In June 1999, digital cinema technology was used commercially for the first time when a digital cinema version of the movie "Star Wars: Episode I—The Phantom Menace" was presented in six theaters. This presentation was a landmark event in many ways, but it primarily demonstrated that digital cinema can be a viable option for movie production and playback. The commercial digital cinema experience creates new opportunities for everyone involved in the movie-making process, including filmmakers, producers, theater owners, and even moviegoers.
Abstract
This article describes the process of bringing the BMW Films Digital Cinema Series to movie theaters and the system used to project the films digitally by using Microsoft® Windows Media® 9 Series.
For nearly a century, photographic film has been used to record, edit, and present movies in theaters. With digital cinema, movies are played from files stored digitally on a hard disk or DVDs. A digital projector renders the digital stream with microchips and microscopic mirrors, and then projects the movie on a theater screen. Sound from the digital stream is converted to an analog signal and played through the theater speakers. The experience of the moviegoer is the same or better than that of viewing a film. A movie can be shot and edited on film and then digitized for distribution and playback in digital cinema theaters, or it can be produced entirely in the digital domain by using high-definition camcorders, editors, and processors. By working with digital cinema throughout the production process, filmmakers can work more efficiently with fewer creative limitations.
One problem preventing large-scale deployment of digital cinema is the very large amount of data that is needed to produce a high-resolution motion picture image on a theater screen. The bit rate of this data must also be very high for the movie to render in real time. To accommodate this need, computers with large and fast hard disks and proprietary software are used, but the cost of these systems can be prohibitive for many theaters. Digital cinema systems typically use the Motion Picture Experts Group-2 (MPEG-2) codec, which produces high-quality images but does not provide enough file compression to lower the cost of the equipment. The solution then for making digital cinema more cost-effective and therefore more viable for theater owners can be found in the codec. The less data there is to store and the lower the bit rate of the stream, the lower the cost of the system.
With the Microsoft® Windows Media® 9 Series codecs, a movie file can be compressed to one-tenth the size of a movie file compressed by using the MPEG-2 codec while maintaining the quality of the image and sound. The additional compression enables digital cinema system designers to use off-the-shelf computers and storage systems and enables producers to distribute movies for lower costs.
To show how a Windows Media-based digital cinema solution is deployed, this article describes the process used to bring the BMW Films Digital Cinema Series to theaters. This process involved creating a portable Windows Media-based digital cinema system, installing the system in 23 theaters around the United States, and converting a number of films to Windows Media files. In November 2002, the BMW Films Digital Cinema Series premiered with the short film "The Hire" from BMW Films followed by the full-length feature "Standing in the Shadows of Motown," from Artisan Entertainment.
This article covers the following topics:
Background. Describes how the BMW Film Digital Cinema Series project was developed.
Development. Details the creation of the portable digital cinema system used to play back the movies.
Installation. Describes wiring and configuring the system in 23 theaters.
Acquisition and Encoding. Describes the process of converting the movies to Windows Media files.
Presentation. Describes the process of projecting the digital media in theaters.
Conclusion. Provides details about current Windows Media-based digital cinema solutions.
For many years, filmmakers, producers, and technicians have worked within the limitations imposed by their media. Film standards, for example, impose resolution and frame rate restrictions. A producer cannot arbitrarily change the film frame size to 40 millimeters, for example, because the photographic film and the equipment to shoot, edit, and project the film would have to be created and distributed. Television standards, such as National Television System Committee (NTSC), limit the resolution and color quality of an image to standards created more than 50 years ago.
With digital media, however, these restrictions do not apply. After the frames of film or video are turned into a digital format, almost all limitations go away. For example, you can take a digitized feature film, apply compression to it, adjust the frame size and rate, change the encoder configuration to reduce the bit rate, convert the movie to Windows Media Format, and stream the feature over the Internet to users with broadband connections. Or you could compress the content more and make it available for users with dial-up connections. If you take the high-resolution digitized movie and change the compression settings to a higher bit rate, larger frame size, and standard frame rate, you can play the movie back in a theater with a digital projector. In addition, you can change the frame aspect ratio and other properties of the movie easily, without being affected by the barriers imposed by a physical medium or standards. To change the properties of your digital movie, you simply change the settings in Windows Media Encoder 9 Series and encode a new file.
The main differences between streaming a file over the Internet and playing a file back on a theater screen are the compression settings used to make the files and the requirements for the two computers used to play the files back. The theater computer must have a faster CPU, hard disk, and bus than the computer used for streaming Internet files. Despite these requirements, you can purchase an off-the-shelf computer capable of playing back files to a theater screen at a relatively low cost.
