HK1056070A - Apparatus and method for decoding digital image and audio signals - Google Patents

Description

Apparatus and method for decoding digital image and audio signal

Background

I. Field of the invention

The invention relates to encoding digital and audio images. More particularly, the invention relates to an apparatus and method for decoding digital image and audio information in a digital cinema system. The invention further relates to encoding, compressing, storing, decrypting, decompressing, decrypting and controlling playback of electronic audio/video programs from a central facility to a plurality of display projectors or display systems.

Description of the related Art

For decades, the film industry relied on the copying, distribution, and projection of celluloid film to deliver original program material to different theaters nationwide and worldwide. To a large extent, the method and mechanism of distribution of movie material remains relatively unchanged.

The process of film duplication and distribution is now illustrated in fig. 1. Film reproduction typically begins with a quality photographic negative. At the film studio 50, a film editor 52 generates a master film print after the process of generating the original film has taken place. From this main film print, the film reproduction element 54 produces what is referred to as a release film from which release versions (referred to as "prints") are mass produced. There may be more intermediate steps or multiple copies made at each stage, depending on the size of the release or desired number of copies of the movie release. As exemplified by theater 56, film prints are distributed to different theaters by courier and other physical means. At the theater 56, the film is played by reflecting the image from the film onto the display screen surface with a film projector 58. In this conventional system, multi-track audio programs are typically generated by the audio editing system 51 and printed on film along with the movie images so that the soundtracks can be played in a cinema projection system on the cinema sound system 57 in synchronization with the movie.

Although the distribution process shown in fig. 1 may work well, there are inherent limitations. Due to the use of movie celluloid material and the bandwidth limitations of the movie media, there are limitations on the ability to provide high fidelity multi-channel audio programs. Thus, there is a high cost in making a large number of movie copies, which costs several hundred dollars per feature length of the movie. There is also expense, complexity and delay associated with physically distributing large reels of celluloid film to large and growing theatre venues. Also, a growing trend in the movie theatre industry is the development of so-called "multiplex" theatre locations, where a plurality of auditoriums are located together or at a single theatre location. Each auditorium in the multi-association may show a movie at the same time as other auditoriums show the movie.

Because of the large number of copies made, it is becoming increasingly difficult to deter illegal copying and theft of material. The movie industry is estimated to lose billions of dollars in revenue each year from piracy and theft. In addition, the reproduced film material may degrade over time due to dust accumulation, wear, thermal variations, and other known factors. Finally, overhead and other costs are also included in the progressive destruction of film material, which may contain material that controls risks.

Emerging technologies are making it possible to provide alternative approaches to the present movie distribution problem. For example, satellite transmission methods are now available, although they are now not commercially viable for the distribution of high quality audio/video (AV) material. Since the distribution of movie programs is essentially a special type of broadcasting for continents, a satellite distribution method having inherent advantages seems to be basically appropriate for movie distribution for such wide-area broadcasting. However, in order to transmit good quality AV signals in real time, the required data rate (in bits per second) is on the order of 15 megabits per second. This high data rate requires capacity equivalent to an entire satellite to transmit a single program, which is very expensive. In addition, the alternative release techniques do not provide the image quality and projection brightness achieved with celluloid film. Competing technologies typically involve recording audio/video (AV) signals in different magnetic or optical media for display on a video monitor, television, or projection device. These techniques do not provide the quality of the film due to bandwidth limitations.

In addition to the ability to transmit the necessary information via satellite, the received information must be displayed by a high quality projector, which has not previously been available. Furthermore, satellite-based transmission and receiver systems are expensive and are a fundamental change from existing movie distribution and display methods. It may be perceived that such a fundamental change may not be commercially acceptable from the outset.

Advances in digital technology have also created a revolutionary distribution philosophy whereby program material is stored electronically in digitized form, rather than in optical film media. The digitized images may be distributed to different magnetic media, or compact discs, or transmitted via wired, fiber optic, wireless, or satellite communication systems. There are a variety of DVD-ROM storage formats with storage capacities ranging from about 4.5GB to about 18 GB. DVD-ROM storage formats with storage capacities greater than about 9GB are implemented on dual-sided disks. Strictly speaking, a high storage capacity DVD-ROM disk must be manually flipped to access the stored information from the second side of the disk.

An average image compression bit rate with image tracks of about 40Mbps audio and control information about eight Mbps-an average two hour movie requires approximately 45GB of storage space. Thus, even if a high storage capacity DVD-ROM disk is realized, a two-hour movie requires the use of a plurality of DVD-ROM disks for sufficient capacity.

Further to playback, an average two hour DVD-ROM movie requires information to be output at about 6 megabytes per second or about 48 Mbps. Although some existing DVD-ROM devices claim a transmission rate of 8MB per second, the quality and reliability of such devices is unknown. Thus, there is no guarantee that such a DVD-ROM device can reliably maintain a transmission rate of 6MB per second.

To reduce the data rate requirements for high quality electronic image storage, compression algorithms have been developed. A digital motion picture compression technique that provides significant compression while maintaining image signal quality uses adaptively sized blocks and sub-blocks of encoded Discrete Cosine Transform (DCT) coefficient data. This technique is referred to below as the Adaptive Block Size Discrete Cosine Transform (ABSDCT) method. The adaptive block size is selected to take advantage of redundancy that exists due to information within a frame of image data. This technique is disclosed in U.S. patent No. 5021891 entitled adaptive block size image compression method and system, which is assigned to the assignee of the present invention and is hereby incorporated by reference. DCT techniques are also described in U.S. patent No. 5107345 entitled adaptive block size image compression method and system, assigned to the assignee of the present invention and incorporated herein by reference. Furthermore, the combined use of the ABSDCT technique and the differential quadtree transform technique is discussed in U.S. patent No. 5452104 entitled "adaptive block size image compression method and system," which is also assigned to the assignee of the present invention and which is hereby incorporated by reference. The systems disclosed in these patents use intra-frame coding, where each frame of the image sequence is encoded without any care for the content of any other frame.

The distribution of film information using digital electronic forms does increase the potential for fast, low-cost reproduction without quality degradation. However, together with the "effortless copying" corresponding to digital technology, there are also encryption techniques that ensure that information is encoded in a way that prevents useful information from being transmitted to unauthorized parties.

Technologies such as ABSDCT compression technology, advanced projection devices and electronic encryption methods offer the possibility of "digital cinema" systems. In general, digital cinema refers to the electronic distribution and display of high-quality cinema programs that have been converted to digital electronic representations for the purposes of storage, transmission, and presentation. Digital cinema systems overcome many of the limitations of existing movie distribution processes. The digital system does not suffer from the outdated quality degradation experienced by celluloid film. Further, the digital system substantially eliminates theft and illicit copying of celluloid film and further provides the possibility of implementing security measures within the digital system itself. However, the film industry and related fields have not yet developed a complete digital cinema system.

Several points and problems are to be solved. New digital cinema systems require an improved form of protection to deter cinema theft. Theatre complexes with multiple auditoriums have become larger in an effort to provide greater economic returns, resulting in more complex play schedules and more places to show a particular movie. This may require many additional electronic copies to be submitted to the theatre for playback with the prior art at a corresponding complexity and operating cost.

The release channel and mechanism are still determined by the old celluloid film replication and release techniques discussed above. New technologies are needed to leverage the proposed digital cinema process to reduce copying, provide faster release to the market, and update products in release while providing increased scheduling and release flexibility at an acceptable cost. Also, some movie producers, studios and theater managers want to increase the centralized control of distribution and can expand the newer markets. For example, it would be desirable to provide movies and other audio-video presentations with selectable channels to address the growing audience market in multiple or alternative languages in a more cost effective manner.

What is needed is a technology and apparatus and method for the integration of encoding, encryption, storage, and management of digital images and audio programs. These objects are achieved by the present invention in the following manner.

Summary of The Invention

The invention is an apparatus and method in which an encoded signal representing an image in compressed and encrypted form on a storage medium and transmitted thereto is processed to initiate display of the image, the apparatus comprising a storage device configured to receive the storage medium; and a decoder configured to receive the compressed encrypted encoded signal from the storage medium. The decoder further includes a decryptor configured to decrypt the compressed encrypted encoded signal and a decompressor configured to receive the compressed encoded signal and the decompressed compressed encoded signal from the decryptor to enable display of the image, the decompressor using an inverse adaptive block size discrete cosine transform compression technique. The method of the present invention is a method of processing an encoded signal representing an image in compressed and encrypted form on a storage medium and transmitted thereto to initiate display of the image, the method comprising the steps of retrieving a compressed encrypted encoded signal from the storage medium, decrypting the compressed encrypted encoded signal to produce a compressed encoded signal, and decompressing the compressed encoded signal to initiate display of the image, the decompressing using an inverse adaptive block size discrete cosine transform compression technique.

Thus, the apparatus and method provide for decoding, decrypting and decompressing of image and/or audio information, typically in the form of program material. At the central facility or hub, the program material is digitally compressed, encrypted and stored in preparation for distribution to one or more auditoriums or theatre locations for large screen presentation of the program. The program material typically contains movie images, time-synchronized audio programs, and/or other relevant information such as video hint tracks for the low-vision audience, subtitles for foreign language and/or low-listening audiences, advertisements, or multimedia time hint channels. The program material may be long time (e.g., movie of event-length), short time (e.g., movie trailer or commercial), or still image (e.g., for advertising and promotion). Audio and other related programs need not be time synchronized with or stored with image information, such as in the case of background audio programs and advertisements.

At the central hub, program information is processed for distribution. Electronic audio and image signals from analog or digital inputs may be generated using a source generator located at a central hub or alternative location. The source generator may comprise a telecine producing an electronic image signal and an audio reader producing an electronic audio signal. Alternatively, the electronic signal may be provided directly from an electronic camera or other electron source, such as a computer-based image generation system.

