CN100380968C - Device and method for decoding digital image and audio signals - Google Patents

Abstract

An apparatus and method for decoding of encoded signals representing at least image information from a storage medium is claimed. A storage device (136) is configured to receive the storage medium. A decoder (144) is configured to receive the compressed encrypted encoded signals from the storage medium, and send the signals to a decryptor (320/324). The decryptor (320/324) is configured to decrypt the compressed encrypted encoded signals, and send the signals to a decompressor (320/324). The decompressor (320/324) is configured to receive the compressed encoded signals from the decryptor and to decompress the compressed encoded signals to enable display of the image.

Description

Device and method for decoding digital image and audio signals

Background of the invention

I. Field of Invention

This invention relates to encoding digital and audio images. More specifically, the invention relates to apparatus and methods 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 programming from a central device to multiple display projectors or display systems.

II. Description of related technologies

For decades, the motion picture industry has relied on the reproduction, distribution, and projection of celluloid film to deliver original programming material to geographically diverse theaters across the country and around the world. For the most part, the methods and mechanisms of film material distribution have remained relatively unchanged.

The current process of film duplication and distribution is illustrated in FIG. 1 . Film duplication usually starts with special photographic negatives. In the movie studio 50, a movie editor 52 produces a master copy of the movie after the process of creating the original movie takes place. From this master film copy, the film reproduction component 54 produces what is called a release film, from which release versions (called "positives") are mass-produced. Depending on the size of the distribution or the desired number of copies of the movie distribution, there may be more intermediate steps or multiple copies produced at each stage. As exemplified by theater 56, the feature film is distributed to different theaters by courier and other physical means. In theater 56, the film is shown by using film projector 58 to reflect images from the film onto the display screen surface. In this conventional system, a multi-track audio program is generally produced by the audio editing system 51 and printed on film together with the movie image so that the audio tracks can be played synchronously with the movie on the theater sound system 57 in the theater projection system.

While the distribution process shown in Figure 1 works well, it has inherent limitations. Due to the use of film celluloid material and the limited bandwidth of the film medium, there are limitations in the ability to deliver high fidelity multi-channel audio programs. Thus, there is a high expense in making a large number of copies of the film, which can cost several hundred dollars per feature length film. There is also cost, complexity, and delay associated with physically distributing large cylinders of celluloid film to a large and growing number of theater locations. Also, a growing trend in the movie theater industry is the development of so-called "multiple" theater locations, in which multiple auditoriums are co-located or located within a single theater location. In multiple complexes, each auditorium can show films at the same time as other auditoriums are showing films.

Due to the large number of copies being made, it is becoming increasingly difficult to prevent illegal copying and theft of materials. It is estimated that the film industry loses billions of dollars in lost revenue each year due to piracy and theft. In addition, copied video material will gradually degrade over time due to dust accumulation, wear and tear, thermal changes and other known factors. Finally, overhead and other costs are also included in the progressive breakdown of film material, which can contain controlled hazard material.

Emerging technologies are making it possible to provide alternatives to today's film distribution problems. For example, satellite transmission methods are now available, although they are not currently commercially viable for distribution of high quality audio/video (AV) material. Since the distribution of film programs is essentially a special type of continent-wide broadcasting, the method of satellite distribution, with its inherent advantages, seems generally appropriate for film distribution for such wide-area broadcasting. However, in order to transmit high-quality AV signals in real time, the required data rate (in bits per second) is on the order of 1.5 billion bits per second. This high data rate requires the capacity of an entire satellite to transmit a single program, which is very expensive. In addition, alternative distribution technologies do not yet provide the image quality and projection brightness achieved with celluloid film. Competing technologies often involve recording audio/video (AV) signals on various magnetic or optical media for display on video monitors, televisions or projection devices. These technologies do not provide video quality due to bandwidth limitations.

In addition to the ability to transmit the necessary information via satellite, the received information must be displayed with high-quality projectors, which was not available before. Additionally, satellite-based transmission and receiver systems are expensive and a fundamental change from existing methods of movie distribution and display. It can be felt that such a radical change may not have been commercially acceptable from the outset.

Advances in digital technology have also led to a revolutionary distribution concept whereby program material is stored electronically in digital form rather than on optical film media. Digitized images may be distributed on various magnetic media, or compact discs, or transmitted by wire, 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 18GB. The DVD-ROM storage format with a storage capacity greater than about 9GB is implemented on double-sided disks. Strictly speaking, high-capacity DVD-ROM disks must be flipped manually to access the stored information from the second side of the disk.

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

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

To reduce the data rate requirements for high quality electronic image storage, compression algorithms were developed. One digital motion picture compression technique that provides significant compression while maintaining picture signal quality uses adaptively sized blocks and sub-blocks of data encoding discrete cosine transform (DCT) coefficients. This technique is hereinafter referred to as the Adaptive Block Size Discrete Cosine Transform (ABSDCT) method. The adaptive block size is chosen to take advantage of redundancy that exists due to information within a frame of image data. This technique is disclosed in US Patent No. 5,021,891 entitled "Adaptive Block Size Image Compression Method and System," assigned to the assignee of the present invention and incorporated herein by reference. DCT techniques are also disclosed in US Patent No. 5,107,345 entitled "Adaptive Block Size Image Compression Method and System," which is assigned to the assignee of the present invention and is incorporated herein by reference. In addition, the combined application of ABSDCT technology and differential quadtree transform technology is discussed in U.S. Patent No. 5452104 entitled "Adaptive Block Size Image Compression Method and System", which has also been assigned to the assignee of the present invention People, quoted here for reference. The systems disclosed in these patents use intraframe coding, whereby each frame of an image sequence is coded without regard to the contents of any other frames.

Distribution of film information in digital electronic form does increase the potential for rapid and low-cost reproduction without loss of quality. However, along with the "effort of copying" corresponding to digital technology, there is also encryption technology that ensures that information is encoded in a way that prevents useful information from being transmitted to unauthorized parties.

Technologies such as ABSDCT compression techniques, advanced projection equipment and electronic encryption methods offer the possibility of "digital cinema" systems. In general, digital cinema is concerned with the electronic distribution and display of high-quality film programs that have been converted into digital electronic representations for storage, transmission, and projection purposes. A digital cinema system would overcome many of the limitations of the existing film distribution process. Digital systems do not suffer from the outdated degradation that celluloid film suffers from. Further, the digital system virtually eliminates theft and illegal copying of celluloid film, and furthermore offers 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 film system.

Several points and issues remain to be resolved. New digital cinema systems require improved forms of protection to deter theater theft. Multiplex theater complexes have become larger in an effort to provide greater economic returns, resulting in more complex showing schedules and more places to show a particular film. This may require many additional electronic copies to be submitted to theaters for playback with existing technology at a corresponding complexity and operating cost.

Distribution channels and mechanisms are still determined by the old celluloid film reproduction and distribution techniques discussed above. New technologies are needed to take full advantage of proposed digital cinema processing to reduce copies, provide faster release to market, and update products in distribution while providing increased scheduling and distribution flexibility at a reasonable cost. At the same time, some filmmakers, studios and theater managers want to increase centralized control over release and distribution, and to be able to expand into newer markets. For example, it would be desirable to provide films and other audio-visual presentations with optional soundtracks in a more cost-effective manner to address the growing market of multilingual or alternate language audiences.

What is needed is the integration of a certain technology with apparatus and methods for encoding, encryption, storage and management of digital image 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 enable display of the image, the apparatus comprising a storage device configured to receive the storage medium; and A decoder configured to receive a compressed encrypted coded signal from a storage medium. The decoder further comprises a descrambler configured to decrypt the compressed encrypted coded signal and a decompressor configured to receive the compressed coded signal from the descrambler and decompress the compressed coded signal to enable image display, the decompressor using the reverse adaptive block Size DCT 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 enable display of the image, the method comprising the steps of retrieving the compressed encrypted encoded signal from the storage medium, compressing the encrypted The coded signal is decrypted to produce a compressed coded signal and the compressed coded signal is decompressed to enable image display. The decompression operation uses an inverse adaptive block size discrete cosine transform compression technique.

