Issue: Volume: 31 Issue: 8 (Aug. 2008)

Composting for the High-Definition Age


Yet again, the world is changing. 

The world of video is in the process of a major transition. The 50-year-old standard-definition TV format is slowly going away in favor of high definition. LCD and plasma televisions have dropped in price and are flying off store shelves, and customers are demanding high-resolution content to feed these large screens.

In the early part of this year, the high-definition format war between Sony and Toshiba ended when Sony’s Blu-ray prevailed, clearing the way for that format to replace the venerable DVD. High-definition broadcasts are also becoming more prevalent. Cable and satellite providers are adding more HD channels every year, and digital broadcasts will become the US standard in 2009.

This demand for HD content puts new demands on digital content creators. A stream of 1920x1080 HD video requires six times the storage and bandwidth of standard-definition (720x480) video. Compositing is one area that is particularly affected because it combines multiple streams of video into a single image, multiplying the bandwidth requirements and taxing both the hardware and software. Not only does the increased amount of data require faster and more capable computers, it also requires faster software.

The high end of the compositing world has been doing this sort of work for well over a decade. Those in feature films have always worked in high-definition formats, and, historically, compositing for features has always been at the cutting edge of technology and performance.

High on Hardware
High-end systems, such as Autodesk’s Flame, cut their teeth in the world of feature films, where large files and huge bandwidths have always been an issue. To achieve this level of performance, Flame has always required dedicated hardware that has been tuned for maximum performance. Originally, this hardware was high-end Silicon Graphics-based machinery, but these days the software runs on a much more standard Linux-based workstation. Current versions of Flame ship with an HP xw8600 workstation configured with a top-of-the-line Nvidia Quadro FX 5600 graphics card and an AJA HD video subsystem. The bottom line here is that fast hardware is the engine that runs a good compositing system. 

Of course, fast hardware isn’t limited to high-end compositing systems such as Flame; it also can power just about any compositing package. Today’s quad-core processors provide tons of horsepower, and when combined with a fast disk array, you can do very high end work with a reasonably priced system.   

Eyeon’s Digital Fusion is used for feature-film work, and as such, is ideal for handling visual effects and finishing work. It sports a node-based structure with a powerful scripting engine.
 
For those who use Apple products, the Mac Pro has always been a very capable machine. The current system sports dual quad-core processors for a total of eight processors. On the Windows side, companies such as Boxx and HP can also configure systems with dual quad-core Intel Xeon processors for similar performance. If you marry any of these with a fast RAID disk system, you have a machine that can composite multiple HD streams in real time.   

One advance that helps high-definition compositing is the advent of the 64-bit operating system. Linux and Mac OS have been 64-bit for quite some time, and Windows offers a 64-bit version of XP and Vista. The big advantage of having a 64-bit OS is increased bandwidth and the ability to address more than 4gb of RAM. Most compositing systems create their previews in RAM, so HD naturally requires more RAM. 

The bottom line is that the high-end machines are required for compositing high-end graphics. Ideally, the resolution of the monitor required for compositing HD should be higher than HD resolution so the images display at full resolution. This means a 30-inch monitor or dual 24-inch monitors are needed. To power such a large display, you need a capable graphics card, such as an Nvidia Quadro or AMD ATI FireGL card. These OpenGL cards can also provide acceleration for tasks within compositing programs, such as Adobe After Effects. 

Software Support
Of course, the hardware is only half the story; the software itself is probably the most important part of the equation. After Effects has always been the “everyman’s” compositing tool and is used by a wide array of studios to create everything from motion graphics, to character animation, to special effects. After Effects CS3, the latest version of the software, speeds up the software for HD with new multicore and graphics acceleration plus disk caching. The new version also provides a number of new tools, including the Puppet Tool for character animation. The new Brainstorm feature can speed up production by generating animation variations based on chosen parameters. 

Autodesk has a number of solutions for HD compositing. In addition to the high-end Flame, Flint, and Inferno systems, the company also has Combustion, which is a more affordable desktop version. Combustion offers a powerful 3D compositing solution on both Windows- and Macintosh-based systems. For those using HD, it provides OpenGL and multiprocessor acceleration.

Fast compositing systems require fast hardware. The Mac Pro has proved itself as a very capable machine in this area.
 
One of the key features of Combustion is its integration with other Autodesk software. It can be used to feed higher-end systems, such as Flame, and it can also be fed from 3D applications such as Autodesk’s 3ds Max and Maya.

For those situations where HD is not enough, the next new trend is not only increasing the size of the image, but also the dynamic range of the image. These high dynamic range images (HDRI) require additional data for high bit depths, as well as compositing software than can handle them. Autodesk’s Toxic 2008 specializes in HDRI compositing and is ideally suited for special effects work where a high degree of realism is required. The software integrates particularly well with Maya, which allows artists to export high-quality images directly to Toxik. 

Eyeon’s Fusion has been used in a number of feature films, and is well suited for HD compositing for special effects and finishing. Fusion uses a node-based compositing system with a powerful scripting engine to provide both ease of use and power. It also has a 3D particle system for special effects.

Fusion provides users a high degree of interactive and playback performance through the use of a powerful, multiple-tool memory cache. This cache stores processed images from active tools in memory, so they are ready for immediate playback and processing. This enables playback speeds of well over 30 frames per second and makes the most efficient possible use of RAM.

For compositing high-resolution images, the entire hardware system should be considered, including the resolution of the monitor so the graphics display at full resolution.
 
On the Apple side, Shake is a venerable tool for creating special effects, and has been used on a wide variety of feature films, including The Lord of the Rings trilogy. It was designed specifically for handling large images, so the software is more than capable for HD compositing. In addition to its role in features, Shake also works well in broadcast environments. One of the better broadcast features of Shake is its tight integration with Apple’s Final Cut Pro, allowing for the quick transfer of data between the two.

As we move into the high-definition era, we will need to handle larger images, and those images will need to be higher quality. Compositing will become an increasingly important way to add quality to images, not only with better special effects, but also with finishing tools that put the final polish on a project. The current crop of compositing software and hardware can handle these tasks to create a new level of quality for all sorts of high-definition content.

George Maestri is a contributing editor for Computer Graphics World and president/CEO of RubberBug animation studio. He can be reached at maestri@rubberbug.com.
 

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