Again, the codec is the key to making digital cinema work. An uncompressed film may require several terabytes of memory. After being compressing with the MPEG-2 codec, a full-length movie requires about 40 to 50 gigabytes (GB) of storage and plays back at 80 megabits per second (Mbps). To play back content at that bit rate, the theaters need expensive computers with proprietary software. When movies are compressed by using Windows Media 9 Series codecs, high-quality content requires 4 to 6 GB of memory and can be played back at a bit rate of 6 to 8 Mbps. It is possible then to use the Windows Media codecs to compress a movie to be played back in a theater from a single DVD and using an off-the-shelf computer.
Deploying Windows Media Digital Cinema
To demonstrate the Windows Media digital cinema concept, Microsoft worked with the distributors of the independent feature film "Wendigo" in 2001 to release the movie in the Windows Media format in three theaters. This was the first commercial release of a movie in a theater that used Windows Media-based digital cinema system. The release successfully showed that the digital cinema system can provide a cost-effective, viable solution for delivering digital media to a theater screen. It also demonstrated the superb quality of the Windows Media codecs. Most moviegoers were unaware that they were watching digital media content. For information about digital cinema quality, see the paper Producing a High-Definition Windows Media File.
At the same time, the Windows Media team worked with BMW Films to encode a series of short films that were to be distributed on the Internet to broadband users. When representatives from the creative service working for BMW Films viewed "Wendigo" in the theater, they were so impressed with the quality that they decided to expand distribution of their online series to include theatrical release. BMW Films and Microsoft reached an agreement, and the BMW Films Digital Cinema Series was created.
The BMW Films Digital Cinema Series consists of eight full-length independent movies, each of which is preceded by a BMW Films short. The first film in the series played in 23 digital cinema-equipped theaters, with at least two additional theaters added for the rest the series. For more information about the series, see the BMW Films Web site and WindowsMedia.com.
Before the movies could be released to theaters, the films had to be digitized and encoded as Windows Media Video files. In addition, the team had to create the entire presentation infrastructure, including the development and installation of the hardware and software required to play back the movies in the theaters.
Microsoft had been working with Digital Cinema Solutions, Inc. (DCS) to design and build solutions for digital cinema theatrical playback. For the BMW Films Digital Cinema Series, the team realized that each theater required a Windows Media-based digital cinema playback system that fulfilled the following requirements:
Film-quality playback. The image and sound experienced by the viewer had to be at least equivalent to that of film. Projectors that display digital images have been available for a number of years. However, it was not until fairly recently that microchip technology advanced to the point where digital projectors are capable of producing images with enough resolution and brightness to compete with film.
Windows Media-based system. By being Windows Media-based, the system could make use of a wide variety of off-the-shelf software and hardware, such as computers and video cards, therefore eliminating the need for expensive proprietary solutions.
Complete solution. The system had to be a complete solution that could fit easily into a number of different projection booth configurations. Theaters, especially small independent theaters, are often unable to make large investments in new technology. Therefore, the system needed to be a self-contained, ready-to-use solution. Theaters would only have to provide a screen, a theater sound system, and electrical power.
Portability. The systems had to be portable so they could be easily moved into and removed from a projection booth.
Easy installation and configuration. In order to keep costs down and minimize impact on each theater, the installation process needed to be quick and easy and require as little configuration and disruption of existing systems as possible. When the team studied the layouts of the theaters, it became clear that achieving this goal was not going to be easy. Even though all theaters had the same basic equipment, no two theaters were configured in the same manner. This meant every theater required some type of customization. For example, the 220-volt power needed for the digital projectors was often hard-wired to the 35mm film projectors, so in some booths, outlets had to be installed.
Reliability. The system needed to be rugged and reliable. It also needed to be capable of running consistently with no failures and little or no maintenance for continuous periods of time. Most computers and hard disks are designed to transfer and process data quickly in relatively small amounts. When rendering a movie, however, the computer must transfer and process large amounts of data in real time for the length of the movie, which can be several hours. The computer needed to render data quickly and reliably over extended periods of time.
The following figure shows the final system developed by the team.
The system consists of the following components:
Cart
Projector
Computer
Patch bay
Monitors, keyboard, and mouse
Video display cards
Sound card and external module
Audio line converter
Universal Serial Bus (USB) 2.0 external hard disk drive
Cart
The system is mounted in a custom-configured mobile cart. The projector is mounted on a hydraulic shelf that enables it to be positioned vertically to accommodate a variety of projection porthole heights and configurations. Fine alignment of the image is accomplished with adjusters on the projector feet and by electronically positioning the optics. The computer and other components are mounted below the projector.