Accordingly, the apparatus and method provide for the decoding, decryption and decompression of image and/or audio information, generally in the form of program material. At a central facility or hub, program material is digitally compressed, encrypted and stored in preparation for distribution to one or more auditoriums or theater locations for large-screen presentation of the program. Program materials typically contain movie images, time-synchronized audio programs, and/or other related information, such as video cue tracks for visually impaired viewers, subtitles, commercials, or multimedia time cue channels for foreign language and/or hard of hearing audiences. Program material may be long in duration (eg, feature length movies), short in duration (eg, movie trailers or commercials), or still images (eg, for advertisements and promotions). Audio and other related programming need not be time-synchronized or stored with the image information, as is the case with background audio programs and advertisements.

At the central hub, program information is processed for distribution. Electrical audio and image signals from analog or digital inputs can be generated using source generators positioned at a central hub or at select locations. Source generators may include a telecine, which produces electronic image signals, and an audio reader, which produces electronic audio signals. Alternatively, the electronic signal may be provided directly from an electronic camera or other electronic source, such as a computer-based image generation system.

Electronic image and audio signals are then processed by a compressor/encryptor. Additionally, the compressor/encryptor can be located at a central hub or in the same facility as the source generator, such as a production soundstage. 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 50289 may be used. The storage medium can be any high-capacity electronic tape, magnetic or optical storage device, such as CD, DVD or hard disk or network attached storage. In addition, some information may instead be transmitted over wired, fiber optic, wireless or satellite communication systems. Audio signals can be compressed using the methods above or standard digital audio compression algorithms and stored on similar devices.

Encryption techniques include the use of time-varying electronic key values and/or sequences of digital control words, which are provided to authorized receivers and projectors. Additionally, digital signatures and "watermarks" can be added to image and/or audio signals. Watermarks are imperceptible to ordinary viewers, but can be used to identify sources of unauthorized copies of programs during non-real-time or still-frame playback analysis. The decryption information necessary to decrypt the image and/or audio information is generated at a separate decryptor unit using the secret algorithmic private key and the secure information sent to the theatre. Generally, image and audio signals are encrypted separately. By treating the visual and audio parts as separate programs, different audio programs can be combined with visual programs for various reasons, such as different languages.

Compressed and encrypted signals are also stored on storage media or provided for transmission from a central hub. If transmitted, the modulation/transmission technique can add forward error correction information and modulate the data stream for transmission. Transmission can be over any kind of wired or wireless communication, such as terrestrial cable, fiber optic cable, satellite, Internet or other methods.

The central hub further includes network management. Network management may include the control processor used to manage overall operations in both the encoder and theater subsystems, including control of storage, playback/display, security and overall monitoring/control and network management functions. Network management can work under central or distributed fully automatic control, semi-automatic control or human intervention.

Under the control of network management, program data and additional control information are stored and transmitted to the theater subsystem. Network management also includes a control method for informing the theater subsystem of the identity of the program being transmitted. In addition, control methods are provided to control the selective storage of each theater subsystem of received programs.

In the theater subsystem, storage devices receive storage media from the 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. Theater subsystems, such as theater management, use the communication path (from the theater subsystem to the central hub) to request retransmissions. The communication path can use the telephone network, satellite channel, Internet or any other communication method.

Under the control of the theater management, storage devices in the theater subsystem may provide for local centralized storage of program material. Storage devices may include storage media such as DVD discs, removable hard disks or hard disk serialization (JBOD) modules. A storage device can store several programs at a time. Storage devices can be connected via a Local Area Network (LAN) (electronic or optical) in such a way that any program can be played and staged on any authorized projector. The same program can also be played on two or more projectors at the same time. The program material is sent from the storage device to the designated auditorium through the local area network (LAN) using different LAN structures. For the purposes of this description, it is assumed that a LAN incorporating a central network switching fabric is used. However, other kinds of LAN structures are also possible for this subsystem.

After the playback module sorts the program material, the decoder decompresses and decrypts or decodes the program material. The decompression and decryption algorithms are based on the compression and encryption techniques used at the central hub. The decompressed/decrypted information is displayed by a projector in the auditorium, and the audio signal is presented by an electronic sound subsystem.

Theater management generally controls all aspects of projection operations, including storage of received programs, decompression and decryption of program signals, and display of program material. Theater management may also control when and/or how much each show is allowed to play. Alternatively, control of the display process may be located locally at the projector, at a remote control unit or under control of a central hub or other centralized component. Additionally, theater management can be configured to integrate projection operations and other theater operations such as ticketing, ticketing, promotions, signage, environmental control, lighting, sound system operations, and more. Each theater subsystem can also include multiple auditorium modules sharing the same storage and control functions for flexible and cost-effective studio options.

The use of digital encryption provides a solid measure of security. Use cryptography 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 by the theater subsystem. In addition to electronic security measures, physical security measures may provide additional protection of program material.

Physical security measures are essential to protect the decompressed/decrypted signal from being "sneaked" prior to projection on the cinema subsystem projector. In one embodiment, the decryption/decompression functionality is placed in a secure separate chassis that is physically placed or put into the projector in such a way that it is generally immovable without authorized access and physically The search for deciphered signals is prevented. Additionally, intrusion into the secure environment or chassis can cause deletion or wiping of cryptographic key information and additional deletion or alteration of digital data provided at any projector port to prevent copying.

Accordingly, devices and methods are provided for the decoding, decompression and decryption of digital and audio information, as well as for monitoring and controlling the management functions of such devices.

Brief description of the drawings

The features, objects and advantages of the invention will become apparent from the detailed description set forth hereinafter, when the invention and the features involved therein are taken together with the corresponding identified drawings, in which:

The figure is a block diagram of a traditional film distribution system;

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

Figure 3 is a block diagram of a movie-based source generator;

Figure 4 is a block diagram of a compressor/encryptor;

Fig. 5 is a block diagram of network management;

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

7A-E are block diagrams of storage devices;

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

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

Figure 0 is a block diagram of a storage device using a disk cartridge and a playback player;

Fig. 11 is a block diagram of a cinema subsystem using a removable hard disk as a storage device;

Figure 12 is a block diagram of theater management; and

Figure 13 is a block diagram of a theater subsystem using a JBOD module as a storage device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

This invention consists of apparatus and methods, sometimes referred to herein as "Digital Cinema", for the electronic decoding, decompression and decryption of audio/video, such as in theater systems, theaters, theater complexes and/or show systems Movie.

Digital cinema incorporates innovations in image and audio compression, projection technology, encryption methods, and many other areas. Digital cinema is designed to replace today's method of physically distributing celluloid film to each playback and projection venue such as a theater or remote auditorium. Digital cinema eliminates the need for celluloid film duplication and offers the potential for exceptional audio/video quality and built-in security measures. Shows can be transferred to theaters and stored on storage devices, such as removable hard drives (RHD) or digital versatile disks (DVD), for later screenings.

Exemplary theaters or theater complexes are for The following discussion is clear. Those skilled in the art will readily understand how this invention can be applied to other types of locations.

FIG. 2 illustrates a 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 theater subsystem 104 are similar in design to the design of pending U.S. Patent Application Serial No. 09/075,152, filed May 8, 1998, assigned to the same assignee as this invention, at This citation is for informational purposes.

In one embodiment, the image and audio data is compressed and stored on a storage medium and distributed from the hub 102 to the theater subsystem 104, typically for each theater in the network of venues that receive the image and audio information Or screening venues use a theater subsystem that includes some central equipment, as well as specific equipment for each show auditorium.

