QuickTime Media Layer
Volume Number: 13
Issue Number: 7
Column Tag: Multimedia
The QuickTime Media Layer
by Tim Monroe, Apple Computer, Inc.
An overview of Apple's flagship multimedia software
Imagine that you're standing in a museum, surrounded by famous works of art. On the
wall in front of you hangs a painting by Jackson Pollack. You reach out and touch the
painting, and instantly a screen slides down in front of the painting; on the screen
appears a video showing Pollack in the process of splashing paint and stabbing wildly
at the canvas. Soon it becomes clear that he's working on the very painting that hangs
in front of you.
You move to the next room. As you enter, a voice announces that this room contains the
last few remaining vases from the Ming dynasty. You go to the center of the room and
walk around the blue and white vase that sits on a pedestal. Then you pick up the vase
to examine it further: you want to see the bottom and to look inside the vase. Suddenly,
off to the right and a bit behind you, you hear a crash as a vase collides with the
marble floor. As you turn and look, a crowd of schoolchildren hurriedly moves away
from a pile of shards. Unfazed, you utter the phrase "reassemble the vase, please." The
shards swirl up into a spinning cloud that eventually settles gracefully onto its
pedestal as a complete, unbroken vase.
Then you move into a third room. Large mobiles hang from the ceiling. You click a
switch on the wall and a fan begins to spin, gently blowing the mobiles and setting them
in motion. The fan hums and the mobiles creak and clang as they move and collide with
one another. After a few minutes, the fan stops abruptly. A wall, previously blank,
now displays a live video picture of a security guard announcing that the museum will
be closing soon. You leave the museum.
This experience - this multimedia experience - seemed so real that for a few moments
you perhaps forgot that you were sitting in front of a computer. You almost felt sorry
for the schoolchildren when they accidentally smashed the vase. And you almost even
thought you could feel that hard marble floor under your feet as you moved around in
your virtual museum. What made this experience real, what made it seem as if you
were immersed in another world, was the set of Apple multimedia technologies
collectively known as the QuickTime Media Layer (QTML). In this article, I'll provide
an overview of the QTML. I'll describe the main components of the QTML and highlight
some of the key interrelations among those components.
What Is QTML?
In a nutshell, the QuickTime Media Layer is a collection of technologies developed by
Apple Computer that allow authoring and playback of multimedia content. There are
three main technologies currently included in the QTML: QuickTime, QuickDraw 3D,
and QuickTime VR. (As we'll see later, there are several other technologies that are
loosely associated with the QTML.) What distinguishes each of these technologies, and
makes them suitable for inclusion in the QTML, are these features:
• The technology is media-rich. The QTML provides, first and foremost, an
avenue for the delivery of digital media. QTML technologies pertain to the eyes
and ears. Other sensory modes, if digitized, would be prime candidates for