The electronic image and audio signal are then processed by a compressor/encryptor. Further, the compressor/encryptor may be located in a central hub or in the same facility as the source generator, such as a production studio. The image and audio information may be stored on the storage medium using known dynamic compression techniques. Compression techniques such as the ABSDCT method described in 5452104, 5107345, and 5021891 may be used. The storage medium may be any kind of high capacity electronic tape, magnetic or optical storage device, such as a CD, DVD or hard disk, or network attached storage. Additionally, some information may instead be transmitted over wired, fiber optic, wireless, or satellite communication systems. The audio signal may be compressed and stored on a similar device using the above method or standard digital audio compression algorithms.

Encryption techniques include the use of time-varying electronic key values and/or sequences of digital control words that are provided to authorized receivers and projectors. In addition, digital signatures and "watermarks" may be added to the image and/or audio signals. The watermark is not perceptible to the average viewer but may be used to identify the source of unauthorized copies of the program when analyzed in non-real-time or still-frame playback. Decryption information necessary to decrypt the image and/or audio information is generated at a separate decryptor unit that uses the secret algorithm-specific key and the security information sent to the theater. Typically the image and audio signals are separately encrypted. By treating the image and audio portions as separate programs, different audio programs can be combined with the image program for various reasons, such as different languages.

The compressed and encrypted signals are also stored on a storage medium or provided for transmission from a central hub. If transmitted, the modulation/transmission technique may add forward error correction information and modulate the data stream for transmission. The transmission may be over any wired or wireless communication such as land cable, fiber optic cable, satellite, the internet or other methods.

The central hub further comprises network management. Network management may include a control processor to manage overall operation in both the encoder and theatre subsystems, including stored control, playback/display, security and overall monitoring/control and network management functions. Network management can work under centralized or distributed fully automatic control, semi-automatic control, or human intervention.

Under the control of network management, program material and additional control information are stored and transmitted to the theatre subsystem. Network management also includes control methods that inform the theatre subsystem of the identity of the transmitted program. Further, a control method is provided for controlling the selective storage of each cinema subsystem of the received program.

At the theatre subsystem, the storage device receives storage media from a hub. The playback module reads information from the storage medium, monitors the stored information for errors and requests retransmission of any portion of the information that contains errors. The theatre subsystem, such as theatre management, uses a communication path (from the theatre subsystem to the central hub) to request retransmission. The communication path may use a telephone network, a satellite channel, the internet, or any other communication method.

A storage device in the theatre subsystem may provide for local centralized storage of program material under the control of theatre management. The storage device may comprise a storage medium such as a DVD disc, a removable hard disk or a just a bunch of disks (JBOD) module. The storage device may store several programs at one time. The storage device may be connected via a Local Area Network (LAN) (electronic or optical) in such a way that: any program can be played and presented on any authorized projector. The same program may also be played on two or more projectors simultaneously. The program material is transmitted from the storage device to a designated auditorium via a Local Area Network (LAN) using a different LAN architecture. For the purposes of this description, it is assumed that a LAN is used in conjunction with a central network switching fabric. However, other kinds of LAN structures are possible for this subsystem.

After the playing module sequences the program data, the decoder decompresses and decrypts or decodes the program data. The decompression and decryption algorithms are based on the compression and encryption techniques used at the central hub. The decompressed/decrypted information is displayed with a projector in the auditorium and the audio signal is rendered with the electronic sound subsystem.

Theatre management generally controls all aspects of projection operations, including the storage of received programs, the decompression and decryption of program signals, and the display of program material. The theater management may also control the time and/or amount each program is allowed to play. Alternatively, control of the display process may be located at a local projector, remote control unit, or under control of a central hub or other centralized component. Further, theater management may be configured to integrate projection operations with other theater operations, such as ticketing, promotions, signage, environmental controls, lighting, sound system operations, and the like. Each theatre subsystem may also include multiple auditorium modules that share the same storage and control functions for flexible and cost-effective presentation options.

The use of digital encryption provides a fixed measure of security. Cryptographic techniques are used to provide end-to-end encrypted data transmission. That is, the image and/or audio information is encrypted at the source generator and decrypted during playback at the theatre subsystem. In addition to electronic security measures, physical security measures may provide additional protection of program material.

Physical security measures are used to protect the decompressed/decrypted signal from "piracy" prior to presentation by the theatre subsystem projector. In one embodiment, the decryption/decompression functionality is placed in a secure, self-contained chassis that is physically placed in or within the projector in the following manner: typically no authorized access is not mobile and this way physically prevents the seeking of the decrypted signal. In addition, intrusion into a secure environment or chassis may cause deletion or erasure of cryptographic key information and otherwise deletion or alteration of digital data provided at any projector port to prevent copying.

Thus, the apparatus and method are provided for decoding, decompressing and decrypting digital and audio information, as well as for monitoring and controlling the management functions of such apparatus.

Brief Description of Drawings

The features, objects, and advantages of the invention will become apparent from the detailed description set forth below when taken in conjunction with the drawings in which corresponding identified features are consistently incorporated, wherein:

fig. 1 is a block diagram of a conventional movie distribution system;

FIG. 2 is a high level block diagram of an embodiment of the digital cinema apparatus of the present invention;

FIG. 3 is a block diagram of a film-based source generator;

FIG. 4 is a block diagram of a compressor/encryptor;

FIG. 5 is a block diagram of network management;

FIG. 6 is a block diagram illustrating hub internal network and central hub redundancy;

FIGS. 7A-E are block diagrams of a storage device;

FIG. 8 is a block diagram of a storage device using multiple sequential disk players and playback players;

FIG. 9 is a block diagram of a storage device using multiple parallel disk players and playback players;

FIG. 10 is a block diagram of a storage device using a disk cartridge and a playback player;

FIG. 11 is a block diagram of a theatre subsystem that uses a removable hard disk as a storage device;

FIG. 12 is a block diagram of theater management; and

FIG. 13 is a block diagram of a theatre subsystem that uses a JBOD module as a storage device.

Detailed description of the preferred embodiments

The invention comprises apparatus and methods, sometimes referred to herein as "digital cinema", for electronic decoding, decompression and decryption of audio/video, such as movies in cinema systems, theaters, cinema complexes and/or presentation systems.

Digital cinema combines innovations in image and audio compression, projection technology, encryption methods, and many other fields. Digital cinema was designed to replace the method of today's physical release of celluloid film to every broadcast and projection venue such as a theater or a remote auditorium. Digital cinema frees the need for celluloid film replication and offers the potential for ad hoc audio/video quality and fixed security measures. The program may be transferred to the theater and stored on a storage device, such as a Removable Hard Disk (RHD) or Digital Versatile Disk (DVD), for later presentation.

The exemplary theatre or theatre complex is for clarity of the following discussion when the invention is applied equally to the presentation of image and audio information to different exhibition venues such as outdoor sports arenas, drive up theatre complexes, city auditoriums, schools, specialty restaurants, etc. Those skilled in the art will readily understand how the present invention may be applied to other types of locations.

Fig. 2 illustrates the digital cinema apparatus 100 of the present invention. The digital cinema facility 100 comprises two main systems: at least one central facility or hub 102 and at least one show or theater subsystem 104. Hub 102 and theatre subsystem 104 are similar in design to pending U.S. patent application serial No. 09/075152, filed 5/8 of 1998, which is assigned to the same assignee as the present invention and is hereby incorporated by reference.

In one embodiment, the image and audio data is compressed and stored on a storage medium and distributed from the hub 102 to the theatre subsystem 104, typically one theatre subsystem for each theatre or presentation site in a network of presentation sites that accept image and audio information, and the system includes a number of central devices, and also specific devices used by each presentation auditorium.

In the central hub 102, a source generator 108 receives film material and generates a digital version of the film. The digital information is compressed and encrypted at compressor/encryptor (CE)112 and stored on the storage medium via hub storage device 116. Network management 120 monitors and sends control information to source generator 108, CE112, and hub storage device 116. Conditional access management 124 provides special electronic key information so that only a particular theater is authorized to show a particular program.

In the theatre subsystem 104, theatre management 128 controls theatre management 132. The theater storage device 136 transmits the compressed information stored on the storage medium to the playback module 140 according to the control information received from the theater management 132. The playback module 140 receives the compressed information from the cinema storage device 126 and prepares to assign the compressed information to a predetermined sequence, size, and data rate. The playback module 140 outputs the compressed information to the decoder 144. The decoder 144 inputs compressed information from the playback module 140, decrypts, decompresses, and formats, and outputs information to the projector 148 and the sound module 152. The projector 148 plays information on the projector and the sound module 152 plays sound information on the sound system, both under the control of the theatre management 132.

In operation, the source generator 108 provides digital electronic images and/or programming to the system. In general, the source generator 108 receives film material and generates a tape containing digital information or data. The film is digitally scanned at a high resolution to produce a digitized version of the film or other program. Typically, the "telecine" process produces image information when a well-known digital audio conversion process produces the audio portion of a program. The image being processed need not be provided from a film, but may be a single picture or a still frame type image, or a series of frames or pictures, including those shown as a movie of varying length. These images may be presented as a series or group to produce what is referred to as an image program. In addition, other material such as a video alert channel for a poor-sighted viewer, a subtitle or multimedia time alert channel for a foreign language and/or poor-listening viewer may also be provided. Similarly, individual or groups of sounds or recordings are used to form the desired audio program.

Alternatively, a high definition digital camera or other known digital image generating device or method may provide the digital image information. The use of a digital camera that directly produces digital image information is particularly useful for capture with a sufficiently fast or simultaneously published live event. A computer workstation or similar device can also be used to directly generate the graphic images to be distributed.

The digital image information or program is fed to a compressor/encryptor 112 which compresses the digital signal using a preselected known form and process, reducing the amount of digital information necessary to recreate the original image at a high quality. In a preferred embodiment, the image source is compressed using ABSDCT technology. ABSDCT compression techniques are proposed in the above-mentioned U.S. patent nos. 5021891, 5107345, and 5452104. The audio information may also be digitally compressed using standard techniques and may be time-synchronized with the compressed image information. The compressed image and audio information is then encrypted and/or encoded using one or more secure electronic methods.

Network management 120 monitors the status of compressor/encrypter 112 and directs compressed information from compressor/encrypter 112 to hub storage device 116. The hub memory device 116 is comprised of one or more storage media (shown in FIG. 8). The storage medium may be any kind of high capacity data storage device such as a Digital Versatile Disk (DVD) or a Removable Hard Disk (RHD) and further as described herein. Once the compressed information is stored on the storage medium, the storage medium is physically transferred to the theatre subsystem 104 and, in particular, to the theatre storage device 136.