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

In theater subsystem 104 , theater management 128 controls theater management 132 . Based on control information received from theater management 132 , theater storage device 136 transmits the compressed information stored on the storage medium to playback module 140 . Playout module 140 receives compressed information from theater 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 the compressed information from the playback module 140 , performs decryption, decompression and formatting, and outputs the information to the projector 148 and the audio module 152 . Projector 148 plays information on the projector, and sound module 152 plays sound information on the sound system, both under the control of theater management 132 .

In operation, source generator 108 provides digital electronic images and/or programming to the system. Typically, source generator 108 receives film material and produces a tape containing digital information or data. Digitally scan film at very high resolutions to produce digitized copies of movies or other programs. Typically, the "telecine" process produces the image information while the well-known digital audio conversion process produces the audio portion of the program. The images being processed need not be supplied from the film, but may be individual pictures or still-frame type images, or a series of frames or pictures, including those shown as films of varying length. These images can be presented as a series or group to produce what is known as an image program. In addition, other materials such as video reminder channels for visually impaired viewers, subtitles or multimedia time reminder channels for foreign language and/or hearing impaired audiences may also be provided. Similarly, single or groups of speakers or recordings are used to create the desired audio program.

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

The digital image information or program is sent to 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 very high quality. In a preferred embodiment, the image source is compressed using ABSDCT techniques. ABSDCT compression techniques are proposed in the above mentioned US Patent Nos. 5,021,891, 5,107,345 and 5,452,104. 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 by one or more secure electronic methods.

Network management 120 monitors the status of compressor/encryptor 112 and directs compressed information from compressor/encryptor 112 to hub storage device 116 . Hub storage device 116 is comprised of one or more storage media (shown in Figure 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 as further described herein. Once the compressed information is stored on the storage medium, the storage medium is physically transferred to theater subsystem 104 and, in particular, to theater storage device 136 .

In an optional embodiment, the compressed image and audio information are stored independently of each other, not adjacent to each other or separately. That is, an apparatus is provided for compressing and storing audio programs corresponding to image information or programs but separated in time. This need is eliminated when using this invention to simultaneously process audio images. Predetermined recognizers or recognition mechanisms or schemes are used to combine corresponding audio and visual programs with each other when appropriate. This allows the linking of one or more preselected audio programs with at least one preselected video program at the time of the show or during the show, if desired. That is, the compressed audio is connected and synchronized at the time of the show, even though initially out of sync with the compressed image information.

Further, keeping the audio program and the video program separately allows for multiple languages from the audio program to the video program without resetting the video program for each language. Additionally, keeping the audio program separate allows for support of multi-speaker configurations, eliminating the need to interleave multiple audio tracks with the graphics program.

In addition to image programs and audio programs, separate promotional programs or promotional programs can be added to the system. Typically, promotional material changes with greater frequency than feature-length programming. The use of a separate promotional program allows promotional materials to be updated without requiring a new feature image program. Promotional programs contain information such as advertisements (slides, audio, puppet shows or the like) and trailers to be shown in theaters. Due to the high storage capacity of storage media such as DVD or RHD, thousands of pieces or strips of advertisements can be stored. High storage allows for specialization, as a specific slide, commercial or trailer can be shown in a specific theater for a targeted audience.

While FIG. 2 illustrates compressing information in storage device 116 and physically transporting the storage media to theater subsystem 104, it should be understood that compressed information, or portions thereof, may be transmitted to theater storage device 136 using any wireless or wired transmission method. Transmission methods include satellite transmission, well-known multipoint transmission, Internet access points, dedicated telephone lines or point-to-point fiber optic networks.

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

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

Since 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 magnetic tape 168 to the audio reader for digitization. In one embodiment, up to twelve tracks of digital audio are combined with digital images via multiplexer 176 . The multiplexed signal is stored together with the video program on a storage medium such as a high density digital video tape recorder 180 or similar high capacity digital storage system. As noted above, the audio program may alternatively be stored and processed separately from the video program, but time synchronization information may be included to properly account for the time at which the projection auditorium broadcast system fits in with the video program. Time synchronization information can be stored on the video program, audio program or a separate control program.

Although shown as part of a central hub, it should be appreciated that source generator 108 may be located at a different facility than central hub 102 . Other devices are suitable for generating digital signals from magnetic tape, magnetic or light sources. Alternatively, source generator 108 may comprise a digital camera with mounted magnetic or optical storage device or other image-generating digital device that directly produces digital source material (eg, for computer-generated images or special effects). The source generator 108 may also contain a digital system for still images, such as an optical scanner or an image converter for 35mm film or photographs. Thus, conventional or specialized studios, such as for special effects, or other equipment involved in image program preparation and display, can produce the desired digital material before transmitting it to hub 102 for further processing or transmission.

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

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

The digital image signal is passed to an image compressor 184 . In a preferred embodiment, image compressor 184 processes digital image signals using the ABSDCT technique described in the above-mentioned US Patent Nos. 5,021,891, 5,107,345, and 5,452,104.

In ABSDCT technology, the color input signal is generally YIQ mode, where Y is the brightness 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. Due to the low spatial sensitivity of the eye to color, the ABSDCT technique sub-samples the color (I and Q) components by a factor of two per direction in the horizontal and vertical directions. Therefore, each spatial segment of the image input is represented by four luma components and two chrominance components.

Each luma and chroma component is passed to a block interleaver. Typically a 16x16 (pixel) block is fed into a block interleaver, which sorts or organizes the image samples within each 16x16 block to produce blocks of data and composite sub-blocks for discrete cosine transform (DCT) analyze. The DCT operator is a method of converting a time-sampled signal into a frequency representation of the same signal. By converting to a frequency representation, it has been shown that DCT techniques can involve very high levels of compression because the quantizer can be designed to exploit the frequency distribution properties of the image. In a preferred embodiment, a 16×16 DCT is used for the first stage, four 8×8 DCTs are used for the second stage, 16 4×4 DCTs are used for the third stage, and the 64 2×2 DCTs are used for the fourth order.

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

For a 16x16 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 requiring 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 the image segment.

The selected blocks or combinations of sub-blocks are then sequenced as appropriate. The coefficient values of the DCT may then receive further processing such as frequency weighting, quantization and coding using known techniques (such as variable length coding), but not limited to, in preparation for transmission. 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 multiplexed audio information using standard digital audio compression algorithms. The compressed audio signal is provided to at least one audio encryptor 196 . Alternatively, the audio information can be delivered and used in an uncompressed but still digital mode.

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

At video and audio scramblers 192 and 196, program material is processed by scrambler/encryptor circuitry using time-varying electronic key information (typically changing several times per second). The encoded program information is then stored or transmitted, such as over an over-the-air wireless link, which is untranslatable to anyone who does not possess the associated electronic key used to encode the program material or digital data.

Encryption generally involves encoding of digital sequences or direct encryption of compressed signals. The words "encrypt" and "encode" are used interchangeably and are understood to mean the use of any cryptographic technique to encode, overwrite, or directly encrypt a string of numbers using said sequence produced by a secret digital value ("key") Any means of processing digital data strings from different sources such that recovery of the original data sequence is difficult without the use of a secret key value.

Each video or audio program may use specific electronic key information provided and encrypted by the venue or theater specific electronic key information for the theater or venue authorized to show the particular program. 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 sent to the authorized theater prior to the show. Of note are the potential transmission of stored program information days or weeks before authorized showtime begins, as well as the transmission or delivery of encrypted image or audio program keys just before authorized showtime begins. Encrypted program keys may also be transmitted using low data rate links or portable storage elements such as magnetic or optical media disks, smart cards, or other devices with erasable memory elements. Encrypted program keys may also be provided in such a manner as to control when a particular theater complex or auditorium is authorized to show a program.

Each theater subsystem 104 that receives an encrypted program key decrypts this value using its auditorium-specific key and stores the decrypted program key in a storage device or other secure memory.

