We ended last time talking about QuickTime, the Mac operating system’s “media layer”. What in the world is a media layer? Simply put, a media layer is a set of system-level tools to manage video, music and images. Importing and editing video from a video camera with iMovie? QuickTime is there. “Ripping” a song from a CD into iTunes? QuickTime is there. Using the “Ken Burns Effect” to make a dramatic slideshow of your photos in iPhoto? QuickTime is there. Making your own music with GarageBand? QuickTime is there. You get the point.

The QuickTime media layer contributes greatly to the unparalleled integration of the iLife digital lifestyle applications I just mentioned. With the recent release of Mac OS 10.4 “Tiger”, the QuickTime media layer now sits atop another layer that makes it even stronger. This new layer is made up of the Core Image, Core Video, and Core Audio technologies I described in last week’s article. You’ll recall that these Core technologies take advantage of the new breed of powerful, programmable GPUs (graphics processing units) to free up the system CPU and memory to, well, compute.

Here’s an example of how the new QuickTime 7 media layer uses Core technologies. Open a QuickTime video file (let’s say a movie trailer from Apple’s extensive collection of trailers on their web site). Click on the “play” button. While the trailer is playing, select “Show A/V Controls” from the Window menu. From the resulting A/V Controls window, you can adjust the video in real time, while the video is playing, with no frame skip or loss. Adjust brightness, Color, Contrast, and Tint. Change the Playback Speed from 1/2x to 3x. Change the audio volume, balance, bass and treble, while the video is playing. Video plays at 29.97 (remember that number - there’ll be a test at the end) frames per second. So, if you choose to change the Contrast of the video, QuickTime must, “on the fly”, make Contrast changes to thirty individual frames per second of video. Think of it as adjusting thirty of your digital photos every second, and you get the feel for the computing power at work.

QuickTime 7 also features an ultra-efficient new video codec (short for “compression/decompression”) called H.264. H.264 has been chosen as the industry-standard codec for 3GPP (mobile multimedia in cell phones), as well as the coming HD-DVD and Blu-ray high definition DVD formats. Why? H.264 provides the same quality as MPEG-2 (the codec used on today’s commercial DVDs) at a third to half of the data rate, and up to four times the frame size as video encoded with the MPEG-4 standard codec at the same bit rate. Simply put, this means that bigger, better-looking movies stream faster over the internet, or take up less space on your hard drive.

Some other cool features: If you have one of Apple’s iSight web chat cameras, or any other digital video camera with a FireWire connection, you can create one-click “video postcards”. Once the video is captured, you can edit it within QuickTime – no need to use iMovie, but you could. Then, from the “Share” menu, select a size to compress the movie to, and automatically export it to an email message or your .Mac online movie theater.

When viewing a QuickTime movie in full-screen mode, simply move your mouse, and a floating palette of controls appear: pause, play, fast-forward, and rewind.

QuickTime 7 is available as a free download from Apple’s website. The “Pro” version that unlocks advanced features is $29.95, and a Windows version will be available soon.

© 2005 Peter F. Zimowski