In an alternative embodiment, the compressed image and audio information are stored independently of each other and not adjacent to or separate from each other. That is, an apparatus for compressing and storing an audio program corresponding to image information or a program but temporally isolated therefrom is provided. This need is not present when the invention is used to process audio images simultaneously. A predetermined identifier or identification mechanism or scheme is used to combine the corresponding audio and image programs with each other as appropriate. This allows the connection of one or more pre-selected audio programs to at least one pre-selected image program at the time of or during the show when required. That is, even when not initially synchronized with the compressed image information, the compressed audio is connected and synchronized at the time of the show presentation.

Further, keeping the audio program and the image program separate allows for multiple languages from the audio program to the image program without resetting the image program for each language. In addition, maintaining separate audio programs allows for support of a multi-speaker configuration without the need to interleave multiple audio tracks with the image program.

In addition to image and audio programs, separate promotional or promotional programs may be added to the system. Typically, the promotional material changes at a greater frequency than the feature program. The use of separate promotional programs allows the promotional material to be updated without the need for new feature image programs. Promotional programs contain information such as advertisements (slides, audio, puppet or the like) and trailers shown in theaters. Due to the high storage capacity of storage media such as DVD or RHD, thousands of pieces or strips of advertisements may be stored. High storage allows for specialization as if a particular slide, advertisement or trailer could be shown at a particular theater for a targeted customer.

Although fig. 2 illustrates the compression of information in storage device 116 and the physical transfer of the storage medium to theatre subsystem 104, it should also be understood that the compression or portions thereof can be transferred to theatre storage device 136 by any wireless or wired transmission method. Transmission methods include satellite transmission, well known as multipoint transmission, internet access nodes, dedicated telephone lines or point-to-point fiber optic networks.

Embodiments of the processing blocks of the central hub 102 are illustrated in fig. 2-9 and described herein. The source generator 108 is illustrated in fig. 3. In fig. 3, the source generator 108 digitizes a source 156 of motion picture images, such as 35 mm motion picture film, and stores the digital form on tape. Source generator 108 includes a High Definition (HD) "telecine" apparatus or process 164 that receives film source 156 and generates digital images from film source 156. Telecine is well known in the motion picture industry and any of several commercially available services or devices may be used to perform this process. However, in the preferred embodiment, high resolution telecine processes are used so that equipment produced by CINTEL or Philips BTS is recently available, as known to those skilled in the art. The particular choice of equipment and use when designing a service is determined based on cost and well-known factors. Alternative resolutions may also be used depending on the target audience, available projection equipment, and location, including the need to reduce the data rate for satellite transmission.

If the original movie 156 is a standard form of 35 mm source, then this process is performed on the image using a 24 frames per second telecine process. The digital output of the telecine process may be stored with a high data rate tape recorder or immediately compressed and/or encrypted and stored with a low data rate tape recorder or other known image storage systems and media.

Since a telecine only processes images, the audio portion of the output source is processed separately from the images. If the audio source is in analog form, it is typically provided on tape 168 to an audio reader for digitization. In one embodiment, up to twelve tracks of digital audio are combined with the digital image through multiplexer 176. The multiplexed signal is stored with the image program on a storage medium such as a high density digital video tape recorder 180 or on a similar high capacity digital storage system. As described above, the audio program may alternatively be stored and processed separately from the image program, but including time synchronization information to properly account for the time at which the projection auditorium presentation system is engaged in conjunction with the image program. The time synchronization information may be stored on the image program, the audio program, or a separate control program.

Although shown as part of the central hub, it should be understood that the source generator 108 may be located on a different device than the central hub 102. Other devices are suitable for generating digital signals from magnetic tape, magnetic or light sources. Alternatively, the source generator 108 may comprise a digital camera mounted magnetic or optical storage device or other image-generating digital means (e.g., for use as a computer-generated image or special effects) that directly produces digital source material. The source generator 108 may also contain a digital system of still images, such as an optical scanner or image converter for 35 mm film or photographs. Thus, for example, a typical or specialized studio for special effects or other equipment involved in the preparation and display of image programs, may generate the desired digital material, which may then be transmitted to the hub 102 for further processing or transmission.

A block diagram of the compressor/encryptor 112 is illustrated in fig. 4. Similar to the source generator 108, the compressor/encrypter system 112 may be part of the central hub 102 or located in a separate device. For example, compressor/encryptor 112 may be located in a film or television production studio with source generator 108. Additionally, the compression process for image or audio information or data may be performed in a variable rate process.

Compressor/encryptor 112 receives the numbers provided by source generator 108. The digital image and audio information is stored in a frame buffer (not shown) before further processing.

The digital image signal is passed to an image compressor 184. In a preferred embodiment, the image compressor 184 processes the digital image signals using the ABSDCT technique described in the above-mentioned U.S. patent nos. 5021891, 5107345, and 5452104.

In the ABSDCT technique, the color input signal is typically in YIQ mode, where Y is the luminance or brightness component and I and Q are the chrominance or color components. Other formats such as YUV or RGB formats may also be utilized. The ABSDCT technique subsamples the color (I and Q) components by a factor of two per direction in both the lateral and longitudinal directions due to the eye's low spatial sensitivity to color. Thus, each spatial segment of the image input is represented by four luminance components and two chrominance components.

Each luminance and chrominance component is passed to a block interleaver. Typically a 16 x 16 (pixel) block is fed to a block interleaver which orders or organizes the image samples within each 16 x 16 block to produce blocks of data and composite sub-blocks for Discrete Cosine Transform (DCT) analysis. The DCT operator is a method of converting a time-sampled signal to a frequency representation of the same signal. By converting to a frequency representation, display DCT techniques can involve a very high level of compression, as the quantizer can be designed to take advantage of the frequency distribution characteristics of the image. In a preferred embodiment, one 16 × 16 DCT is used for the first order, four 8 × 8 DCTs are used for the second order, 164 × 4 DCTs are used for the third order, and 64 2 × 2 DCTs are used for the fourth order.

The operation of the DCT reduces the spatial redundancy inherent in the video source. After DCT, most of the video signal energy tends to concentrate in a few DC coefficients.

For a 16 x 16 block and each sub-block, the transformed coefficients are analyzed to determine the number of bits required to encode the block or sub-block. The block or combination of sub-blocks that requires the least number of bits to encode is then selected to represent the image segment. For example, two 8 × 8 sub-blocks, six 4 × 4 sub-blocks and eight 2 × 2 blocks may be selected to represent an image segment.

The selected blocks or combinations of sub-blocks are then suitably ordered. The DCT coefficient values may then be subjected to further processing in preparation for transmission such as, but not limited to, frequency weighting, quantization, and encoding using known techniques (e.g., variable length coding). The compressed image signal is then provided to at least one image encryptor 188.

The digital audio signal is typically passed to an audio compressor 192. In the preferred embodiment, audio compressor 192 processes multiple audio information using standard digital audio compression algorithms. The compressed audio signals are provided to at least one audio encryptor 196. Alternatively, the audio information may be delivered and used in an uncompressed but still digital mode.

The image encryptor 192 and the audio encryptor 196 encrypt the compressed image and audio signals, respectively, using any known encryption technique. The image and audio signals may be encrypted using the same or different techniques. In a preferred embodiment, encryption techniques are used that involve the encoding of real-time digital sequences of images and audio programs.

At the image and audio encryptors 192 and 196, the program material is processed by scrambler/encryptor circuits using time-varying electronic key information (typically varying several times per second). The encoded program information is then stored or transmitted, such as over-the-air wireless connection, so as to be uninterpretable to anyone who does not hold the associated electronic key for the encoded program material or digital data.

Encryption typically includes digital sequence encoding or direct encryption of compressed signals. The words "encryption" and "encoding" are used interchangeably and may be understood to mean any means of encoding, overwriting or directly encrypting a digital data string of different sources using the sequence of digital strings generated from a secret digital value ("key") using any cryptographic technique, such that it is difficult to recover the original data sequence without the secret key value.

Each image or audio program may use specific electronic key information provided and encrypted for the theater or the show venue authorized to show the specific program by the show venue or theater specific electronic key information. The conditional access management 124 or CAM handles this function. The encrypted program key required by the auditorium to decrypt the stored information is transmitted or otherwise delivered to the authorized theater prior to the program being broadcast. It is worth noting that the stored program information is potentially transmitted several days or weeks before the start of the authorized show time, as well as the encrypted image or audio program key is transmitted or transmitted just before the start of the authorized show time. The encrypted program key may also be transmitted using a low data rate link or a portable storage element such as a magnetic or optical media disk, smart card, or other device having an erasable memory element. The encrypted program key may also be provided in such a manner as to control the time at which a particular theater complex or auditorium is authorized to show the program.

Each theatre subsystem 104 receiving the encrypted program key decrypts the value using its auditorium-specific key and stores the decrypted program key in a storage device or other secure memory.

When the program is to be played, the cinema or venue specific and program specific key information is used, preferably with an equalization algorithm used in the decryptor 112 in preparing the encrypted signal, to now decode/decrypt the program information in real time.

Referring back to FIG. 4, in addition to encoding, image encryptor 192 may add a "watermark" to the image program, which is typically digital in nature. This includes location-specific and/or time-specific visual identifiers inserted in the program sequence. That is, watermarks are constructed to represent authorized screening locations and times, if necessary, in order to more effectively track the source of illicit copies. The watermark may also be programmed to appear at frequent but pseudo-random times during playback and to be invisible to the viewer. Watermarks are perceptually unnoticeable during presentation of decompressed image or audio information at transmission rates that are preset to be normal. However, watermarks are perceptible when the image and audio information is displayed at a different rate than normal, such as at a slower "non-real time" or still frame playback rate. If an unauthorized copy of the program is found, the digital watermark information is read by an authorized agency and the theater in which the copy was made can be determined. Such watermarking techniques may also be applied to or used to identify audio programs.