Projector
The systems include projectors from Digital Projection, Inc. (DPI). Most systems use the HIGHlite 6000Dsx digital projector; one system required higher light output and used the Thunder 10000Dsx instead. Windows Media Video files are encoded at a resolution of 1280 pixels by 720 pixels, which is the maximum horizontal resolution available for the projectors.
Most current digital cinema projectors can achieve the brightness and quality of film or a "film look" by using Digital Light Processing (DLP) technology based on the Digital Micromirror Device (DMD chip) from Texas Instruments. The DMD chip is a precise light switch that modulates light digitally with up to 1.3 million microscopic mirrors, each corresponding to one pixel. The three-chip system used in theater projection systems is capable of rendering no fewer than 35 trillion colors. New 2K chips from Texas Instruments feature twice the horizontal resolution, 1920 pixels by 1080 pixels.
Computer
The systems installed in the 23 theaters each contain a Dell computer with a single 2.8 gigahertz (GHz) Pentium 4 processor running Microsoft Windows® XP Professional. As processor speeds continue to increase, producers will be able to take advantage of the faster processors by increasing the resolution of their movies. Encoding at a higher resolution is simply a matter of changing the codec configuration in Windows Media Encoder 9 Series.
In addition to a fast processor, the computer features a fast PCI bus and a hard disk with a large amount of memory and sustained read speeds that can support an 8-Mbps stream for a few hours. Computers with these specifications are available now.
The computer system also includes a keyboard and mouse.
Patch Bay
A patch bay provides a variety of ports for connecting the cart to the theater sound system and external video sources to the projector. For example, the projectionist could patch the output of a videocassette recorder or an external computer to the projector. The digital cinema-equipped theater could then play back videotapes and could be used as a venue for live events or business meetings that include Microsoft PowerPoint® slide shows.
Video Display Cards
The computer contains a number of video display cards that provide video data to the projector and to an in-booth monitor. The projectionist can use the in-booth monitor to view the video instead of having to view it through the porthole window. The video output is also connected to a touch-screen monitor in the booth. The projectionist uses the touch-screen monitor to control playback and other functions by using the DCS Theater Manager software.
The DCS Cinema System uses Digital Video Interface (DVI) output to project images. The DVI standard was created to support both digital and analog video display monitors. DVI can handle bandwidths over 160 megahertz (MHz), so it is well-suited for delivering the 8-Mbps digital stream to the projector.
Sound Card and External Module
Up to eight tracks of sound are combined with the video into a single Windows Media Video file. When Windows Media Player renders the file, the tracks are sent to the channels of a professional-quality digital audio interface. Up to eight discrete channels are then fed into the in-theater cinema audio processor. To accommodate a variety of existing systems, DCS created custom audio wiring harnesses.
USB 2.0 External Hard Disk Drive
In the current system design, the digital media files can be distributed to theaters on an external hard disk drive that uses either the Universal Serial Bus (USB) 1.0 or 2.0 standards. Although the movies can be played back from the external drive, the files are transferred to and played back from the computer's internal hard disk in order to ensure reliable playback. The USB 2.0 standard extends performance of USB by up to 40 times. By using USB 2.0, you can transfer an entire 5 gigabyte (GB) movie from the external hard disk drive to the internal hard disk in nine minutes.
The following steps outline the process of installing the Windows Media-based digital cinema system in a projector booth:
Position the cart. The cart is rolled into place beneath an empty projector porthole, and the hydraulic shelf is raised to position the projector lens at the correct height.
Connect power. The projector is connected to a 220-volt, 1.5-kilowatt circuit. The other components are connected to a standard 110-volt outlet.
Connect components. One DVI output from the computer is connected to the projector and in-booth monitor and analog video output is connected to the touch-screen monitor. The mouse and keyboard are also connected.
Connect DSL. The system is fully networked for Internet access.
Connect audio to theater system. The DCS audio harness connects the multichannel audio interface output to the theater audio processor. If necessary, sound experts can ensure that playback sound is adjusted properly. Because the sound from the computer is digital, the theater does not need to use noise reduction systems. The output is connected to the theater processor because the processor provides the easiest access to the theater sound system. By connecting to the processor, the installers can also take advantage of the theater equalization system that tunes the sound output to the acoustic characteristics of the room.