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

Referring back to FIG. 4, in addition to encoding, the video encryptor 192 may add a "watermark" to the video program, which is usually digital in nature. This includes location-specific and/or time-specific visual indicators inserted in the program sequence. That is, watermarks are constructed to indicate authorized screening locations and times, if necessary in order to trace the source of illegal copies more effectively. Watermarks can also be programmed to appear at frequent but pseudo-random times during playback and be invisible to viewers. The watermark is perceptually imperceptible during the performance of the decompressed image or audio information at a preset transfer rate of normal. However, watermarks are perceptible when 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 a program is found, the digital watermark information can be read by the authorizing body, and the theater where the copy was made can be determined. Such watermarking techniques can also be applied or used to identify audio programs.

Both the compressed or encrypted image and audio signals are sent 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 stream information to be played at the theater subsystem 104 in time aligned form. The multiplexed signal is then processed by a program packetizer that groups the data to form program streams. By grouping the data, or forming "chunks," the program stream can be monitored during decompression by theater subsystem 104 (FIG. 2) for errors in receiving the chunks during decompression. The theater management 128 through the theater subsystem 104 may issue a request to get the errors displayed by the data block. Therefore, if an error exists, only a small portion of the program needs to be replaced, not the entire program. Requests for small chunks of data can be processed over wired or wireless links. This provides for enhanced reliability and efficiency.

In an alternative embodiment of the invention, the visual and audio portions of the program are treated as separate and distinct programs. In this way, instead of multiplexing image and audio signals using a multiplexer, image signals are individually packetized. In this embodiment, the audio program can be removed and the video program transferred, and vice versa. Strictly speaking, image and audio programs are assembled into a combined program only at play time. This takes into account different audio programs combined with image programs for different reasons, such as different languages, providing post-release updates or program changes, to fit within local social standards, etc. This ability to flexibly assign audio different multiplex programs to video programs is useful for reducing costs in changing programs that have been distributed and are committed to the larger multicultural market that is now used in the film industry.

Compressors 184 and 192, encryptors 188 and 196, multiplexer 200, and program packer 204 may be implemented by a compression/encryption module (CEM) controller 208, which is a software control set to perform the functions described herein processor. That is, they are configured as uniformly functioning hardware, including distinct programmable electronic devices or calculators working under the control of a software or firmware program. They may alternatively be implemented using some other technology, such as via an ASIC or via one or more circuit board integrations. That is, constructed as specialized hardware.

The video and audio program streams 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 can be implemented by programming a general purpose hardware device or computer to perform the required functions or by using specialized hardware. As described herein, network control is provided to CEM controller 208 from network management 120 (FIG. 2) over the hub internal network. The CEM controller 208 communicates with the compressors 184 and 192, the encryptors 188 and 196, the multiplexer 200 and the packetizer 204 using well-known digital interfaces, and controls the operation of these elements, and the CEM controller can also control and monitor Storage module 116 and data transmission between these devices.

Storage device 116 is preferably configured as one or more RHD, DVD discs, or other high capacity storage media, and is generally of a similar design to theater storage device 116 of theater subsystem 104 (FIG. 2). However, those of ordinary skill will appreciate that in some applications other media may be used. Storage device 116 receives compressed and encrypted images, audio, and control data from program packetizer 204 during the compression stage. The operation of storage device 116 is managed by CEM controller 208 .

Referring now to FIG. 5, network management 120 is illustrated. Network management 120 controls and manages hub 102 and, optionally, the entire digital theater system 100 , including control and monitoring of one or more components of theater system 104 . Centralized control enables the network management 120 to manage the entire operation of the system, including transmission, playback/display, security control and comprehensive network management functions. Alternatively, a distributed management system may be implemented in which processors in the show and theater systems control some theater functions.

Network management 120 includes at least one network management processor 212 , which is the central controller or "brain" of digital cinema system 100 . General network management 120 is based on standard platform workstations or similar programmable data processing hardware. Network management processor 212 manages the scheduling and security aspects of hub 102 . Under the control of network management, control information or program updates are transmitted from hub 102 to theater subsystem 104 prior to program showtime. Network management processor 212 also controls the rate at which programs are transmitted or delivered to theater subsystem 104 . Depending on the type of program and the design of the transmission channel or path, the transmission rate can be fixed or variable. For example, this could be based on the transmission rate for a particular data link. The data rate at which the program material is compressed and encoded may also vary from program to program, thereby providing different quality levels of compression.

The network management processor 212 interfaces with other parts of the hub through the hub's internal network, which is usually implemented using a standard multipoint network architecture. However, other known network designs and types including optical based links may be used. In a preferred embodiment, as discussed herein with reference to FIG. 6, Ethernet hub 216 of network management system 112 supports a hub-internal network.

Network management 120 may also include modem 220, which provides an interface to the Internet or theater network over 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. Modem 220 acts as a receiver for the return link communication path from theater to central hub 102 . For example, theater management 128 , illustrated in FIG. 7 , monitors the quality of the compression process of theater subsystem 104 and provides quality reports to network management system 120 . The return path may be used by the theater requesting retransmission of erroneous program data blocks from the central hub 102 . In addition, additional showings of the program or changes or updates to the program's material may be requested through this link. In alternative embodiments, the return path may be provided via a satellite channel or another low data rate communication method or via the Internet. In this case, other known docking devices or devices other than modem 220 are implemented in due course.

User interface 224 allows a user to directly control network management 112 and thus the entire hub 102 and/or theater subsystem 104 . A user can monitor the status of the hub 102 and dictate the timing of the different 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. User interface 224 is typically a personal computer with a monitor and keyboard interface.

Referring now to FIG. 6, a block diagram of hub internal network 228 is illustrated. Hub internal network 228 is the communication backbone for central hub 102 . The hub internal network 228 may be internally extended as an Ethernet local area network (LAN) running the IP protocol suite. Thus, hub internal network 228 physically interconnects compressor/encryptor 112 , storage device 116 , network management 120 , conditional access management 124 , and optionally theater management 128 to theater subsystem 104 of Ethernet hub 232 . 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 with external computer networks or communication systems, as appropriate, as appropriate for specific functional divisions for local or remote functions.

As illustrated in FIG. 2 , theater subsystem 104 employs at least one multiplex theater management fabric 132 , which is generally controlled by theater management 128 . For example, theaters in some commercial markets are structured as theater complexes with many auditoriums at one location, often referred to as multiplexes. The stored compressed information may be transmitted to one or more auditorium modules 132 within a theater complex.

Auditorium module 132 includes theater storage device 136 , playback module 140 , decoder 144 , and projector 148 and audio module 152 . In operation, theater storage device 136 contains compressed information on a storage medium. A different embodiment of a storage device is illustrated in FIG. 7 . Typically, storage media is physically transported from hub 102 to theater subsystem 104, although it is contemplated that some information may be transported from hub 102 to theater subsystem 104. The storage medium can be one or more DVD discs 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), containing many memory The element's JBOD module 248 (FIG. 8) or any group thereof.

In embodiments using a DVD as the storage medium, multiple DVD discs 236 may be used. This embodiment is illustrated in Figure 7A. An average two-hour movie with an average image compression bit rate of about 40 Mbps for the video channel and about eight Mbps for audio and control information requires approximately 45 GB of storage space. Today's DVD-ROM storage formats range in storage capacity from about 4.5 GB to about 18 GB. Storage capacities greater than approximately 9GB are double-sided disks, which must be flipped over 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 multiple DVD-ROM disks for sufficient capacity.

As mentioned earlier, it is best to separate image information from audio information. This embodiment is illustrated in Figure 7C. The video program 252 is stored on a separate storage medium without the audio program 256 . The storage medium can be DVD disc or RHD. This is not required when using this invention to simultaneously process audio programs. Keeping the audio program and the video program separate allows for multiple languages from the audio program to be synchronized with the video program without having to reset the video program for each language. Additionally, keeping the audio program separate allows for support of multi-channel configurations, eliminating the need to interleave multiple audio channels with the video program.

In addition to the visual program 252 and audio program 256, a separate promotional program 260 or promotional program may be added to the system. The use of a separate promotional program 260 allows promotional materials to be updated without requiring a new feature image program. Promotion 260 may contain advertisements, trailers, controls, and/or theater subsystem 104 key information.

