of the SuperDrive in January, 2001, it cost $5,000 just for the mechanism to burn DVDs, not to mention the price of the computer and related hardware and software. Today, you can do it all on a new (Quicksilver) PowerMac G4 for $2299 or the new iMac for $1,899!
DVD Formats
What is DVD anyway?
Some associate DVD exclusively with video, but that's only part of the package. Others try to make sense of an acronym. At one time the letters "DVD" stood for "digital video disk" and later "digital versatile disk," but the format has evolved to such an extent that, as with VHS, the letters no longer stand for anything meaningful. DVD is just DVD.
There are several DVD flavors (or "logical formats," to use a more technical term).
The grand underpinning of all of them is DVD-ROM, which is a data format somewhat similar to CD-ROM, except that it holds from 7 to 25 times as much data. All applications, installers, data, graphics, and whatnot that can be delivered on CD-ROM can just as easily be distributed via the larger capacity of DVD-ROM and can be accessed with a computer that has a DVD-ROM drive. And all computer DVD-ROM drives, by the way, will also read CD-ROMs; they are backward compatible.
But the designers of DVD-ROM realized that data storage alone was not enough to move this technology to the forefront. Hence DVD-Video, the DVD format many of us are most familiar with. A creation born of pure self-interest, DVD-Video began as an effort by the film industry to convince drive manufacturers to develop a digital alternative to VHS. To do for video, what the compact disc did for audio: provide playback of higher quality, enable easy replication and distribution, and raise prices while lowering costs. And they succeeded. But by the time the DVD-Video specification was completed, the computer industry had also jumped into the mix bringing along its knowledge of interactivity.
DVD-Video is built upon the foundation of DVD-ROM, enabling a potentially powerful marriage for content providers in the form of a hybrid DVD: part DVD-ROM, part DVD-Video. Material supporting DVD-Video can reside on the ROM side of the tracks and be accessible to users who place the disk in a computer's DVD-ROM drive.
But wait; there are still other DVD formats to mention.
DVD-Audio for high quality audio (better than CD-Audio) is just starting to appear on the market. And DVD-VR, DVD-AR and DVD-SR (none of which you need to bother yourself with now) are all on the drawing boards.
For the purposes of this discussion, we will be focusing on DVD-Video and DVD-ROM.
DVD Physical Formats
To potentially confuse matters further, there are also various physical formats for the media that goes into a DVD drive. The most common format comes on a 12 cm disk, which looks like a CD, but holds 4.7 billion bytes (4.38 gigabytes) of ROM data or about two hours of DVD-Video data. This disk, often referred to as a DVD-5, will be recognized by all Mac and most other DVD drives.
To burn a DVD on your SuperDrive (and thereby create a DVD-5 for others to use), you need to purchase a recordable disk, known as a DVD-R (analogous to a CD-R). Apple is agressively pricing these disks at $5 each.
MPEG-2 Encoding
DVD-Video requires MPEG encoded video, and in the US and Canada (which use NTSC video), it must be MPEG-2. MPEG-2 is a compressed format that plays back at a variable rate of between 1 and 9.8 megabits per second (Mbps). A DVD player accommodates data rates within this range. This bandwidth is much wider than the Internet pipeline that almost all folks have (an expensive T-1 line, for instance, runs at only 1.4 mbps; DSL is usually slower, often 384 kilobits per second).
When the fiber optic infrastructure is completed and the trunks jump off the curb to each home and business, maybe we'll be able to stream everything live off the Internet at a normal image size and with excellent quality. But that appears to be a long way off; maybe 10 years. DVD is going to be the video distribution medium of choice for some time.
Prior to the introduction of DVD Studio Pro, one of the major obstacles in DVD authoring was encoding the video into MPEG-2 format. Software encoders existed but were painfully slow, requiring 20, 30, 40 or even more times the length of the source video content to complete the task. Hardware encoders were more efficient, but significantly increased costs and system complexity.
What Apple ingeniously did, was develop a way to utilize the power of the G4 processor, its Velocity engine, and multiple processors to eliminate the hardware costs and dramatically speed up the encoding process via software. The new high-end G4s encode MPEG-2 (from a QuckTime file in DV format) at about a 1-to-1 ratio, or as is said in the business, "in real time." This is an astonishing breakthrough.
iDVD
The easiest way to create a DVD is with iDVD. It ships pre-installed on G4s that contain the SuperDrive. iDVD employs an elegant and simple drag-and-drop interface. You can master all its features in a few minutes. And with iDVD you do not need to (and should not) encode video assets in MPEG-2 prior to using the program. iDVD does this encoding in the background when you burn the finished project.
iDVD is a terrific tool for quickly making neat and simple DVDs. But to enable the full capabilities of the DVD specification you need a full-featured professional authoring tool, namely DVD Studio Pro.