Connect theater automation. If available, the theater automation system can be connected to the computer and controlled through the DCS Theater Manager. This enables the projectionist to perform other tasks, such as adjusting house lights and curtains, while running the film from the touch screen.
Adjust the projector image. Fine adjustments are made to the positioning of the projector so that the image aligns properly with the screen. At the same time, the zoom lens is adjusted so that the frame is correctly sized for the screen. Electronic adjustments can also be made on the projector to digitally adjust image properties.
Copy the digital media files. After the system is set up completely, the digital media files containing the short film and full-length movie are copied from the external hard disk drive to the internal hard disk. The final file for the full-length movie is about 5 GB, and the 10-minute short film requires about 600 MB. Digital cinema files can be played back directly from the external hard disk drive, DVDs, and even CDs. However, extensive testing has not been done to ensure the reliability of this method for extended use. Files can also be downloaded remotely through Digital Subscriber Line (DSL).
Play back the movie. Final adjustments to picture and sound can be made while playing the movie.
While the digital media systems were being installed, the movies were being converted from photographic film to digital Windows Media Video files.
The conversion process from film to Windows Media-based content is relatively straightforward. Film is run through a scanner, which converts light to a data stream that is then stored on a digital disk recorder (DDR) or recorded on a digital videotape. When the movie is in data form, it can be manipulated by using effects software and hardware, if necessary, and then compressed and encoded in Windows Media Format.
DuArt Film and Video in New York handled the conversion of the film and, in doing so, developed processes for optimizing digital cinema content for Windows Media 9 Series. For complete information about working with high-definition content, see the article Producing a High-Definition Windows Media Video File.
The following steps outline the mastering process used for the movies in the BMW Films Digital Cinema Series:
Acquisition. The film is run through a high-definition film scanner or telecine, which converts or digitizes the film frames to data and then stores it on a DDR in the Digital Moving-Picture Exchange (DPX) or Cineon format. If necessary, the film can be color corrected before being digitized.
Effects. If necessary, film effects software can be used to add effects or enhance the digital images.
RGB to AVI conversion. The final color-corrected file is converted to AVI format, so that Windows Media Encoder can use it as a source. Typically, a movie file is saved as a sequence of bitmap images. Various editing tools can be used to import image sequence files and export .avi files.
Audio conversion to waveform-extensible file. The films are mixed in multichannel 5.1 sound, which contains 6 channels of audio: front left, front center, front right, back left, back right, and low frequency enhance. For the encoder to be able to encode the tracks and synchronize them properly with the pictures, the audio files are combined into a single multichannel waveform file. The file is formatted in the most current version of the waveform file format, which supports multiple channels.
Encoding .avi and waveform files to Windows Media Video files. A Pentium 4 processor running Windows XP Professional is used to encode the files. Windows Media Encoder is configured to source from the .avi and waveform-extensible files and compress the video at a resolution of 1280 pixels by 720 pixels at 23.976 frames per second, with a variable bit rate of 8 Mbps. The Windows Media Video 9 codec compresses the image to 8-bit YUV with 4:2:0 sampling.
Transfer to distribution medium. The final Windows Media files are copied to the external hard disk drive or to a DVD, which is then distributed to theaters. As mentioned earlier, the theaters can also download the files remotely over a DSL connection.
Although the process for capturing and encoding content to Windows Media files has not changed in several years, changes needed to be made to the process in order to work with digital cinema content. Currently, the process of converting from Cineon-formatted files or DPX-formatted files on the DDR to a format supported by Windows Media Encoder is time-consuming. The DDR files need to be converted to the AVI format, a process which can take up to 70 hours for a full-length movie. To alleviate this problem, Microsoft is working with other companies to create a filter plug-in for the encoder that enables it to source DDR files directly.
To run the presentation, the projectionist simply starts the playlist that contains the movie flies. The Windows Media files could be played back in Windows Media Player. However, doing so would display the Player interface, including the transport controls and mouse pointer, on the screen, which would create a confusing experience for the audience. To solve the problem, DCS developed Theater Manager, a custom program that plays the movie using the full screen and provides all the features necessary for the projectionist to manage the content with a touch screen. The projectionist can use the program to create and run playlists that include all the elements of a theater experience, such as trailers, commercials, short films, and the full-length movie.
In general, the deployment of the BMW Films Digital Cinema Series was a technical success thanks to the collaborative efforts of a number of companies. This collaboration also resulted in an effective and commercially viable system for the presentation of Windows Media-based digital cinema. The best way to judge the quality of Windows Media-based digital cinema is to see and hear it for yourself. The system described in this article is installed in the following theaters.
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