The use of removable hard drives as storage media offers several advantages, such as ease of duplication and the possibility of lower error rates. This embodiment is illustrated in Figure 7B. Information stored on a hard disk is easily replicated by writing information to the disk in a standard personal computer (PC) environment. Further, due to the large storage capacity of the removable hard disk, fewer removable hard disks are necessary. The use of a hard disk reduces the possibility of operating errors compared to other storage media. Removable hard drives are also more likely to maintain data integrity in the event of harsh environments, such as rough handling during shipping or exposure to dust, dirt, noise, or other foreign matter.

In another embodiment illustrated in FIG. 7D, an internal hard disk (IHD) 244 and a modem 264 are used, among other storage media. Storing information on IHD 244 via modem 264 allows for delivery of information directly to the theater over existing communication systems such as telephone lines, ISDN, cable modem or DSL links. Updates such as advertisements and trailer information may be communicated over the telephone line and stored on the IHD 244 . Newer titles may optionally be shown in theaters directly from the IHD, rather than from promotional program disks. Delivery of updates to advertising and trailer information via the modem 264 link results in significant cost savings because the publication and distribution costs of additional promotional program disks are avoided.

Another function of the IHD244 is that it is a data integrity system. The IHD checks the information stored on the storage medium for data integrity before passing to the playback module. The data integrity system checks the electronic identification for each piece of data. If any CRC block fails during the check, or if a data block is lost, the playback module uses the modem link to request retransmission of the erroneous data block. Upon request, the requested data block is stored on the IHD 244 . When the playback module plays this program, the playback module will access the data block of the IHD244 and play the request at an appropriate time. In terms of availability and data rate, it is most useful to access relatively few data blocks. If the error checking system finds that a large number of data blocks have been damaged, the error message indicator allows the user to determine whether the problematic data has become the basis for the physical distribution of the data disk.

The use of IHD 244 and modem 264 is also advantageous for cryptographic keying material distribution. The cryptographic keying material and other control information is transferred from conditional access management 124 to IHD 244 by physically transferring data in a separate storage medium or using modem 264 . Operational status, history, and other information are in turn communicated to conditional access management 124 . Although control information is transmitted from central hub 102 and theater subsystem 104 is able to receive all transmitted information, theater subsystem 104 selectively demodulates and stores only the received programs required by a particular theater module 104 .

If the capacity of the IHD 244 is sufficient or through the use of the JBOD module 348, video programs, audio programs and/or promotional programs can be uploaded from the storage medium to the IHD. The use of IHD244 allows the playback module to support dual-chip and other multi-program scheduling. Further, a specific feature film can be shown on multiple display screens by uploading the program to multiple play modules so that the feature film can be played from the IHD 244 of each play 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 the functions described above with respect to the modem interface, the LAN interface 268 can be connected to one or more playback modules and/or to the theater management 128 . A user interface (not shown) is connected to the LAN interface and/or theater management 128 to allow the user to remotely control and monitor functions such as scheduling, control and error monitoring of each playback module, decoding module or image and sound module. Further, it is contemplated that network management 120 may be connected into LAN interface 268 . The LAN interface 268 also allows programs to be transmitted between playing modules.

Figure 8 illustrates an embodiment using multiple DVD discs 272a, 272b...272n as storage media and a set of single-play DVD disc players 276a, 276b...276n. The set of single-play DVD disc players 276a, 276b...276n play in a predetermined sequence in serial mode, playing the stored information on their respective discs. The stored information is provided via converter 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 subsequently the projector 148 will not be overloaded or starved of partial information. In the preferred embodiment, the use of FIFO RAM buffer 284 is especially important when DVD discs 272a, 272b...272n are read in serial mode. When reading DVD discs in serial mode, there is a delay of a few seconds when switching from one disc to another.

The stored data is then sent to decoder 144 via the Fiber Channel interface. The converter 280, buffer 284 and fiber channel interface are controlled by the playback module CPU 292.

The set of single-play DVD disc players 276a, 276b...276n can also play in parallel mode, as shown in FIG. In parallel mode, multiple DVD disc players 276a, 276b . . . The portions of the compressed information read from the DVD disc players 276a, 276b...276n are sent to a parallel read/destripe device 296 which completely sorts the portions of the compressed information. In a preferred embodiment, the destriping device 296 is a software module accessible to the playback module 140 . As shown in FIG. 9 , the stripping device 296 is a software module accessed by the CPU 292 of the playback module 140 . Destriping device 296 may be in CPU 292 . Destriping device 296 also performs an error detection function to ensure error-free playback. The compressed information section can contain redundant information in case parts of the disk become unreadable or if some compressed information is corrupted. In these cases, the destriping device 296 is able to regenerate any corrupted information from the redundant information. Spare information and sequence information are stored on separate DVD discs and read in parallel with other discs 272a, 272b...272n of compressed information.

In an alternative embodiment to either of the embodiments illustrated in Figures 8 and 9, a DVD case may be used in place of the set of single-play DVD players. As illustrated in FIG. 10, DVD case 300 is similar in operation to known CD cases. A plurality of disks are inserted into the DVD case 300 . Software control in storage device 136, playback module 140 or CPU 292 ensures that the disks are properly mounted and accessed in the proper order. Feed multiple disks into a single DVD player. Just like the converter means 304 in FIG. 8 controls which DVD disc is inserted into the DVD player. In the DVD case embodiment, serial or parallel playback can be performed.

FIG. 11 illustrates the operation of auditorium module 132 using one or more removable hard disks (RHD) 308 . For reasons of speed, capacity and convenience, it is desirable to possibly use more than one RHD 308. When reading data sequentially, some RHDs have a "prefetch" feature that predicts the next read command based on the history of recent commands. The usefulness of this prefetch feature is that it reduces the time it takes to read continuous data from disk. However, if the RHD receives unforeseen commands, the time required to read non-sequential data from the disk may increase. In this case, the RHD's prefetching feature may cause the RHD's random access memory to fill up, requiring more time to access the requested information. Therefore, having more than one RHD is advantageous for faster reading of continuous data streams such as video programs. Further, an additional advantage of accessing a second set of information, such as audio programs, movie trailers, control information or advertisements, on a separate RHD disk is that it takes more time to access such information on a separate RHD.

Thus, compressed information is read from one or more RHDs 308 into buffer 284 . FIFO RAM buffer 284 in playback module 140 receives partially compressed information from storage device 136 at a predetermined rate. FIFORAM buffer 284 is of sufficient capacity so that decoder 144 and subsequent projectors are not overloaded or starved of information. In the preferred embodiment, FIFO RAM buffer 284 has a capacity of approximately 100 to 200 MB. . The use of FIF0RAM buffer 284 is especially important due to the delay of several seconds when switching from one disk to another.

The portion of the compressed information output from the FIFO RAM buffer is sent to the network interface 288, which provides the compressed information to the decoder 144. In the preferred embodiment, network interface 288 is a Fiber Channel Arbitration Loop (FC-AL) interface.

In an optional embodiment not specifically illustrated, a switching network controlled by theater management 128 receives output data from playback module 140 and passes the data to specific decoder 144 . The use of a switched network allows programs on any particular playback module 140 to be transmitted to any particular decoder 144 .

When a program is viewed, program information is retrieved from storage device 136 and transmitted to auditorium module 136 by theater management 128 . Decoder 144 decrypts data received from storage device 136 using confidential 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 source generator 108 . Decoder 144 converts the decompressed image information to the standard video format used by the projection system (which may be in analog or digital form) and displays the image through electronic projector 148 . The audio information is also decompressed and provided to the auditorium's sound system 152 for playback with the video program.