The compressed or encrypted image and audio signals are both fed to the multiplexer 200. The image and audio information is multiplexed with the time synchronization information at the multiplexer 200 to allow the image and audio string information to be played in a time aligned fashion at the theatre subsystem 104. The multiplexed signal is then processed by a program packetizer which forms program strings from the packetized data. By grouping the data or forming "data blocks," the program string can be monitored during decompression by the theatre subsystem 104 (fig. 2) for errors in receiving the blocks during decompression. A request may be made by the theatre management 128 of the theatre subsystem 104 for an error in the display of the data block. Thus, if an error exists, only a small portion of the program needs to be replaced, rather than the entire program. Requests for small blocks of data may be processed over a wired or wireless link. This provides for enhanced reliability and efficiency.

In an alternative embodiment of the invention, the image and audio portions of the program are treated as separate distinct programs. Thus, instead of multiplexing the image and audio signals using a multiplexer, the image signals are separately grouped. In this embodiment, the audio program may be removed from transmitting the image program and vice versa. Strictly speaking, the image and audio programs are only grouped into a merged program at the playing time. This allows for different audio programs to be combined with the image program for different reasons, such as different languages, providing post-publication updates or program changes to fit within local social standards, and so forth. This ability to flexibly distribute audio diverse multi-channel programming to image programming is useful to reduce costs in changing programming in a larger multi-cultural market that has been released and is now being used in the motion picture industry.

The compressors 184 and 192, encryptors 188 and 196, multiplexer 200 and program packetizer 204 may be implemented by a compression/encryption module (CEM) controller 208, which is a software-controlled processor configured to implement the functions described herein. That is, they are configured as uniformly functioning hardware, including different programmable electronic devices or calculators operating under software or firmware program control. They may alternatively be implemented using some other technique, such as through an ASIC or through one or more circuit card integrations. That is, constructed as specialized hardware.

The image and audio program strings are sent to the hub storage device 116. The CEM controller 208 is primarily responsible for controlling and monitoring the entire compressor/encryptor 112. The CEM controller 208 may be implemented by setting general-purpose hardware devices or calculators to perform the required functions or by using specialized hardware. Network control is provided to the CEM controller 208 from the network manager 120 (fig. 2) over the hub internal network, as described herein. CEM controller 208 communicates with and controls the operation of compressors 184 and 192, encryptors 188 and 196, multiplexer 200 and packetizer 204 using a known digital interface, and may also control and monitor memory module 116 and the transfer of data between these devices.

The storage device 116 is preferably constructed as one or more RHDs, DVD discs or other high capacity storage media, which are generally of similar design to the theatre storage device 116 of the theatre subsystem 104 (fig. 2). However, one of ordinary skill in the art will recognize that other mediums may be used in some applications. The storage device 116 receives compressed and encrypted images, audio, and control data from the program packetizer 204 during a compression stage. The operation of the storage device 116 is managed by the CEM controller 208.

Referring now to fig. 5, network management 120 is illustrated. Network management 120 controls and manages hub 102, optionally controlling and managing the control and monitoring of the entire digital cinema system 100, including one or more of the components of cinema system 104. Centralized control enables network management 120 to manage the overall operation of the system, including transport, play/display, security control, and overall network management functions. Alternatively, a distributed management system may be implemented in which processors in the presentation and theatre systems control some of the theatre functions.

The network manager 120 includes at least one network management processor 212, which is the central controller or "brain" of the digital cinema system 100. The general network management 120 is based on a standard platform workstation or similar programmable data processing hardware. The network management processor 212 manages the scheduling and security aspects of the hub 102. Under network management control, updates to the control information or program are transmitted from the hub 102 to the theatre subsystem 104 prior to the show time. The network management processor 212 also controls the transmission rate of the programming transmitted or otherwise communicated to the theatre subsystem 104. The transmission rate may be fixed or variable depending on the type of program and the design of the transmission channel or path. This may be based on, for example, the transmission rate for a particular data link. The data rate at which the program material is compression encoded may also be varied for different programs to provide different quality levels of compression.

The network management processor 212 interfaces with the rest of the hub through a hub intranet, which is typically implemented using standard multipoint network architectures. However, other known network designs and classes may be used including optical-based links. In a preferred embodiment, Ethernet hub 216 of network management system 112 supports an intra-hub network, as discussed herein with reference to FIG. 6.

Network management 120 may also include a modem 220 that provides an interface to a cinema network over the internet or PSTN, and typically includes a set of dial-up telephone modems, cable or satellite modems, ISDN or cellular link controllers, or other known devices. The modem 220 interfaces with the network management processor 212 through a modem server function. The modem 220 serves as a receiver for the return link communication path from the theater to the central hub 102. For example, the theatre management 128 illustrated in fig. 7 monitors the quality of the compression process of the theatre subsystem 104 and provides a quality report to the network management system 120. The return path may be used by the theater requesting retransmission of the corrupted program data block from the central hub 102. In addition, additional showings of the program or changes or updates to the program material may be requested via this link. In alternative embodiments, the return path may be provided through a satellite channel or another low data rate communication method, or through the internet. In this case, other known docking means or devices are implemented instead of the modem 220 as appropriate.

The user interface 224 allows the user to directly control the network management 112 and thus the entire hub 102 and/or theatre subsystem 104. The user can monitor the status of the hub 102 and indicate the timing of the various modules of the hub. Further, the user interface 224 allows for the configuration of different embodiments of the storage device 116, including the type of storage medium used and how and where programs are stored on the storage medium. The user interface 224 is typically a personal computer with a monitor and keyboard interface.

Referring now to FIG. 6, a block diagram of the hub internal network 228 is illustrated. The hub internal network 228 is the communication backbone of the central hub 102. Hub internal network 228 may be internally extended to an ethernet Local Area Network (LAN) running the IP protocol suite. In this way, the hub internal network 228 physically interconnects the compressor/encrypter 112, the storage device 116, the network management 120, the conditional access management 124, and optionally the theatre management 128 of the theatre subsystem 104 to the ethernet hub 232. The hub internal network 228 may also include redundant or backup portions to meet availability requirements in the event of a primary portion failure. External interfaces may also be provided to connect the central hub 102 to an external computer network or communication system, if desired, as appropriate for the particular functional division of local or remote functions.

As illustrated in fig. 2, the theatre subsystem 104 is in at least one and generally multi-theatre management configuration 132 controlled by theatre management 128. For example, theaters in some commercial markets are constructed as a theater complex with many auditoriums at one location, often referred to as a multi-auditorium theater. The stored compressed information may be transmitted to one or more auditorium modules 132 within a theatre complex.

The auditorium module 132 includes a cinema storage 136, a playback module 140, a decoder 144, as well as a projector 148 and a sound module 152. In operation, the theater storage device 136 contains compressed information on a storage medium. A different embodiment of a storage device is illustrated in fig. 7. Typically, the storage medium is physically transferred from the hub 102 to the theatre subsystem 104, although it is contemplated that portions of the information can be transferred from the hub 102 to the theatre subsystem 104. The storage medium may be one or more DVD disks 236 (FIGS. 7A and 7C), one or more removable hard disks 240 (FIG. 7B), an Internal Hard Disk (IHD)244 in the playback module (FIG. 7D), a JBOD module 248 (FIG. 8) containing a number of memory elements, or any combination thereof.

In embodiments using a DVD as the storage medium, multiple DVD disks 236 may be used. This embodiment is illustrated in fig. 7A. An average picture compression bit rate of about 40Mbps for the picture channel and an average two hour movie of about eight Mbps for the audio and control information requires approximately 45GB of storage space. Present day DVD-ROM storage forms range in storage capacity from about 4.5GB to about 18 GB. Storage capacities greater than about 9GB are dual-sided disks that must be flipped to read the second side of the disk. Thus, even if a high storage capacity DVD-ROM disk is realized, a two-hour movie requires the use of a plurality of DVD-ROM disks for sufficient capacity.

As previously mentioned, the image information is preferably separated from the audio information. This embodiment is illustrated in fig. 7C. Image program 252 is stored on a separate storage medium without audio program 256. The storage medium may be a DVD disc or an RHD. There is no need to use the invention while processing audio programs. Keeping the audio program and the image program separate allows for synchronizing multiple languages from the audio program with the image program without having to reset the image program for each language. Furthermore, maintaining separate audio programs allows for support of a multi-channel configuration without the need to interleave multiple audio channels with the image program.

In addition to the image program 252 and the audio program 256, separate promotional programs 260 or promotional programs may be added to the system. The use of a separate promotional program 260 allows the promotional material to be updated without the need for a new feature image program. The promotional programming 260 may contain advertising, trailers, controls, and/or key information for the theatre subsystem 104.

The use of a removable hard disk as a storage medium offers several advantages, such as ease of copying and the possibility of a lower error rate. This embodiment is illustrated in fig. 7B. The stored information on the hard disk is easily copied by writing the information to the disk in a standard Personal Computer (PC) environment. Further, fewer removable hard disks are necessary due to the large storage capacity of the removable hard disks. The use of a hard disk reduces the likelihood of operational errors compared to other storage media. Removable hard disks are also more likely to maintain data integrity in the event of a harsh environment, such as rough handling during shipping or exposure to dust, dirt, noise, or other foreign objects.

In another embodiment illustrated in FIG. 7D, an Internal Hard Disk (IHD)244 and modem 264 are used in addition to other storage media. Storing information on IHD244 via modem 264 allows for the direct transfer of information to a theater over an existing communication system such as a telephone line, ISDN, cable modem, or DSL link. Updates such as to advertising and trailer information may be communicated over the telephone line and stored on IHD 244. The updated film could alternatively be shown in the theatre directly from the IHD, rather than from the promotional program disk. The delivery of advertising and trailer information updates via modem 264 links results in significant cost savings because publication and distribution costs of additional promotional program disks are avoided.

