The Many Faces of FireWire
The Many Faces of FireWire
If you thought FireWire was merely a thin cable technology that did little more than connect a camcorder to a computer, you're in for a few big surprises. As of this writing, you can connect more than 1,000 devices via FireWire--computers, laptops, video decks, still cameras, audio mixers, hubs, removable drives, DAT recorders, and CD/DVD writers--to both professional- and consumer-level workstations. And according to industry estimates, more than 200 million FireWire-equipped products will have shipped by the year 2003. Although many of you may be familiar with FireWire as a simple interface standard, there's some remarkable aspects to this technology you might have missed.
Target Disk Mode
Using Your Camcorder for TV Previews
1394b: The Next Generation
Target Disk Mode
One of the easiest ways to connect two FireWire computers and share files is with a simple system configuration called target disk mode. This feature is available only on Macintosh computers, but target disk mode theoretically allows any computer with a FireWire port (the target computer) to be used as an external hard disk. The target computer appears as a hard disk icon on the desktop of the other machine--the host computer. For example, you could use this feature to mount your PowerBook G3 on your G4 workstation as an additional volume--like a portable hard disk--that can be accessed with full read/write permission, just like any other storage device. Target disk mode works on any FireWire-equipped PowerBook, iBook, Power Mac G4, G4 Cube, or iMac with Firmware version 2.4, FireWire 2.3.3 drivers, and Mac OS 8.6 or later.
To successfully execute this operation, first be sure that your target computer is shut down and that you've removed all other FireWire devices from both computers prior to activating target disk mode. The host computer does not need to be powered down, but you must connect the two computers with a 6-pin-to-6-pin cable before starting. Apple also recommends that you connect the computers to AC power.
Figure 1 A quick way to connect two Macintosh computers is by using target disk mode--a feature of the Mac OS that lets a host computer mount the internal hard drive of another FireWire computer simply by using a six-pin cable.
As you boot up the target computer, immediately hold down the T key and keep it down until the monitor displays the FireWire logo. Once the target computer is up and running, its internal hard disk will appear as an icon on the Finder desktop of the host computer. Now, you're ready to copy files to or from that volume. Note: The host computer cannot access peripherals attached to a target computer, only the internal hard drive.
When you've finished transferring files, you can simply drag the target computer's icon to the Trash (or select Put Away from the File menu) and disconnect the 6-pin FireWire cable. Then you can press the target computer's power button to turn it off. Don't attempt to reconnect any FireWire devices until after you have disconnected the two computers from each other or have stopped using target disk mode. If you unplug the target computer and then try to reconnect it to the host, you may find the hard disk icon does not appear on the host desktop. In this case, just check the cable connections and restart the host computer.
Target disk mode isn't a true networking configuration (only one computer is fully operational), but it's an incredibly handy way to quickly connect to another computer and transfer files between internal hard disks. For Macintosh users, target disk mode can be an indispensable tool in the moviemaking process.
Among the first special effects techniques ever invented for the cinema, stop-motion photography is a unique discipline that brings everyday objects to life by changing the position of elements over a period of time. It's a painstaking effort, but thankfully, FireWire has breathed new life into older stop-motion methods. For example, you can now connect a DV camcorder directly to the FireWire port on your computer and judiciously pick frames of video to import into your moviemaking applications. As tired a phrase as it is, it's truly a revolutionary advancement.
New video frame-grabber software, specifically a shareware program called FrameThief, can capture frames one at a time from almost any FireWire webcam or camcorder. FireWire-equipped digital still cameras also work with FrameThief, which imports pictures immediately and lets you review them in loop cycles so you can instantly reject poor shots for better images. Previously, animators had to guess if the film they shot had recorded the movement accurately. Today, they can preview each frame and make subtle adjustments before capturing the final image. You can download a free copy of FrameThief at www.framethief.com or use the version on the DVD that's included with FireWire Filmmaking.
Figure 2 FireWire frame grabber FrameThief is a video frame grabber for stop-motion animators working on the Macintosh platform. Offering a rich tool set for high-quality animation, FrameThief is compatible with nearly all FireWire capture devices--from Webcams to digital still cameras and DV camcorders. The program is based on a plug-in architecture that supports higher-end cameras to produce HDTV or film-quality animations on a relatively small budget.
A word of warning: If you are using a digital camcorder, make sure you lock the automatic exposure and manual white balance settings to prevent the camera from making adjustments that can change the lighting and introduce tiny fluctuations from frame to frame. Stop-motion relies heavily on persistence of vision to create the illusion of movement, so any changes in the variables of your subject, the set, the lighting, or the camera, will reveal shifting details in the final sequence and spoil the magic. The automatic features of a DV camcorder can be detrimental to this process.