FIG. 11 also illustrates a block diagram of decoder 144 . Decoder 144 processes the compressed/encrypted program to be visually projected on a display screen or surface and audibly projected by sound system 152 . Decoder 144 is controlled by its controller 312 or through theater management 128 and contains at least one depacketizer 316, controller or CPU 312, buffer 314, image decryptor/decompressor 320 and audio decryptor/decompressor 324. The buffer temporarily stores information for the depacketizer 316 . All mounted on one or more board components. The circuit board components may be mounted in a separate box mounted with 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 the transfer and storage of unit specific cryptographic key information.

Depacketizer 316 identifies and separates individual control, image and audio packets from playback module 140 , CPU 312 and/or theater management 128 . Control packets may be passed to theater management 128 as the image and audio packets are passed to image and audio decryptor/decompressor systems 320 and 324, respectively. Read and write operations will take place in character groups. Thus, using a large buffer 314 allows a smooth flow of data from the depacketizer 316 directly to the projection device.

Theater management 128 configures, securely manages, operates, and monitors theater subsystem 104 . This includes external interfaces, image and audio decryption/decompression modules 320 and 324, projector 148 and sound module 152 together. Control information comes from the playback module 140, the CPU 312, the theater management system 128, the remote control port or a local control input such as a control panel outside the auditorium module 132 housing or base. Decoder CPU 312 may also manage the electronic keys assigned to each auditorium module 132 . The preselected electronic cryptographic key assigned to the auditorium module 132 is used in conjunction with the electronic cryptographic key information inserted in the image and audio data to decrypt the image and audio information prior to the decompression process. In the preferred embodiment, the decoder CPU 312 runs using a standard microprocessor plugged into the software of each auditorium module 132 as a basic function or control element.

In addition, decoder controller 312 is preferably configured to work with theater management 128 or transmit specific information to maintain a historical record of the shows that took place in each auditorium. Information about this show history can then be used to transmit to the hub 102 at a preselected time using a return link or via portable media.

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

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

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

Authorize specific projection systems to perform specific shows using multi-level cryptographic key management. This multi-level key management typically uses electronic key values 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. An "auditorium specific" electronic key, typically 56 bits or longer, is programmed into each auditorium module 132 .

This programming can be accomplished 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 password information from conditional access management 124 . Alternatively, smart card technology such as smart cards 328, preprogrammed flash memory cards, and other known portable storage devices may also be used.

For example, the smart card 328 can be designed so that once this value is loaded into the card, it cannot be read from the smart card memory. Use physical and electronic security measures to prevent tampering with this key information and to detect attempted tampering or damage. The key is stored in such a way that it is erased in the event of a perceived tampering attempt. The smart card circuitry includes a microprocessor core that contains a software implementation of a cryptographic algorithm, usually 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, smart card 328 may be used to simply transfer encrypted electronic key information to circuitry in theater subsystem 104 that will process this key information for use in the image and audio decryption process.

The video program data string is decompressed on the fly using the reverse ABSDCT algorithm or other video decompression process commensurate with the video compression used in the central hub compressor/encryptor 112 . If the image compression is based on the ABSDCT algorithm, then the decompression process includes variable length coding, inverse frequency weighting, inverse differential quadtree transform, IDCT and DCT block combiner deinterleaving. The processing elements used for decompression may be implemented on specialized hardware configured for this function, such as an ASIC or one or more circuit board components. Alternatively, the decompression processing elements may be implemented as standard elements or integrated hardware comprising distinct digital signal processors or programmable electronics or computers operating under the control of special function software or firmware programs. 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 projector 148 . Alternatively, the digital interface is used to deliver decompressed digital image data to projector 148, avoiding the need for a digital-to-analog conversion process.

Audio decryptor/decompressor 324 takes the audio data stream from depacketizer 316 , decrypts and reassembles the original audio for presentation on theater 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 image decryptor/decompressor 320 , audio decryptor/decompressor 324 reverses the operations performed by audio compressor 192 and audio encryptor 196 of hub 102 . Using the electronic key from the cryptographic smart card 228 in conjunction with the electronic key inserted in the data string, the decoder 324 decodes the audio information. The decrypted audio data is then decompressed.

Audio decompression is performed using an algorithm symmetrical to that used for audio compression at the central hub 102 . Decompress multiple audio channels (if any). 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 delivered from the central hub 102 for improved audio programming for purposes such as multilingual audio tracks and audio prompts for visually impaired viewers. The system can also provide additional data channels synchronized with the video program for purposes such as multimedia special effects channels, subtitles and special video prompt channels for hard of hearing viewers.

As previously discussed, audio and data channels are time-synchronized with the video program or may be presented asynchronously without direct time synchronization. A picture program may contain a single frame (ie still picture), a sequence of single frame still pictures or a short or long time sequence of moving pictures.

If necessary, the audio channel is provided to an audio delay element, which inserts delays when necessary to synchronize the audio with the appropriate image frame. Each channel then goes through digital to analog conversion to provide what is referred to as a "line level" output to sound system 152 . That is, to generate a signal of the appropriate analog level and form from the digital data to drive the appropriate sound system. Line level audio output is usually using the standard XLR or AES/EBU connectors found in most theater sound systems.

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 (LCLV) method of processing light or image information. Projector 148 receives an image signal from image decrypter/decompressor 320, typically in the form of a standard red-green-blue (RGB) video signal. The transmission of information to control and monitor the projector is typically provided over a digital serial interface from the controller 312 .

Referring back to FIG. 11 , the decoder chassis includes fiber channel interface 288 , depacketizer 316 , decoder controller or CPU 312 , image decryptor/decompressor 320 , audio decryptor/decompressor 324 and cryptographic smart card 328 . The decoder chassis 144 is a secure, self-contained chassis that also houses the encrypted smart card 328 interface, internal power supply and/or regulation, cooling fans (if necessary), local control panel and external interfaces. The local control panel can use any of the various known input devices such as a membrane switch plane board plugged into an LED indicator. The local control panel usually uses or forms part of a link access door to allow access to the interior of the chassis for service or maintenance. The door has a secure lock to prevent unauthorized entry, theft or tampering of the system. During installation, a smart card 328 containing encrypted key information (auditorium specific key) is installed within the decoder chassis 144, securely behind the locked front panel. The password smart card slot is only accessible 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 cannot be accessed when the decoder chassis 144 is mounted on the projector housing. A safety interlock may be used to prevent operation of the decoder 144 if it is not properly installed in the projector 148 .

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

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

If multiple viewing locations are desired, information on any storage device 136 is configured to transmit compressed information for a single image program to different auditoriums with preselected programmable offsets or delays relative to time. These preselected programmable offsets are set to be substantially zero or very small when a single image program is performed substantially simultaneously in selected auditoriums. At other times, these offsets can be set to anything from a few minutes to hours depending on storage configuration and capacity in order to provide very flexible show scheduling. This allows theater syndicates to better address market demand for screening events such as first-run films.

Figure 13 illustrates another embodiment of the invention. User interface 344 allows direct control on decoder 144 , along with projector 148 and audio system 152 . JBOD (Back of Hard Disk) 348 contains magnetic storage media, such as a set of hard disk drives, which store encrypted/compressed encoded signals for scheduled play times in a designated auditorium. The JBOD348 is designed to be scalable to efficiently support the storage needs of each theater. Further, each JBOD 348 includes built-in redundancy to prevent loss of stored program information in the event of a storage unit failure. For example, each JBOD 348 can be a rack-mounted system that is expandable to suit the varying storage needs of each theater system. The use of JBOD 348 allows theater management 128 to dynamically route program showings to different displays in the theater complex, and also allows scheduling of pre-feature programs. This is done in a highly flexible manner, useful for quick response to changing needs or market demands.

In the preferred embodiment, each JBOD 348 is designed to have a storage capacity equal to its auditorium location storage program needs. 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 store future programming prior to their authorization for showing while still storing now "authorized showing" shows. This amount of storage available allows for future showings of licensed programs to be transmitted hours, days or weeks before future programs are authorized to be played and presented without affecting the ability to play and display present licensed programs. It is estimated that in terms of digital data storage capacity, a level of approximately 120 GB of storage capacity per auditorium is used in this arrangement. This capacity assumes the use of existing compression and image technology, which may change to allow for reduced needs in the near future.