Another function of IHD244 is that it is a data integrity system. The IHD checks the information stored on the storage medium for data integrity before passing it to the playback module. The data integrity system checks the electronic identification for each block of data. If any CRC block fails during the checking process, or if a data block is lost, the play module uses the modem link to request retransmission of the erroneous data block. Upon request, the requested data block is stored on IHD 244. When the play back module plays back the program, the play back module accesses IHD244 to play back the requested data block at the appropriate time. Accessing relatively few data blocks is most useful for the efficiency and data rate relationship. If the error checking system finds that a large number of data blocks are corrupted, the error information indicator allows the user to determine whether the problem data is the basis for the physical distribution of the data disk.

The use of IHD244 and modem 264 is also advantageous for cryptographic keying material distribution. Keying material and other control information is communicated from conditional access management 124 to IHD244 by physically transferring data in a separate storage medium or using modem 264. The operating state, history and other information is in turn passed to the conditional access management 124. Although control information is transmitted from the central hub 102 and the theatre subsystem 104 is able to receive all of the communicated information, the theatre subsystem 104 selectively demodulates and stores only the received programs that are required by a particular theatre module 104.

If IHD244 has sufficient capacity or through the use of JBOD module 348, image programs, audio programs, and/or promotional programs may be uploaded from the storage medium to the IHD. The use of IHD244 allows the playback module to support dual-slice and other multi-program scheduling. Further, a particular feature may be projected on multiple display screens by uploading a program to multiple playout modules such that the feature is played back from the IHD244 of each playout module.

In an alternative embodiment shown in fig. 7E, a Local Area Network (LAN) interface 268 replaces the modem interface 264 illustrated in fig. 7D. In addition to performing functions related to the modem interface described above, the LAN interface 268 may connect one or more playback modules and/or connect to the theater management 128. A user interface (not shown) is coupled to the LAN interface and/or theater management 128 to allow a user to remotely control and monitor functions such as scheduling, control, and error monitoring of each of the playback modules, decoding modules, or image and sound modules. Further, it is contemplated that network management 120 may be coupled into LAN interface 268. LAN interface 268 also allows for the transfer of programming between playback modules.

FIG. 8 illustrates an embodiment using multiple DVD disks 272a, 272b … … 272n as storage media and a set of single play DVD disk players 276a, 276b … … 276 n. The set of single play DVD players 276a, 276b … … 276n play the stored information on their respective disks in a serial mode in a predetermined sequence. The stored information is provided by the switch 280 to a buffer 284, such as the FIFO RAM buffer 284 illustrated in fig. 8. The FIFO RAM buffer 284 is of sufficient capacity so that the decoder 144 and subsequent projectors 148 are not overloaded or underloaded with part of the information. In the preferred embodiment, the use of the FIFO RAM buffer 284 is particularly important when the DVD disks 272a, 272b … … 272n are read in serial mode. When reading DVD discs in serial mode, there is a delay of a few seconds in switching from one disc to another.

The stored data is then fed to the decoder 144 via a fibre channel interface. The switch 280, buffer 284 and fibre channel interface are controlled by the play out module CPU 292.

The set of single-play DVD players 276a, 276b … … 276n may also play in a parallel mode, as shown in fig. 9. In parallel mode, multiple DVD disk players 276a, 276b … … 276n play different portions of the compressed information and then reassemble the portions in the play module 140. The portions of the compressed information read from the DVD disk players 276a, 276b … … 276n are provided to a parallel read/de-striping mechanism 296 which fully sorts the portions of the compressed information. In the preferred embodiment, the de-striping mechanism 296 is a software module accessible to the playback module 140. As shown in fig. 9, the de-striping mechanism 296 is a software module that is accessed by the CPU292 of the playback module 140. The de-striping mechanism 296 may be in the CPU 292. The de-striping mechanism 296 also performs error detection functions to ensure error-free playback. The compressed information portion may contain redundant information in case a portion of the disk cannot be read or if some of the compressed information is damaged. In these cases, the de-striping mechanism 296 can use the redundant information to recreate any corrupted information. The spare information and sequence information are stored on separate DVD discs and read in parallel with other compressed information discs 272a, 272b … … 272 n.

In an alternative embodiment to either of the embodiments illustrated in fig. 8 and 9, a DVD-disc cartridge may be used instead of the set of single play DVD-disc players. As illustrated in fig. 10, DVD-disc cartridge 300 is similar in operation to known CD-disc cartridges. A plurality of disks are inserted into DVD cartridge 300. Software control in storage device 136, playback module 140, or CPU292 ensures that the disks are properly installed and accessed in the proper order. Multiple disks are fed into a single DVD player. The converter means 304 in fig. 8 controls which DVD disc is inserted into the DVD player. In the DVD-box embodiment, serial or parallel playback may be performed.

Fig. 11 illustrates the operation of auditorium module 132 using one or more Removable Hard Disks (RHDs) 308. It may be desirable to use more than one RHD308 for speed, capacity, and convenience reasons. When reading data continuously, some RHDs have a "prefetch" feature that predicts the next read command based on the history of recent commands. This prefetch feature is useful in that: the time required for reading continuous data of the disk is reduced. However, if the RHD receives an unexpected command, the time required to read non-sequential data from the disk may increase. In this case, the pre-fetch feature of the RHD may cause the random access memory of the RHD to be full, thus requiring more time to access the requested information. Therefore, having more than one RHD is advantageous for faster reading of a continuous data string, such as a picture program. Further, accessing a second set of information, such as audio programs, movie trailers, control information, or advertisements, on a separate RHD disk is advantageous in that: it takes more time to access such information on a separate RHD.

Thus, compressed information is read from one or more RHD308 into buffer 284. The FIFO RAM buffer 284 in the playback module 140 receives portions of the compressed information from the storage device 136 at a predetermined rate. The FIFORAM buffer 284 is of sufficient capacity so that the decoder 144 and subsequent projectors are not overloaded or underloaded with information. In the preferred embodiment, the FIFO RAM buffer 284 has a capacity of about 100 to 200 MB. The use of FIFO RAM buffer 284 is particularly important because there is a delay of a few seconds in switching from one disk to another.

The compressed information portion output from the FIFO RAM buffer is fed to the network interface 288, which provides the compressed information to the decoder 144. In the preferred embodiment, network interface 288 is a fibre channel decision loop (FC-AL) interface.

In an alternative embodiment not specifically illustrated, a switching network controlled by the theatre management 128 receives the output data from the playback module 140 and passes the data to a particular decoder 144. The use of a switched network allows the programming on any particular play out module 140 to be transferred to any particular decoder 144.

When viewing a program, the program information is retrieved from the storage device 136 and transmitted to the auditorium module 136 through the theatre management 128. The decoder 144 decrypts the data received from the storage device 136 using the secret key information provided only to authorized theaters and decompresses the stored information using a decompression algorithm that is the inverse of the compression algorithm used in the source generator 108. The decoder 144 converts the decompressed image information to a standard video mode (which may be analog or digital) for use by the projection system and displays the image via an electronic projector 148. The audio information is also decompressed and provided to the sound system 152 of the auditorium for playback with the image program.

Fig. 11 also illustrates a block diagram of the decoder 144. The decoder 144 processes the compressed/encrypted program to make it visually projected on a display screen or surface and audibly presented with the sound system 152. The decoder 144 is controlled by its controller 312 or through the theatre management 128 and includes at least one de-packetizer 316, a controller or CPU312, a buffer 314, an image decryptor/decompressor 320 and an audio decryptor/decompressor 324. The buffer temporarily stores information for the de-packetizer 316. All mounted on one or more circuit board components. The circuit board components may be mounted in a separate box mounted to or adjacent to the projector 148. Additionally, a cryptographic smart card 328 may be used to interface with the controller 312 and/or the image decryptor/decompressor 320 for transmission and storage of unit-specific cryptographic key information.

The depacketizer 316 identifies and separates individual control, image and audio packets from the playback module 140, the CPU312 and/or the theater management 128. Control packets may be passed to the theater management 128 as the image and audio packets are passed to the image and audio decryptor/decompressor systems 320 and 324, respectively. Read and write operations are to occur in the burst. Thus, using a large buffer 314 allows data to flow smoothly from the de-packetizer 316 directly to the projection device.

Theatre management 128 configures, securely manages, operates, and monitors theatre subsystem 104. This includes an external interface, image and audio decryption/decompression modules 320 and 324, together with projector 148 and sound module 152. Control information comes from the playback module 140, the CPU312, the theater management system 128, a remote control port, or a local control input such as a control panel outside of the auditorium module 132 housing or base. The decoder CPU312 may also manage the electronic keys assigned to each auditorium module 132. The preselected electronic cryptographic key assigned to auditorium module 132 is used in conjunction with electronic cryptographic key information inserted into the image and audio data to decrypt the image and audio information prior to the decompression process. In the preferred embodiment, the decoder CPU312 operates as a basic function or control element using a standard microprocessor inserted into the software of each auditorium module 132.

In addition, the decoder controller 312 is preferably configured to work with the theater management 128 or to transmit specific information to maintain a history of the shows occurring at each auditorium. Information about this performance history may then be transmitted to the hub 102 at a preselected time using a return link or via a portable medium.

The image decryptor/decompressor 320 takes the image data string from the depacketizer 316, decrypts and reassembles the original image for display on the display screen. The output of this operation typically provides standard analog RGB signals to the digital cinema projector 148. Decryption and decompression are typically performed in real-time, allowing for real-time playback of program material.

The image decryptor/decompressor 320 operates inversely with the image compressor 184 and the image encryptor 188 of the hub 102 to decrypt and decompress the image data string. Each auditorium module 132 may process and display different programs from other auditorium modules 132 in the same theatre subsystem 104 or one or more auditorium modules 132 may process and display the same program simultaneously. Alternatively, the same program may be displayed on multiple projectors, the multiple projectors delayed in time relative to each other.

The decryption process uses the previously provided unit-specific and program-specific electronic cryptographic key information in conjunction with the decrypted image information of the electronic key inserted into the data string. (the decryption process was described above with reference to fig. 4.) each theatre subsystem 104 is provided with the necessary cryptographic key information for all programs authorized to be shown on each auditorium module 132.

Authorization for a particular presentation system to show a particular program is managed using a multi-level cryptographic key. This multi-level key management typically uses electronic key values that are specific to each authorized theater management 128, a particular image and/or audio program, and/or a sequence of time-varying cryptographic keys within an image and/or audio program. A "auditorium-specific" electronic key, typically 56 bits or longer, is programmed into each auditorium module 132.

