|
Many editors don't know it, but recent Media and Film Composer systems (Version 10 and 11) allow you to create DVDs from cut sequences. This offers several important advantages. First, picture quality is much better than that of VHS or 3/4". Second, it's easier to pause, fast forward and rewind a DVD precisely, which makes reviewing cut material more convenient, and DVDs offer instant non-linear access to specified portions of the disk via chapter markers. Finally, DVDs can be played on most recent computers, including laptops, so recipients don't need a deck and monitor to see a sequence.
DVDs are based on a video compression standard called MPEG-2. To create a DVD, your video must first be "encoded" or compressed to the MPEG-2 format. Chapter headings and other organizational elements must then be added. Finally, the DVD is recorded or "burned" onto a blank disk. MPEG-2 encoding is a very processor-intensive task, and on the Avid it operates much more slowly than real time. But once MPEG video has been created and stored on your hard drive, it can be burned to a disk quickly. That means that creating a single disk is much slower than creating a tape. But making a batch of DVDs can take less time than making a stack of tapes. Unfortunately, Avid's DVD implementation is limited and presents a series of "gotchas." The standard Mac DVD burner that comes on high-end G4s doesn't work for all the options offered, and you can't use an Avid-formatted drive to create the DVD file before burning it to disk. Furthermore, you can't insert chapter headings without using a separate application. The documentation provided by Avid does not mention some of these pitfalls and while the Sonic Solutions plug-in that Avid uses to make DVDs seems simple enough, the world of MPEG-2 encoding and multiplexing -- the process of creating a DVD volume -- can be frustrating without proper guidance. In this article, I'll walk you through the process of turning a cut sequence into a DVD and describe the work-arounds you'll need in order to make it work.
The first step in making a DVD is to export your sequence. In the bin, highlight the sequence and choose File > Export, click the options button and select MPEG-2. The Export Settings window will open (Figure 1).
For now, leave the bit rate at the default setting for a high-quality picture. Select "Save As" and label the setting "MPEG-2 High Quality" or something similar, so that you'll later be able to identify that setting as a high bit-rate MPEG-2 export-and-encode. After the setting has been saved, hit Cancel and go to the "Create DVD" options. (If you go straight to "Create DVD" without selecting an export setting first, you will receive a warning that you must select one.) Once an MPEG-2 export setting has been selected, the "Create DVD" window will open, with options and some explanations provided by the plug-in (Figure 2).
In the Function pop-up menu at the top of the window, the first choice -- "Create DVD volume and Write to DVD" -- may seem like the best option, because it enables you to encode and burn in one step. However, the only officially supported drive for this option is the Pioneer S-201 DVD burner. With any other drive, including the Pioneer DVR-A03 or DVR-A04 SuperDrive that is built into G4s, when you insert a DVD for burning, a "Disk is Locked" error message will appear. To get around this, you must do the encoding and burning as separate steps. The second choice in the Function pop-up -- "Create DVD volume on disk" -- is the key. A short summary that appears just below the Function menu explains where the various files will be placed (Figure 3).
These include the raw, encoded files (with .m2v and .wav suffixes), a folder named after the sequence and a subfolder called "DVDVolume." This represents the end result of the encoding and multiplexing process and contains two more folders necessary to burn your disk: the Video_TS folder (Video Titleset) and the Audio_TS folder (Audio Titleset). You may notice that the Audio_TS folder is empty. No worries -- the audio is actually in the Video_TS folder, but the empty folder is necessary for proper DVD formatting (Figure 4).
The last line of information in the Create DVD window tells you how much space you will need for both the encoded files and the exported DVD volume. In Figure 3, the window shows that 26.9 GB will have to be allocated for the two-hour test sequence. Since a DVD can only hold 4.3 GB of data (disks are listed at 4.7 GB but 400 MB is used for initialization), it is obvious that the sequence is encoded at too high a data rate to fit onto a single DVD.
At this point, you will need to make a choice about bit rate vs. quality. The lower the bit rate of your DVD sequence, the less space it will consume, but the lower its image quality will be, and the more likely you are to see artifacts from the encoding process. With a higher bit rate, the quality will be better, but the sequence will take longer to encode and more space to store. Too high a bit rate can cause skipping or stuttering during playback on some computer DVD drives and consumer set-top players. A bit rate of 7.0 is generally good for overall performance, and a bit rate of 6.0 will play back on almost anything without skipping. As with all compressed files, your final image quality depends partly on the resolution of the original file. But even if you start with an uncompressed image, low bit-rate encoding will degrade your image and result in a loss of contrast and saturation.
You will need to set aside a considerable amount of computer time for MPEG-2 encoding. The speed of the process is directly related to the quantity of RAM you have installed and the processing power of your CPU. On a 933 Mhz Power Mac G4, for example, a two-hour sequence will take over 16 hours to encode at the highest bit rate. On newer Power Macs and PCs, the time may be significantly reduced, but you will still need as much as a full day to encode a two-hour sequence. During that time, the computer will not be able to do anything else. Even a 30-minute sequence can tie up an Avid for several hours. The second gotcha with Avid's DVD solution involves drive formatting and file size. Avid-formatted SCSI drives on the Macintosh are usually initialized to the old Macintosh standard called HFS (sometimes called "Mac OS Standard"). As a result, they can't accommodate files larger than two gigabytes. Unless you are creating a DVD from a sequence that's shorter than about 20 minutes, you're going to be creating files bigger than that and you won't be able to use your Avid drives to store the compressed files. Instead, you'll need a drive formatted to Apple's latest standard, called HFS+ ("Mac OS Extended"). You will have to use an external Firewire drive or an internal drive formatted with HFS+. To see how a drive has been formatted, click on its icon in the finder and select File > Get Info > General Information. If you don't have a second internal drive, the system drive is your only choice. Just make sure that you don't fill it up! (PC-based Avid systems running Windows 2000 and XP with FAT32 or NTFS file systems do not have the two gigabyte limitation.)