Tapping Into the Potential
What is the full potential of DVD Authoring? Developers are just beginning to show aspects of it.
I recently picked up the DVD release of "Thirteen Days." The film stars Kevin Costner and, of course, deals with the 1962 Cuban Missile Crisis. The DVD was developed by New Line Home Entertainment under it's "infinifilm" branding, http://www.infinifilm.com/intro.html. In addition to the high quality of the video playback, which you would expect on a DVD, the developers created an alternate film presentation with clickable overlays that jump you to interviews and other relevant source material. This material and more is also accessible within menus that link you to biographies, documents, historical information as well as information on the creation of the film.
Models like these will help you develop ideas for authoring your own DVD Studio Pro project.
Planning and Preparing Your Project
It helps to have a clear idea of the what you are trying to convey and how you might do it before you begin authoring. Then you can go out and create, collect, re-purpose, and/or acquire assets for your project. These include your primary video tracks with associated audio streams, any additional language or audio tracks, additional camera "angles" (if, for instance, you're shooting a medical procedure or maybe a rock concert), still and/or motion menus (composited video), and still images for slide shows.
Then you will need to encode your video into MPEG-2 fomrat and make sure to separate out the audio into its own separate file. MPEG-2 encoding is accomplished via the QuickTime MPEG-2 extension that is installed together with DVD Studio Pro. When you export your video as MPEG-2 (via Final Cut Pro, iMovie, QuickTime, Premiere or another QuickTime-compliant program), you will be able to separate the video and audio streams. You will also be given a choice with regard to the encode rate, somewhere between 1.0 and 9.8 mbps. Basically you want to be in the 4 to 6 range. Too low and you get poor quality video, too high and you don't leave enough overhead for some computer DVD players.
What rate should you choose? A general rule of thumb would be that you can use the default (middle) setting if the total amount of video is an hour or less. Beyond that, adjustments may have to be made, especially if your audio has not been compressed (e.g., if it remains as an .aif file). We now enter the realm of "bit budgeting," where the maximum 9.8 mbps bit rate for DVD must be parsed out among the size and length of your video and audio streams, and the lighter components of graphic and subtitles.
DVD Studio Pro ships with a certified Dolby Digital encoder, A.Pack, which easily allows you to compress your bandwidth-busting (1.6 mbps) uncompressed audio into a high-quality Dolby digital format.
In addition, if you need to create subtitles, you can use "Subtitle Editor," also included with DVD Studio Pro. Before using this application I recommend you compress the video into a small size suitable for the web, to grease the program's skids. The end result of Subtitle Editor is a special file containing the subtitle information in a way that DVD Studio Pro can use. It does not contain the rough video you used.
Authoring
So now you're about ready to author.
First it helps to develop a storyboard or design of your navigation and flow. Then use DVD Studio Pro to put it together.
The basic elements of DVD Studio Pro are tracks, menus, slide shows, and scripts.
Tracks have a different meaning than in Final Cut Pro or some other programs. A track in DVD Studio Pro refers to a collection of one main and various alternate video angles, subtitle streams, audio streams, markers and stories (collections of markers).
Menus consist of still images (with or without layers) and composited video. Buttons can be overlaid on the menus.
Slide shows contain still or video images and associated audio.
Scripts enable programming commands for navigation, randomization, and other actions.
Learning DVD Studio Pro is not hard, but does takes a little time. The tutorial provided with the program is an excellent place to start.
Once you have created a project in DVD Studio Pro you can use it as a template for similar projects; just change the assets. You also can purchase pre-built templates to save you time and give you ideas.
DVD Studio Pro and the PowerMac G4 are an exciting new combination in the hands of a content creator. When you've completed your project, you can burn one-offs for a small audience. For larger distribution you can prepare your material for replication in large quantities.
If you have questions on DVD authoring or related topics, just let me know.
Fred Balin
3790 El Camino Real, #2005
Palo Alto, CA 94306
650-565-8120
info@macresolutions.com
©2002,
Fred Balin, MacResolutions
All rights reserved.
Apple, Mac, and Macintosh are registered trademarks of Apple Computer, Inc.