The programming may be implemented using several techniques for transmitting and displaying the key information used. For example, the return link discussed above may be used by a link that transmits cryptographic information from the conditional access management 124. Alternatively, smart card technology such as smart card 328, pre-programmed flash cards, and other known portable storage devices may be used.

For example, the smart card 328 may be designed so that this value, once loaded into the card, cannot be read from the smart card memory. Physical and electronic security measures are used to deter tampering with this key information and to detect attempted tampering or tampering. The key is stored in such a way that: it will be erased upon detection of attempted tampering. The smartcard circuitry includes a microprocessor core containing a software implementation of an encryption algorithm, typically the Data Encryption Standard (DES). The smart card can input the values provided to it, encrypt (or decrypt) these values with the DES algorithm on the card and the pre-stored auditorium-specific key and output the result. Alternatively, the smart card 328 may be used to simply pass the encrypted electronic key information to circuitry in the theatre subsystem 104 that will perform this key information processing for use in the image and audio decryption process.

The image program data string is subjected to dynamic image decompression using the inverse ABSDCT algorithm or other image decompression process symmetrical to the image compression used in the central hub compressor/encryptor 112. If the image compression is based on the ABSDCT algorithm, the decompression process includes variable length coding, inverse frequency weighting, inverse differential quadtree transformation, IDCT and DCT block combiner de-interleaving. The processing elements used for decompression may be implemented on specialized special hardware configured for this function, such as an ASIC or one or more circuit board components. Alternatively, the decompression processing element may be implemented as a standard element or as integrated hardware including different digital signal processors or programmable electronic devices or computers operating under the control of a particular functional software or firmware program. Multiple ASICs can be implemented to process image information and support high image data rates.

The decompressed image data undergoes digital-to-analog conversion and outputs an analog signal to the projector 148. Alternatively, a digital interface is used to transfer the decompressed digital image data to the projector 148, obviating the need for a digital to analog conversion process.

The audio decryptor/decompressor 324 takes the audio data string from the depacketizer 316, decrypts and reassembles the original audio for presentation on the cinema speakers or audio sound system 152. The output of this operation provides a standard line level audio signal to the sound system 152.

Similar to the image decryptor/decompressor 320, the audio decryptor/decompressor 324 reverses the operation of the audio compressor 192 and the audio encryptor 196 of the hub 102. Using the electronic key from cryptographic smart card 228 in conjunction with the electronic key inserted into the data string, decoder 324 decodes the audio information. The decrypted audio data is then decompressed.

Audio decompression is performed using a symmetric algorithm to that used for audio compression at the central hub 102. Multiple audio channels (if any) are decompressed. The number of audio channels is designed according to the multi-channel sound system of a particular auditorium or display system. Additional audio channels may be transmitted from the central hub 102 for improved audio programming for purposes such as multilingual audio tracks and audio prompts for the visually impaired. The system may also provide additional data channels synchronized with the image program for purposes such as multimedia special effects channels, subtitles, and special video cue channels for the hearing impaired.

As previously discussed, the audio and data channels are time synchronized with the image program or may be presented asynchronously without direct time synchronization. The image program may contain a single frame (i.e., still image), a sequence of single frame still images, or a sequence of short or long time moving images.

The audio channel is provided to an audio delay element, if necessary, which inserts a delay when the audio needs to be synchronized with the appropriate image frame. Each channel then passes through digital-to-analog conversion to provide what is referred to as a "line level" output to the sound system 152. That is, signals of appropriate analog levels and forms are generated from the digital data to drive the appropriate sound system. Line level audio outputs typically use standard XLR or AES/EBU connectors found in most cinema sound systems.

The projector 148 displays an electronic representation of the program on a display screen. High quality projectors are based on advanced technologies such as the liquid crystal light valve tube (LCLV) method of processing light or image information. The projector 148 receives image signals, typically in the form of standard red, green, and blue (RGB) video signals, from an image decryptor/decompressor 320. Information transfer to control and monitor the projector is typically provided over a digital serial interface from controller 312.

Referring back to fig. 11, the decoder chassis includes a fibre channel interface 288, a de-packetizer 316, a decoder controller or CPU312, an image decryptor/decompressor 320, an audio decryptor/decompressor 324, and a cryptographic smart card 328. The decoder chassis 144 is a secure, self-contained chassis that also houses the cryptographic smart card 328 interface, internal power and/or conditioning, cooling fans (if necessary), local control panel, and external interfaces. The local control panel may use any of various known input devices such as a membrane switch flat panel that plugs into an LED indicator. The local control panel typically uses or forms part of a linked access door to allow access to the interior of the chassis for service or maintenance. The door has a secure lock to prevent unauthorized access, theft or tampering with the system. During installation, a smart card 328 containing encryption key information (auditorium-specific key) is installed within the decoder chassis 144, firmly behind the locked front panel. The cryptographic smart card slot is accessible only in the closed front panel. The RGB signals output from the image decryptor/decompressor 320 to the projector 148 are securely connected within the decoder chassis 144 so that the RGB signals are not accessible when the decoder chassis 144 is mounted on the projector housing. A safety interlock may be used to prevent operation when the decoder 144 is not properly installed in the projector 148.

The sound system 152 plays the audio portion of the program on the cinema speakers. In the preferred embodiment, the sound system 152 receives up to 12 channels of standard form audio signals from the audio decryptor/decompressor 324, either in analog or digital form.

In another embodiment, the playout module 140 and decoder 144 are incorporated into a separate playout decoding unit 332. The combination of the play module 140 and the decode module 148 results in cost and access time savings: only a single CPU (292 or 312) is required to provide the functionality of both the play out module 140 and the decoder 144. The combination of the play out module 140 and decoder 144 also does not require the use of a fibre channel interface 288.

If multiple viewing locations are desired, information disposed on any of the storage devices 136 is used to transfer the compressed information for the individual image programs to the different auditoriums at preselected programmable offsets or delays relative to each other. These preselected programmable offsets are substantially zero or small when a single image program is presented substantially simultaneously at a selected plurality of auditoriums. At other times, these offsets may be set to any value from a few minutes to a few hours in order to provide a very flexible show schedule, depending on storage configuration and capacity. This allows the theatre complex to better address market needs such as first-run film show events.

Fig. 13 illustrates another embodiment of the invention. The user interface 344 allows direct control over the decoder 144, along with the projector 148 and the audio system 152. JBOD (hard disk drive) 348 comprises a magnetic storage medium, such as a bank of hard disk drives, that stores encrypted/compressed encoded signals for scheduled playback times at a designated auditorium. JBOD348 is designed to be scalable to efficiently support the storage needs of each theater. Further, each JBOD348 includes built-in redundancy to prevent loss of stored program information in the event of a storage unit failure. For example, each JBOD348 may be a rack-mounted system that is scalable to suit the different storage needs of each theatre system. The use of JBOD348 allows theater management 128 to dynamically deliver shows to different display screens in the theater complex, and also allows for scheduling of pre-feature shows. This is done in a highly flexible manner, useful for responding quickly to changing needs or market demands.

In the preferred embodiment, each JBOD348 is designed to have an amount of storage equal to that required to store a program at its auditorium location. In this way more than one film (double film) can be shown on the same display screen on the same day. In addition, sufficient storage is provided to allow the now "authorized show" programs to be stored before future show shows are authorized while they are still stored. This amount of storage available takes into account authorized programs for future shows that are transmitted hours, days, or weeks before the authorized play and show of the future program without affecting the now authorized program play and display capabilities. It is estimated that in terms of digital data storage capacity, a level of about 120GB of storage capacity per auditorium is used in this arrangement. This capacity assumption uses existing compression and imaging techniques, which can be changed to allow for reduced demand in the near future.

Disk storage space is dynamically allocated for each program loaded into JBOD 348. This concept is to serve larger theaters with multiple display screens because short and long programs average to a standard length of typically about two hours. As a criterion for single display screen cinema, the storage capacity should be sufficient to store the longest programs.

JBOD348 is also configured or configurable to operate in a "stripe" mode in which received data is striped across the arrays and temporarily stored in RAM buffer 349. That is, the received data to be stored is partially directed to a different hard disk during storage. Part of the input data is transferred to one hard disk, while the following part is transferred to the next hard disk and so on. After sufficient latency to allow the hard disk to write data, the particular disk may again be set to receive incoming data. Thus, the received data is divided into smaller portions or segments, each of which is stored at the maximum (or high) rate allowed by each hard disk on a separate hard disk, taking advantage of the input buffer or memory storage that may be provided in the hard disk input channel. This allows slower transmission rate devices to obtain data essentially in parallel and thus achieve very high transmission rates. This storage also provides error protection redundancy.

Storage of data on a hard disk or other storage device utilizes parity information, which allows programs to be reassembled once retrieved. That is, the providing apparatus reconnects the program parts at the time of retrieval or performance.

In a preferred embodiment, each JBOD348 is an array design based on a Redundant Array of Inexpensive Devices (RAID) with full data file recovery capability if a hard disk fails in sequence. JBOD348 provides status and warning indicators to help with troubleshooting or fault isolation. Remote status, control and diagnostics can also be used for this design.

The theater management 128 is illustrated in fig. 12. The theater management 128 provides operational control and monitoring of the entire show or theater subsystem 104 or one or more auditorium modules 132 within the theater complex. The theater management 128 can also use a program control mechanism or mechanism to generate groups of programs from one or more received individual image and audio programs scheduled to be shown at the auditorium system during authorized time intervals.

The theater management 128 includes a theater management processor 336 and may optionally include at least one modem 340 or other device that interfaces with a return link that conveys information back to the central hub 102. Theatre management 128 includes a video display element such as a monitor or user interface device such as a keyboard that may be located at the theatre complex manager's office, kiosk or any other suitable place that facilitates theatre operations.