Because the encoding process takes so long and offers so many options, it's sensible to output a short sequence first and test it before taking the time to create a DVD with your full sequence. You should experiment with bit-rate settings to see how much quality you'll need for your final output. One convenient trick is to play back the encoded sequence from your hard disk before you burn it. This will give you a good sense of the effects of various settings, without the expense and time required to make the disk. On a Mac, you can test the playback of your DVD sequence before you burn the DVD using the player that comes with the Apple Power Mac G4 and OS 9. But in yet another gotcha, you will have to de-activate the MacsBug startup in Extensions Manager and restart before you can launch the DVD player application. Once you open the DVD player application, you will also have to check the box for "Add 'Open VIDEO_TS' menu item to File Menu" on the Advanced Controls tab in Preferences (Figure 5).
On a Windows-based machine, Windows Media Player can only play the .m2v file without audio, but at least you can check the video playback.
You're now ready to burn your DVD. The best way to do this is with Roxio Toast Titanium, which you'll have to purchase separately. Toast allows you to burn all manner of disks and is quite intuitive. Open Toast and select the "Other" tab at the top of the screen and then choose the DVD option (Figure 6). Then simply drag and drop the Video_TS and Audio_TS folders onto the Toast Titanium window (Figure 4). Click Record and insert blank media when the program prompts you to do so. Be sure to let the program verify your disk. (Do not drag the .m2v and .wav files to Toast. These would be used if you were planning to create a DVD with chapter headings using a separate authoring program.)
Burn your short test sequence to disk first. That will allow you to test the playback on a variety of consumer players before spending hours outputting a long sequence. In theory, all players should handle your disk properly, but in practice, a DVD that plays perfectly in one brand of player can fail completely in another. For best results try your test disk on the machine you plan to use for playback.
DVDs created with the Sonic plug-in do not contain index markers or chapter selections. The disk will play automatically as soon as you insert it into a DVD player. To add indexing you'll need a separate application like Apple's DVD Studio Pro. You must prepare your video appropriately, so that DVD Studio Pro can manipulate it. To do this, use the third and final option in the "Create DVD" Functions pop-up -- "Export MPEG-2 and WAV files" (Figure 7). This will create an .m2v file and a .wav file that your authoring program will use to make a DVD with chapters. (The Video_TS and Audio_TS folders are not created). Use of DVD Studio Pro is beyond the scope of this article. It's intuitive, but because it's so powerful and flexible you should be prepared to spend some time learning how to use it. It costs about $1,000 and is available from Apple and Apple dealers.
Apple also supplies a basic DVD authoring program called iDVD with all SuperDrive systems. It will allow you to create a DVD with chapters, but only if you import a QuickTime reference movie exported from the Avid. Unfortunately, it will not recognize an MPEG-2 stream, such as the .m2v file, so it won't work with the Sonic plug-in. This presents some problems, particularly in a 24-fps Avid environment. iDVD doesn't appear to handle 24-fps Quicktime media properly (video on the DVD will stutter), so you'll need to export at 30-fps, which is very time consuming. And you'll have to make chapters by creating a Quicktime reference movie using Quicktime Pro. In addition, iDVD Version 1 does not support the 16x9 aspect ratio. iDVD 2 does, but it runs only in OS X. In general, if you want to create chapter headings, get DVD Studio Pro.
DVD technology is changing quickly and a variety of competing and sometimes incompatible formats are now in use. DVD-R is similar conceptually to CD-R in that disks are cheap and can be recorded once. It is currently the most widely supported format. The SuperDrives found in Apple Power Macs burn only DVD-R disks, and a DVD made on a SuperDrive will play back on most consumer players. For DVD-R media, I recommend Apple, Pioneer or Verbatim disks. I have tried many cheap brands with poor results. If you burn a disk that won't play properly, there's no way to rescue it and you become the proud owner of a $5 coaster. Windows-based machines and external DVD burners for Macs support a variety of other standards, including DVD-RW, DVD+R and DVD+RW, which offer you the ability to erase and re-record a disk, but not all will play back on consumer machines, and software support for these formats on the Mac is limited. If you choose to use one of these formats, be sure to leave plenty of time for integration and testing. DVD+R, for example, is now supported on newer consumer DVD players but may not work on older players. Check the compatibility lists provided by your drive manufacturer. Apple lists the consumer DVD players that can play disks made with the G4 Superdrive at www.apple.com/dvd/compatibility.
If your production has a need for DVDs on a regular basis and you're willing to spend some money for the most efficient solution, you should consider an external burner appliance. These systems take a simple video and audio input and create a DVD using their own high-performance compression hardware. You simply play your sequence out of the Avid to the burner and let it do the rest. This avoids tying up the Avid for hours while you encode. But be aware that "real time" is actually a misnomer for most burners under $5,000: The units will encode in real time, but for disks that are to be played back on consumer DVD players, there is a finalization step that can take three times longer than the initial encode. (The video and audio will play back on the burner that encoded the video without finalization, but the step is necessary if the disk will be moved to another player.) The picture quality from these burners is generally very high, though the final result depends on the settings you select. The options most commonly available are one hour at high quality or two hours at lower quality.
DVDs are a far more director-friendly output medium than tape, because they make it so much easier to review and analyze a sequence. Making them is time-consuming, and you'll probably have to do some experimenting to find a solution that works best for you and your show. But once your director or producer receives their first DVD, they'll probably never want to look at cut material on tape again.
|
