macdevcenter.com
oreilly.comSafari Books Online.Conferences.

advertisement

AddThis Social Bookmark Button

Making Movies with the Apple iSight

by Derrick Story, author of the Digital Video Pocket Guide
07/01/2003

By now you've probably iChatted with all your buddies and are wondering what you can do next with the iSight. As I explained in the weblog, Want to Do More with the iSight than Chat?, this little "cheese grater" of a videocam packs a lot of potential beyond serving as a simple webcam.

The iSight is a well-designed autofocus camera with a fast f-2.8 lens that focuses from 50mm to infinity. But what makes it so powerful is that its FireWire cable plugs into years of Apple QuickTime development lurking within your Mac. In my view, QuickTime is an underrated technology. And I think lots of people are going to discover QuickTime's versatility thanks to this $149 gem of a camera.

In this article I'll show you how to use the iSight with some very inexpensive QuickTime-based software to create top-notch video presentations. You can use these techniques to author something as simple as a video postcard to share with friends and family, or as sophisticated as an interview using three-point lighting -- the same set up that pros use for their projects.

Getting Your Tools Together

Up until now, tools for digital media projects were often expensive and had a sizeable learning curve to master. But thanks to the iSight's simplicity, you can pull together the tool set for these projects quite inexpensively. Here's my recommend list:

  • The iSight a/v cam for capturing full motion video, and in a pinch, audio too. $149 US.

  • QuickTime Pro for managing the media you record to your hard drive. The Pro version allows you to edit and manage tracks. $29.99 US.

  • QuickTime Broadcaster enables you to use your iSight for streaming video over the Internet. But you can also use it to record directly to your hard drive. Free download.

  • Griffin iMic USB audio interface that enables you to use a separate external mic in conjunction with the iSight for better audio recording. $35 US.

  • The Digital Video Pocket Guide provides you with a handy reference for lighting and audio, plus contains lots of pro tips to help you squeeze the most from your iSight. $14.95 US from O'Reilly, and $10.47 US from Amazon.

  • Apple PowerBook or iBook for your workstation. The faster the better. You can use a desktop machine too, but they are more difficult to lug around.

For many of your projects you can use the iSight attached to your Mac as you would for web conferencing. But for interviews and movie making you'll want to attach the camera to a tripod. I recommend a "quick release" model that makes it easy to attach and remove the iSight.

Use the iSight adapter with the flat plate on the bottom. You can push the tripod mounting post up through the opening and secure it with a tripod adapter bushing that can be purchased at any photo store for less than a buck. Now the camera can be securely attached to the tripod for filming (see Figure 1b).

Photo of iSight camera. Photo of the iSight mount.

Figure 1a and 1b. By using the supplied adapter that comes with the iSight, you can attach the camera to the quick-release post of a tripod for easy mounting.

Since the iSight has a good automatic light balancing system built in, you can use just about any continuous lighting source to illuminate your subject. If you don't have a video light already, a quick trip to the hardware store for a couple of shop lights will do the trick nicely.

The main thing to remember is not to mix your light sources. Stick with daylight (from window) or tungsten if you can. But if you mix the two, or add fluorescent lighting to the scene, the iSight (or any other camcorder) will have difficulty correctly balancing all those different sources.

Getting the correct lighting.
Figure 2. A visit to your local hardware store can produce decent lighting for your iSight movies. Get the brightest light you can. Then, if possible, hop over to the photo store for a reflective umbrella. This accessory will diffuse the light for more pleasant skin tones.

Pro Tip: For those of you shunning artificial lighting, one of the most common problems in natural light shooting is backlighting. If you want to know how to identify and deal with it, download this PDF on how to cope with backlighting from the Digital Video Pocket Guide.

The next thing you should consider for interviews, demonstrations, and training videos is an external microphone plugged into the Griffin iMic adapter. As good as the microphone is that's built in to the iSight, it's designed to be close to the sound source, such as when it's attached to your computer, and you're talking into it.

But when using the iSight as a video camera, it will be too far away from your subject to serve as a decent audio input device. Plug a mic directly into your Mac instead (via the iMic) and QuickTime will synchronize the audio and video for you, resulting in much clearer dialog.

Troubleshooting tip -- If your audio is out of sync with your video, make sure that iChat AV is turned off and not running. Then try using a different microphone other than the one built in to the iSight, such as an external mic or the one in your laptop. Also, check your CPU load in QuickTime Broadcaster. If you're pegged at 100 percent, bad things can happen.

Capturing Video with QuickTime Broadcaster

QuickTime Broadcaster is amazing software that you can download for free. It enables you to capture audio and video with the iSight, encode it with any QuickTime codec (including Mpeg-4), and either stream it to another computer via the Internet, or save it as a movie file to your hard drive.

Screen shot.
Figure 3. By revealing details in QuickTime Broadcaster, you can configure your audio, video, and network settings.

After you download this application, connect your iSight, turn off iChat AV, and launch Broadcaster. First thing you'll want to do is hit the "Show Details" button to reveal the settings dialog. Go to the Network tab and set it up as in Figure 3. The most important settings are "Transmission," which should be set to "Manual Unicast," and "Address," which should be set to 127.0.0.1. You can leave the audio and video post settings alone. By entering these settings, you're telling Broadcaster to save to hard disc instead of transmitting over the Internet.

Now go to the Video tab and choose your codec and enter your parameters. This is where your CPU processing power will make a big difference. The settings in Figure 4 were about as far as I could push a 667 MHz PowerBook G4. With this configuration my CPU load during recording averaged around 70 percent, enabling clean, synchronized audio and video capture. Broadcaster indicates your CPU load while recording, which makes it very easy to monitor the situation. I noticed if I pushed the limits too much, by increasing dimensions (to 640 x 480), frame rate (to 30 fps), or data rate (to the neighborhood of 2000 kbits/sec), my CPU load would begin to max out on the 667 TiBook. But the settings in Figure 4 kept things well within reasonable limits. You can push the parameter that's most important to you, such as frame size, but remember to give on others, such as frame rate.

Screen shot.
Figure 4. My ideal video settings for a 667 MHz PowerBook.

Recording direct to disc is resource intensive. This became apparent when I plugged the iSight into a 1 GHz TiBook and noticed that the CPU load dropped in half with the same numbers in Figure 4. That means I could increase frame dimensions, frame rate, or data rate without maxing out my processor. For most TiBooks and newer iBooks, the Figure 4 settings should be a good starting point. If you have a faster machine, you can push the limits accordingly.

As for the compressor itself, I had very good luck with Mpeg-4 video. You can use other compressors such as Sorenson Video or Motion Jpeg, but I didn't see any real advantages in CPU usage, and certainly not in image quality. If you plan to share your videos on the web at a later date, you might decide to use a different codec when you export. As an example, I used the new Sorenson 3 video codec for the movie sample in Figure 9. For the Figure 10 sample, however, I used the older Sorenson 1 codec because it works better on older machines with weaker processors. All of these codecs are available in QuickTime Pro, and it's a matter of finding the best one to suit your needs.

Pages: 1, 2

Next Pagearrow