Theatre management processor 336 is typically a standard business class computer. Referring to fig. 12 and 2, the theater management processor 336 communicates with the network management 120 and the conditional access management 124. In the preferred embodiment, the modem 340 is used to communicate with the central hub 102. Modem 340 is typically a standard telephone line modem that is housed in or coupled to the processor and connects to a standard two-wire telephone line to communicate back to central hub 102. In alternative embodiments, other low data rate communication methods such as the internet, private or public data networks, wireless or satellite communication systems may be used to communicate communications between the theater management processor 336 and the central hub 102. For these options, the modem 340 is configured to provide the appropriate interface structure.

Referring back to fig. 2, theater management 128 allows each auditorium module 132 to communicate with each storage device 136. The theatre management module interface may include buffer memory so that character sets of information can be transmitted at a high data rate from theatre storage 136 using theatre management interface 126 and processed at a lower rate by other elements of auditorium module 132.

The information communicated between theater management 128 and network management 120 and/or conditional access management 124 includes requests for retransmission of information portions of presence unmodified bit errors, monitoring and control information, operational reports and warnings and cryptographic key information received by theater subsystem 104. The transmitted information may be cryptographically protected to provide eavesdropping-like security and/or authentication and authorization.

Theatre management 128 can be configured to provide fully automatic operation of the display system including control of playback/display, security and network management functions. The theater management 128 can also provide control of peripheral theater functions such as ticketing reservations and sales, licensing operations, and environmental control. Alternatively, some control of the theatre operation may be supplemented with manual intervention. The theater management 128 can also interface with presence-specific control automation systems in the theater complex to control or coordinate these functions. It will be appreciated that the system used will depend on the available technology and the needs of the particular theatre.

The invention generally supports simultaneous playback and presentation of recorded programs on multiple display projectors through control of theater management 128 or network management 120. Furthermore, authorization for multiple plays of a program is often performed under the control of the theatre management 128 or network management 120 even though the theatre subsystem 104 only needs to receive a program once. Security management may control the length of time each program is allowed to be played and/or the number of plays.

Means for automatically storing and presenting programs are provided by automatic control of the theatre management 128 by the network management module 112. In addition, the use of control elements provides the ability to control certain preselected network operations from a location remote from the central facility. For example, a television or movie studio can automate and control the distribution of movies and other shows from a central location, such as a studio office, and make near-immediate changes to the show to account for rapid changes in market demand or reflections of the show or other reasons as understood in the art.

Referring back to fig. 2, the theatre subsystem 104 may be connected to an auditorium module 132 using a theatre interface network 126. The theatre interface network 126 comprises a local area network (electronic or fiber optic) that provides for the local delivery of programming at the theatre subsystem 104. The programming is stored in each storage device 136 and transmitted to one or more auditorium systems 132 of the theatre subsystem 104 via the theatre interface network 126. The cinema interface network 126 may be implemented with any of a number of standard local area network architectures that exhibit sufficient data transfer rates, connectivity, and reliability such as decision-loop, switching, or hub-oriented networks.

Still referring to fig. 2, each storage device 136 provides for local storage of program material that is authorized to be played and displayed. In one embodiment, the storage system is centralized at each theatre system. The cinema storage 136 allows the cinema subsystem 104 to perform presentation activities in one or more auditoriums and to be shared among several auditoriums at the same time.

Depending on capacity, the cinema storage 136 may store several programs at a time. The cinema storage equipment 136 may be connected with a local area network in such a way that: any program is played and performed on any authorized performance system (i.e., projector). The same program may also be played simultaneously on two or more presentation systems.

Accordingly, apparatus and methods for decoding, decompressing and decrypting image and/or audio information are provided. The apparatus and method allow for flexible arrangement of prints and advertisements, integration of audio and image signals, and ease of implementation of security measures, among other features and advantages.

The previous description of the preferred embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (109)

1. An apparatus in which an encoded signal representing an image in compressed and encrypted form on a storage medium and transmitted thereto is processed to enable display of the image, the apparatus comprising:

a storage device configured to receive a storage medium; and

a decoder configured to receive a compressed encrypted encoded signal from a storage medium, the decoder comprising

A decryptor configured to decrypt the compressed encrypted encoded signal; and

a decompressor configured to receive the compressed encoded signal from the decryptor and decompress the compressed encoded signal to enable display of the image.

2. The apparatus of claim 1, wherein the encoded signal further comprises an encoded signal representing at least one audio program,

wherein the storage device is further configured to receive a storage medium further containing an encrypted compressively-encoded audio signal representing at least one audio program;

wherein the decryptor is further configured to receive the encrypted compression-encoded audio signal from the storage medium and decrypt the encrypted compression-encoded audio signal; and

wherein the decompressor is further configured to receive the compression-encoded audio signal from the decryptor and decompress the compression-encoded audio signal to enable playback of the at least one audio program.

3. The apparatus of claim 2 wherein the decoder is configured to decrypt and decompress the encoded image signal and the audio program in a mutually independent non-contiguous manner.

4. The apparatus of claim 1, wherein the decompressor is configured to decompress the compressed encoded signal using an inverse adaptive block size discrete cosine transform compression technique.

5. The apparatus of claim 2 wherein the decompressor is configured to decompress the compressed encoded audio program at a variable rate.

6. The apparatus of claim 2, wherein the graphics signal is encoded to form at least one image program, and further comprising a discriminator, wherein the decompressor connects the discriminator to one or more audio programs having the at least one image program.

7. The apparatus of claim 2 wherein the encoded image signals and audio programming are transmitted to the storage medium in data packets, the decompressor further comprising a de-packetizer configured to extract the encoded image signals and audio programming from the data packets.

8. The device of claim 2, wherein the storage device is further configured to receive a device-specific key, and wherein the decrypter is further configured to decrypt the compressed encrypted encoded signal conditioned on the determination of the device-specific key.

9. The apparatus of claim 8, wherein the apparatus specific key is stored on a key storage medium separate from the image or audio encoded signal.

10. The apparatus of claim 9, wherein the key storage medium is a smart card.

11. The apparatus of claim 9, wherein the key storage medium is a magnetic disk.

12. The apparatus of claim 8, wherein the apparatus specific key is transmitted.

13. The apparatus of claim 8, further comprising means for indicating a time interval over which the device-specific key is valid and for ensuring that the device-specific key is used only during the time interval.

14. The apparatus of claim 13, wherein the device-specific key is rewritten from the key storage medium after expiration of the time interval.

15. The apparatus of claim 2, wherein the encoded signal further comprises at least one watermark, wherein the watermark is perceptually unnoticeable during playback of the decompressed image signal or the audio encoded program at a predetermined normal transmission rate, but is perceptible when the decompressed image signal and the audio encoded program are displayed at a rate substantially different from the normal rate.

16. The apparatus of claim 15, wherein the watermark is configured to identify display time and location information associated with the encoded image signal or audio program after decompression.

17. The apparatus of claim 2, further comprising theater management, wherein the theater management is configured to send control signals to and receive status information from the storage device and the decoder.

18. The device of claim 2, wherein the device is configured to establish a connection, wherein the connection is configured to send and receive information from outside the device.

19. The apparatus of claim 18, wherein the information comprises control and status information.

20. The apparatus of claim 18 wherein the information comprises updates to the encoded image signal and the audio program.

21. The apparatus of claim 18, wherein the connection comprises a dedicated telephone data link.

22. The apparatus of claim 18 wherein the connection comprises a dial-up telephone data link.

23. The apparatus of claim 18, wherein the connection comprises a packet-type data link.

24. The apparatus of claim 18 wherein the connection comprises an internet based link.

25. The apparatus of claim 18, wherein the connection comprises a wireless data link.

26. The apparatus of claim 18, wherein the connection comprises a satellite-based data link.

27. The apparatus of claim 2, wherein the storage medium comprises at least one optical storage medium.

28. The apparatus of claim 27, wherein the storage medium comprises a plurality of optical storage media, and wherein the encoded image signal and the encoded audio program are stored non-contiguously on the plurality of optical storage media.

29. The apparatus of claim 27 wherein the encoded audio program is stored on a separate optical storage medium than the encoded image signal.

30. The apparatus of claim 27 further comprising encoded signals representing promotional information, and wherein the encoded signals representing promotional information are stored on a separate optical storage medium than the encoded image signals and the encoded audio program.

31. The apparatus of claim 27, wherein the optical storage medium comprises at least one DVD disc.

32. The apparatus of claim 2, wherein the storage medium comprises at least one magnetic storage medium.

33. The apparatus of claim 32 wherein the storage medium comprises a plurality of magnetic storage media and the encoded image signals and the encoded audio program are stored non-contiguously on the plurality of magnetic storage media.

34. The apparatus of claim 32 wherein the encoded audio program is stored on a separate magnetic storage medium than the encoded image signal.

35. The apparatus of claim 32 further comprising encoded signals representing promotional information, and wherein the encoded signals representing promotional information are stored on a separate magnetic storage medium than the encoded image signals and the encoded audio program.

36. The apparatus of claim 32, wherein the magnetic storage medium comprises at least one removable hard disk.

37. The apparatus of claim 32, wherein the magnetic storage medium comprises at least one JBOD module, wherein the JBOD module comprises at least one storage portion.

38. The apparatus of claim 2 further comprising a buffer synchronized with the playback of the encoded image signal and the audio program.

39. The apparatus of claim 2 wherein the storage device comprises means for using the discriminator information to concatenate different preselected portions of the encoded image signal or the encoded audio program with different preselected portions of the storage medium.

40. The apparatus of claim 2 wherein the storage device further comprises means for providing parallel stripe information to enable the encoded image signal or encoded audio program to be accessed at a desired data transmission rate and to provide error protection redundancy.

41. The apparatus of claim 2, wherein the at least one local area network interface interconnects at least the storage device, the decryptor, and the decompressor.

42. The apparatus of claim 41, wherein the network interface comprises an Ethernet network.

43. The apparatus of claim 2 wherein the encoded image signal is provided in the form of at least one image program in the form of either individual still frames or a series of frames displayed as a variable length motion picture.

44. The apparatus of claim 2, wherein the encoded image signals and audio programs stored on the storage medium are copied to at least a second storage medium to facilitate multiple playback of the encoded image signals and audio programs.

45. The apparatus of claim 44 wherein updates to the encoded image signal and the audio program are stored on the at least one second storage medium.

