Digital Image Formats - A Practical Guide to Video and Audio Compression - page 127

straight to disk with a digital camera, while Steven Spielberg has gone on record to say he
prefers the grainy texture of traditional film. Movies such as Minority Report achieve a
good compromise by using digital effects to realize what the director envisioned while still
preserving the film grain in the finished product by reintroducing it as a digital effect. As
ever, there is clearly no right or wrong way to do this and the directors are likely to con-
tinue making movies with a mixture of technologies for some time to come. From the
point of view of a compressionist, film grain is a bad thing.

6.9.3 Image Sizes

With the work that movie special-effects companies have been doing on fully rendered 3D
animation, a third alternative of completely computer-originated material is now avail-
able. Two companies in particular represent the technological leading edge. Industrial
Light & Magic (ILM) began work in this area in the 1970s. Some of the computer graphics
work they were doing during the early 1980s was spun out to become the Pixar company.
Both have continued to push the state of the art forward ever since.
Several companies are looking at resolutions for D-cinema that go well beyond the
current 1920

1080-sized pictures we are becoming accustomed to. Barco, Sony, NHK, and
Olympus all have interesting research and development projects underway.

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6.9.4 Aliasing Artifacts

Pixar has consistently delivered computer-animated content that has a vibrant and realistic
image quality. Pixar representatives have explained at conferences how they use many tricks
and shortcuts in order to simulate some computationally intensive techniques to deliver
something that looks as if it required far more computing power than was actually used.
Movies for cinema presentation are typically created at a 2.35:1 wide-screen aspect
ratio. The resolution of an individual frame of 3D animation is rendered at 2048 862 pix-

els. The quality that Pixar produces appears to be that of a much higher resolution. This is
because for every pixel being rendered, the computation averages an image that is drawn
at a much higher resolution. This saves a lot of computation time when dealing with anti-
aliasing artifacts. Figure 6-7 shows the effects of aliasing ( jaggies) on lines, and how they
are alleviated by anti-aliasing, which is covered in the discussion on visible artifacts.

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Table 6-5 D-Cinema Display Resolutions

Name Width Height

Panasonic large-venue DLP projector 1366 1080

HDTV/D-Cinema 1920 1080

Barco D-Cine DP100 2048 1080

Sony high-performance D-Cinema projector 4096 2160

NHK Ultra-HDTV prototype 8000 4000