Disk storage space is allocated dynamically for each program loaded into JBOD348. The concept is for larger theaters with multiple screens, since the average standard length for short and long shows is usually about two hours. As a guideline for single-display theaters, storage capacity should be sufficient for the longest programs.

JBOD 348 is also configured or configurable to operate in a "stripe" mode, in which data is striped across the array and temporarily stored in RAM buffer 349 as it is received. That is, the received data to be stored is partially directed to different hard disks during storage. Part of the input data is transferred to one hard drive, the next part to the next and so on. After a sufficient wait time to allow the hard disk to write data, the particular disk can be set to receive incoming data again. Thus, the received data is divided into smaller parts or fragments, each stored at the maximum (or high) rate allowed by each hard disk on separate hard disks, taking advantage of the input buffering or memory storage. This allows slower transfer rate devices to obtain data essentially in parallel and thus achieve very high transfer rates. This storage also provides error protection redundancy.

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

In a preferred embodiment, each JBOD 348 is based on a Redundant Array of Inexpensive Devices (RAID) array design with the ability to recover entire data files if a hard drive in the sequence fails. The JBOD348 provides status and warning indicators to aid in fault finding or error isolation. Remote status, control and diagnostics can also be used in this design.

Theater management 128 is illustrated in FIG. 12 . Theater management 128 provides operational control and monitoring of the entire show or theater subsystem 104 or one or more auditorium modules 132 within a theater complex. Theater Management 128 may also use a program control device or mechanism to generate program groups from one or more received independent video and audio programs that are scheduled to be shown in the auditorium system during authorized time intervals.

Theater management 128 includes theater management processor 336 and may optionally include at least one modem 340 or other device that interfaces with a return link that transmits information back to central hub 102 . Theater management 128 includes video display elements such as monitors or user interface devices such as keyboards, which may be located in the theater complex manager's office, ticket booth, or any other suitable location that facilitates theater operations.

Theater management processor 336 is typically a standard business class computer. Referring to FIGS. 12 and 2 , theater management processor 336 communicates with network management 120 and conditional access management 124 . In the preferred embodiment, modem 340 is used to communicate with central hub 102 . Modem 340 is typically a standard telephone line modem that resides in or is connected 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 theater management processor 336 and central hub 102 . For these options, 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 theater management module interface may include buffer memory so that information bursts may be transmitted from theater storage device 136 using theater management interface 126 at a high data rate and processed by other elements of auditorium module 132 at a lower rate.

Information communicated between theater management 128 and network management 120 and/or conditional access management 124 includes information about unmodified bit errors received by theater subsystem 104, monitoring and control information, operational reports and warnings, and cryptographic key information. Retransmitted request. The transmitted information may be cryptographically protected to provide wiretapping type security and/or verification and authentication.

Theater Management 128 may be configured to provide fully automated operation of the display system, including playback/display control, security and network management functions. Theater management 128 may also provide control of peripheral theater functions such as ticket reservations and sales, concession operations, and environmental control. Optionally, some control of theater operations may be supplemented with human intervention. Theater management 128 may also interface with certain presence control automation systems within the theater complex for control or adjustment of these functions. As you can see, the system used will depend on the technology available and the needs of a particular theater.

Through the control of theater management 128 or network management 120, the invention generally supports simultaneous playback and performance of recorded programs on multiple display projectors. In addition, under the control of theater management 128 or network management 120, even if theater subsystem 104 only needs to receive a program once, authorization to play the program multiple times is often performed. Security management can control the length of time and/or the number of plays allowed for each program.

Through automated control of theater management 128 by network management module 112, means are provided for automatically storing and presenting programming. In addition, the use of control elements has the ability to control specific preselected network operations from locations remote from the central facility. For example, a television or movie studio can automate and control the distribution of films and other shows from a central location, such as a studio office, and may change shows to account for rapid changes in market demand or in response to shows or other reasons understood in the art. Make almost instant changes.

Referring back to FIG. 2 , theater subsystem 104 may interface with auditorium module 132 using theater interface network 126 . Theater interface network 126 includes a local area network (electronic or fiber optic) that provides for local delivery of programming at theater subsystem 104 . Programs are stored in each storage device 136 and transmitted to one or more auditorium systems 132 of theater subsystem 104 via theater interface network 126 . Theater interface network 126 may be implemented with any number of standard local area network architectures that exhibit sufficient data transfer rate, connectivity, and reliability such as decision loop, switched, or hub-oriented networks.

Still referring to FIG. 2, each storage device 136 provides for local storage of program material authorized to play and display. In one embodiment, the storage system is centralized at each theater system. Theater storage device 136 allows theater subsystem 104 to run a show in one or more auditoriums and share it among several auditoriums at the same time.

Depending on capacity, theater storage device 136 may store several shows at a time. The theater storage device 136 can be connected using a local area network in such a way that any program can be played and presented on any authorized presentation system (ie, projector). The same program can also be played on two or more performance systems at the same time.

Accordingly, devices and methods for decoding, decompression and decryption of image and/or audio information are provided. This device and method allow for flexible arrangement of features and advertisements, integration of audio and video signals and easy implementation of security measures, among other features and advantages.

The above description of the preferred embodiments is provided to enable those skilled in the art to implement or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without the inventive effort of the invention. Thus, the 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 (61)