46. The apparatus of claim 45, wherein the at least one second storage medium is an internal hard disk.

47. The apparatus of claim 2 further comprising means for archiving and maintaining the encoded image signal and the encoded audio program play history.

48. The apparatus of claim 2 wherein the encoded signal further comprises an encoded signal representing a hint track, wherein the hint track indicates the particular portion of the program in which the connection information is located.

49. The apparatus of claim 2 further comprising a player, wherein the player is configured to distribute the encoded signals at preselected programmable offsets in time relative to each other.

50. The apparatus of claim 49 wherein the preselected programmable offset is substantially zero such that the encoded image signal is processed to cause multiple displays of the image at substantially the same time.

51. The apparatus of claim 1, further comprising a projector configured to cause an image represented by the encoded signal to be displayed.

52. The apparatus of claim 2, further comprising an audio player configured to play audio programming in synchronization with the presentation of the image.

53. A method in which processing of an encoded signal representing an image in compressed and encrypted form on a storage medium and transmitted thereto initiates display of the image, the method comprising the steps of:

retrieving the compressed encrypted encoded signal from the storage medium;

decrypting the encrypted encoded signal to generate a compressed encoded signal; and

the compressed encoded signal is decompressed to enable image display.

54. The method of claim 53, wherein the encoded signal further comprises an encoded signal representing at least one audio program, wherein:

the retrieving step further comprises retrieving an encrypted compressed encoded signal representing at least one audio program;

the step of decrypting further comprises decrypting the compressed encrypted encoded signal representing the at least one audio program to produce a compressed encoded signal representing the at least one audio program; and

the step of decompressing further comprises decompressing the compressed encoded signal representing the at least one audio program to enable image display.

55. The method of claim 54 wherein the steps of decrypting and decompressing the encoded image signal and the audio program occur in a mutually independent non-contiguous manner.

56. The method of claim 54, wherein the step of decompressing uses an inverse adaptive block size discrete cosine transform compression technique.

57. The method of claim 54, wherein the step of decompressing occurs at a variable rate.

58. The method of claim 54, further comprising the steps of:

combining the encoded graphics signals to form at least one image program; and

one or more audio programs are connected with at least one image program.

59. The method of claim 54 wherein the encoded image signals and audio programs are stored on the storage medium in data packets and the step of decompressing further comprises extracting the encoded image signals and audio programs from the data packets.

60. The method of claim 54, further comprising the step of retrieving the private key, wherein the step of decrypting occurs under certain conditions of the private key.

61. The method of claim 60, wherein the private key is stored on a key storage medium separate from the image encoded signal or the audio program.

62. The method of claim 61, wherein the key storage medium comprises a smart card.

63. The method of claim 61, wherein the key storage medium comprises a magnetic storage medium.

64. The method of claim 61, wherein the key storage medium comprises an optical storage medium.

65. The method of claim 60 wherein the private key is transmitted.

66. The method of claim 60, further comprising the step of indicating a time interval over which the private key is valid and ensuring that the private key is only used for the time interval.

67. The method of claim 66, further comprising the step of rewriting the private key from the key storage medium after expiration of the time interval.

68. The method of claim 54, further comprising the step of providing at least one watermark that is perceptually unnoticeable during playback of the decompressed image signal or the audio encoded program at a predetermined normal transmission rate, but perceptible when the decompressed image signal and the audio encoded program are displayed at a rate substantially different from the normal rate.

69. The method of claim 68, wherein the watermark identifies display time and location information associated with the encoded image signal or audio program after the decompressing step.

70. The method of claim 54, further comprising the step of providing a theater manager, wherein the theater manager transmits and receives status and control information regarding the storing, decrypting and decompressing steps.

71. The method of claim 67, further comprising the step of establishing a link to transmit and receive information.

72. The method of claim 71, wherein the information comprises status and control information.

73. The method of claim 71 wherein the information comprises updates to the encoded image signal and the audio program.

74. The method of claim 71, wherein the connection comprises a dedicated telephone data link.

75. The method of claim 71 wherein the connection comprises a dial-up telephone data link.

76. The method of claim 71, wherein the connection comprises a packet-type data link.

77. The method of claim 71, wherein the connection comprises an internet-based link.

78. The method of claim 71, wherein the connection comprises a wireless data link.

79. The method of claim 71, wherein the connection comprises a satellite-based data link.

80. The method of claim 54, wherein the storage medium comprises at least one magnetic storage medium.

81. The method of claim 80, wherein the storage medium comprises a plurality of magnetic storage media, and the encoded image signal and the encoded audio program are stored non-contiguously on the plurality of magnetic storage media.

82. The method of claim 80 wherein the encoded audio program is stored on a separate magnetic storage medium than the encoded image signal.

83. The method of claim 80 further comprising encoding signals representing promotional information, and wherein the encoded signals representing promotional information are stored on a separate magnetic storage medium than the encoded image signals and the encoded audio program.

84. The method of claim 80 wherein the storage medium comprises at least one DVD disc.

85. The method of claim 80, wherein the storage medium comprises at least one removable hard drive.

86. The method of claim 80, wherein the storage medium comprises at least one JBOD module.

87. The method of claim 80 further comprising buffering the encoded image signal and the audio program during playback to synchronize with the encoded image signal and the audio program.

88. The method of claim 54 further comprising the step of concatenating different preselected portions of the encoded image signal or the encoded audio program with different preselected portions of the storage medium.

89. The method of claim 54 further comprising providing parallel stripe information to enable the encoded picture signal or the encoded audio program to be accessed at a desired data transmission rate and to provide error protection redundancy.

90. The method of claim 54 further comprising the step of providing at least one local area network interface.

91. The method of claim 91, wherein the network interface comprises an ethernet network.

92. The method of claim 91 wherein the encoded image signal is provided in the form of at least one image program, wherein the image program is in the form of either individual still frames or a series of frames displayed as a variable length motion picture.

93. The method of claim 54 further comprising the step of copying the encoded image signals and audio program onto at least a second storage medium to facilitate multiple plays of the encoded image signals and audio program.

94. The method of claim 94, further comprising the step of storing updates to the encoded image signal and the audio program on at least a second storage medium.

95. The method of claim 54, further comprising the step of archiving and maintaining a history of the playing of the encoded image signals and the encoded audio program.

96. The method of claim 52, further comprising the step of indicating the specific portion of the encoded signal or audio program in which the linking information is located.

97. The method of claim 54, further comprising the step of displaying the encoded signal representing the image.

98. The method of claim 54 further comprising the step of distributing the encoded signals at preselected programmable offsets in time relative to each other.

99. The method of claim 99 wherein the preselected programmable offset is substantially zero to enable the encoded image signal to be processed so that the image has multiple displays at substantially the same time.

100. The method of claim 98 further comprising the step of playing the audio program in synchronization with the presentation of the image.

101. An apparatus in which an encoded signal representing an image in compressed and encrypted form on a storage medium and transmitted thereto is processed to initiate display of the image, the apparatus comprising:

means for receiving a storage medium; and

means for receiving a compressed encrypted encoded signal from a storage medium;

means for decrypting and decrypting the compressed encrypted encoded signal; and

means for receiving the compressed encoded signal from the decryptor and decompressing the compressed encoded signal to enable display of the image.

102. The apparatus of claim 102, wherein the encoded signal further comprises an encoded signal representing at least one audio program, said apparatus further comprising:

means for receiving an encrypted compression encoded audio signal representing at least one audio program;

means for decrypting the encrypted compressed encoded audio signal; and

means for decompressing the compressed encoded audio signal to enable playback of the at least one audio program.

103. The apparatus of claim 103, wherein the decompressing means decompresses using an inverse adaptive block size discrete cosine transform compression technique.

104. The apparatus of claim 103, wherein the means for decompressing is configured to decompress the compressed encoded audio program at a variable rate.

105. The apparatus of claim 103 wherein the encoded image signals and audio programs are transmitted to the storage medium in packets, and wherein the means for decompressing further comprises means for de-packetizing the encoded image signals and audio programs from the packets.

106. An apparatus in which an encoded signal representing an image in compressed and encrypted form on a storage medium and transmitted thereto is processed to initiate display of the image, the apparatus comprising:

a storage device configured to receive a storage medium; and

a decoder configured to receive a compressed encrypted encoded signal from a storage medium, the decoder comprising

A decryptor configured to decrypt the compressed encrypted encoded signal; and

a decompressor configured to receive the compressed encoded signal from the decryptor and decompress the compressed encoded signal to enable display of the image, the decompressor inversely adapting the block size discrete cosine transform compression technique.

107. The apparatus of claim 107, wherein the encoded signal further comprises an encoded signal representing at least one audio program,

wherein the storage device is further configured to receive a storage medium further containing an encrypted compressively-encoded audio signal representing at least one audio program;

wherein the decryptor is further configured to receive the encrypted compression-encoded audio signal from the storage medium and decrypt the encrypted compression-encoded audio signal; and

wherein the decompressor is further configured to receive the compression-encoded audio signal from the decryptor and decompress the compression-encoded audio signal to enable playback of the at least one audio program.

108. An apparatus in which an encoded signal representing an image in compressed and encrypted form on a storage medium and transmitted thereto is processed to initiate display of the image, the apparatus comprising:

a storage device configured to receive a storage medium and a device-specific key; and

a decoder configured to receive a compressed encrypted encoded signal from a storage medium, the decoder comprising

A decryptor configured to decrypt the compressed encrypted encoded signal under conditions determined by the device-specific key; and

a decompressor configured to receive the compressed encoded signal from the decryptor and decompress the compressed encoded signal to enable display of the image.

109. The apparatus of claim 109, wherein the encoded signal further comprises an encoded signal representing at least one audio program,

wherein the storage device is further configured to receive a storage medium further containing an encrypted compressively-encoded audio signal representing at least one audio program;

wherein the decryptor is further configured to receive the encrypted compression-encoded audio signal from the storage medium and decrypt the encrypted compression-encoded audio signal; and

wherein the decompressor is further configured to receive the compression-encoded audio signal from the decryptor and decompress the compression-encoded audio signal to enable playback of the at least one audio program.