1. A device in which encoded image and audio signals representing a video program and a plurality of audio programs related to said video program in compressed and encrypted form on at least one storage medium are processed to enable display of said video program, Equipment includes: a storage device configured to receive a plurality of storage media that distributedly store portions of compressed encrypted encoded image and audio signals; and A decoder configured to receive portions of the compressed and encrypted encoded image and audio signals from the plurality of storage media and recombine portions of the image and audio signals, the decoder comprising: A first decryptor configured to receive compressed and encrypted image signals from the plurality of storage media and decrypt the compressed and encrypted encoded image signals; a first decompressor configured to receive a compression-encoded video signal from a first descrambler and to decompress said compression-coded video signal to enable display of said video program; A second decryptor configured to receive compressed encrypted encoded audio signals from the plurality of storage media and decrypt the compressed encrypted encoded audio signals; and a second decompressor configured to receive a compression-encoded audio signal from a second descrambler and to decompress said compression-encoded audio signal to selectively play a selected one of said plurality of audio programs synchronously with an associated video program an audio program for . 2. The device according to claim 1, characterized in that said decoder is arranged to decrypt and decompress encoded image and audio signals in a mutually independent non-adjacent manner. 3. The apparatus according to claim 1 or 2, characterized in that at least one of said first and second decompressors is configured to compress the encoded signal using an inverse adaptive block size discrete cosine transform compression technique to decompress. 4. Apparatus according to claim 1 or 2, characterized in that said second decompressor is arranged to decompress the compression-encoded audio program at a variable rate. 5. An apparatus according to any one of claims 1 or 2, wherein the encoded image signal forms at least one image program, and said apparatus further comprises a discriminator for combining one or more audio programs with at least one image program connect them. 6. The device according to claim 1 or 2, wherein the encoded image and audio signals are transmitted to said plurality of storage media in data packets, said decompressor further comprising a device configured to extract from said data packets A depacketizer that extracts the encoded image and audio signals. 7. The device according to claim 1 or 2, wherein said storage device is further configured to receive a device-specific key, wherein said first and second decryptors are further configured to Under the condition that the key is determined, the compressed encrypted coded image and audio signal are decrypted. 8. The device of claim 7, wherein the device-specific key is stored on a key storage medium separate from the encoded image or audio signal. 9. The device of claim 7, wherein said key storage medium is a smart card or a magnetic disk. 10. The device of claim 7, further comprising means for transmitting said device specific key. 11. The device according to claim 7, further comprising means for indicating a period of time during which said device-specific key is valid and for ensuring that said device-specific key is only used for the period of time installation. 12. The device of claim 7, wherein the device-specific key is overwritten from the key storage medium after the time interval expires. 13. Device according to claim 1 or 2, characterized in that the coded signal further comprises at least one watermark, wherein said watermark is perceived perceptually during playback of a video program or a selected audio program at a transmission rate preset as normal is not noticeable, but is noticeable when a video program or selected audio program is displayed at a rate different from the normal rate. 14. A device as claimed in claim 13, characterized in that said watermark is arranged to identify, after decompression, display time and location information relating to the encoded image signal or audio program. 15. The device of claim 1 or 2, further comprising a theater management, wherein the theater management is configured to send control signals to and receive status information from said storage device and said decoder. 16. The device according to claim 1 or 2, characterized in that the device is further configured to establish a connection, wherein the connection is configured to send and receive information from outside the device. 17. Apparatus according to claim 16, characterized in that said information comprises control and status information or updates for encoded video signals and audio programmes. 18. The device of claim 16, wherein said connection comprises a dedicated telephone data link, a dial-up telephone data link, a packet-type data link, an Internet-based link, a wireless data link or a Satellite data link. 19. The device according to claim 1 or 2, wherein said storage medium comprises at least one optical storage medium, at least one DVD disc, at least one magnetic storage medium, at least one removable hard disk, at least one hard disk serial JBOD module Or at least an internal hard drive. 20. Apparatus according to claim 1 or 2, characterized in that said storage medium comprises a plurality of storage media, and wherein the encoded image signal and the encoded audio program are non-sequentially stored on the plurality of storage media. 21. The device as claimed in claim 1 or 2, characterized in that the coded audio program is stored on a separate storage medium from the coded image signal. 22. The apparatus according to claim 1 or 2, further comprising a coded signal representing promotional information, and wherein the coded signal representing promotional information is stored differently from the coded image or audio signal or at least one coded audio program on a separate storage medium. 23. The apparatus of claim 1 or 2, further comprising a buffer synchronized with the playback of the video signal and the selected audio program. 24. Apparatus according to claim 1 or 2, characterized in that said storage means comprise means for linking different preselected parts of the encoded image signal or at least one encoded audio program with different preselected parts of the storage medium using discriminator information. 25. Apparatus according to claim 1 or 2, characterized in that said storage device further comprises means for providing parallel stripe information to enable the image signal or audio signal to be accessed at a desired data transfer rate and to provide error protection redundancy. 26. The device as claimed in claim 1 or 2, characterized in that at least two of the storage media, the decryptor and the decompressor are interconnected via at least one LAN interface. 27. The device according to claim 1 or 2, characterized in that it further comprises means for archiving and maintaining the playing history of the video program and the selected audio program. 28. The apparatus of claim 1 or 2, wherein said encoded signal further comprises an encoded signal indicative of a hint track, wherein said hint track indicates a specific portion of the program where the connection information is located. 29. The device of claim 1 or 2, further comprising a player, wherein said player is configured to distribute the encoded signals with a preselected programmable offset in time relative to each other. 30. The apparatus of claim 29, wherein said preselected programmable offset is substantially zero, whereby the encoded video signal is processed to initiate a plurality of displays of the video program at substantially the same time. 31. The apparatus of claim 1 or 2, further comprising an audio player configured to play the selected audio program synchronously with the presentation of the visual program. 32. A method in which encoded image and audio signals representing a video program and a plurality of audio programs related to said video program in compressed and encrypted form on at least one storage medium are processed to enable display of the video program, the method The steps involved are: Retrieving portions of compressed encrypted encoded image and audio signals from multiple storage media; recombining portions of said compressed encrypted encoded image and audio signals; Deciphering compressed and encrypted encoded images and audio signals to generate compressed and encoded images and audio signals; decompressing said compression encoded image and audio signals; and The image program is displayed synchronously with the selected one of the associated plurality of audio programs. 33. The method of claim 32, wherein the steps of deciphering and decompressing the encoded video signal and audio signal occur in a mutually independent non-adjacent manner. 34. The method of claim 32 or 33, wherein said step of decompressing uses an inverse adaptive block size discrete cosine transform compression technique. 35. The method of claim 32 or 33, wherein said step of decompressing is performed at a variable rate. 36. The method of claim 32 or 33, further comprising the steps of: combining encoded graphics signals to form at least one video program; and Link one or more audio programs with at least one video program. 37. The method of claim 32 or 33, wherein images and audio signals are stored on the storage medium in data packets, and said step of decompressing further comprises extracting said images and audio signals from said data packets audio signal. 38. The method according to claim 32 or 33, further comprising the step of retrieving a private key, wherein said decryption step is performed under the condition that the private key is determined. 39. The method of claim 38, wherein said private key is stored on a key storage medium separate from the image encoded signal or audio program. 40. The method of claim 38, wherein said key storage medium comprises a smart card, a magnetic storage medium or an optical storage medium. 41. The method of claim 38, wherein said private key is transmitted. 42. The method of claim 38, further comprising the step of indicating a period of time during which said private key is valid and ensuring that said private key is used only during that period of time. 43. The method of claim 38, further comprising the step of overwriting said private key from said key storage medium after the time interval expires. 44. The method according to claim 32 or 33, further comprising the step of providing at least one watermark, wherein said watermark is perceptually identifiable during playback of an image or audio program at a transmission rate preset to be normal. Unnoticeable, but perceptible when a video program or audio program is displayed at a rate other than the normal rate. 45. The method of claim 44, wherein said watermark identifies display time and location information associated with the decompressed video program or audio program after said decompressing step. 46. The method of claim 32 or 33, further comprising the step of providing a theater manager, wherein said theater manager sends and receives status and control information regarding the steps of storing, decrypting and decompressing. 47. The method of claim 32 or 33, further comprising the step of establishing a connection for sending and receiving information. 48. A method as claimed in claim 47, characterized in that said information contains status and control information or updates for encoded video programs and/or audio programs. 49. The method of claim 47, wherein said connection comprises a dedicated telephone data link, a dial-up telephone data link, a packet-type data link, an Internet-based link, a wireless data link, or a Satellite data link. 50. The method according to claim 32 or 33, wherein said storage medium comprises at least one magnetic storage medium, at least one optical storage medium, at least one removable hard disk, at least one hard disk serial JBOD module or at least one internal hard disk . 51. The method according to claim 32 or 33, wherein the storage medium comprises a plurality of magnetic storage media, and the image and audio signals are non-sequentially stored on the plurality of magnetic storage media. 52. A method as claimed in claim 32 or 33, characterized in that the audio signal is stored on a separate magnetic storage medium from the coded image signal. 53. The method according to claim 32 or 33, further comprising the step of retrieving a coded signal representing promotional information, and said coding representing promotional information is different from the coded image signal and/or the coded audio program The signals are stored on separate magnetic storage media. 54. The method of claim 32 or 33, further comprising buffering the video and audio signals to synchronize the video program with the selected audio program during playback. 55. A method as claimed in claim 32 or 33, further comprising the step of linking different preselected portions of the encoded video signal or audio signal with different preselected portions of said storage medium. 56. A method as claimed in claim 32 or 33, further comprising the step of providing parallel stripe information to enable the encoded video signal or the encoded audio program to be accessed at the desired data transmission rate and to provide error protection redundancy. 57. The method of claim 32 or 33, further comprising the step of archiving and maintaining the playback history of the encoded video program and the selected audio program. 58. A method as claimed in claim 32 or 33, further comprising the step of indicating the particular portion of the encoded video and audio signal in which the connection information is located. 59. The method of claim 32 or 33, further comprising the step of displaying said video program. 60. A method as claimed in claim 32 or 33, further comprising the step of distributing the encoded signals with a preselected programmable offset in time relative to each other. 61. The method of claim 60, wherein said preselected programmable offset is substantially zero, whereby the encoded video signal is processed to initiate multiple displays of the video program at substantially the same time.

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