Abstract: The present invention relates to broadcasting/multicasting of media content over a communication network using shared bandwidth available from peer-to-peer networking. The system of the present invention includes a plurality of broadcast devices, a plurality of receiving devices, a plurality of databases, and a control center. The control center is the central nerve of the network, and provides a number of services, including but not limited to channel control, ad insertion, conditional access, program guide services, and the like. The broadcast device converts media content, which can be television, radio, and other data, received from various content providers, into digital data packets, having a suitable format for transmission over the Internet. Each receiving device will request the relevant packets, decode the received packets, and display or present the media content contained in the packets via an associated device.

Abstract: Methods and devices for creating an anisotropic strain in a semiconductor quantum well structure to induce anisotropy thereof are disclosed herein. Initially, a substrate is provided, and a quantum well structure formed upon the substrate. A first crystalline layer (e.g., a GaAs layer) having a first crystalline phase can then be deposited upon the quantum well structure. Thereafter, a second crystalline layer (e.g., a GaN layer) having a second crystalline phase and a thickness thereof can be formed upon the first crystalline layer to thereby induce an anisotropic strain in the quantum well structure to produce a quantum well device thereof. Additionally, the second crystalline layer (e.g., GaN) can be formed from a transparent material and utilized as an anti-reflection layer. By properly choosing the thickness of the second crystalline layer (e.g., a GaN layer), a desired anisotropic strain as well as a desired anti-reflection wavelength can be achieved.

Abstract: The present invention provides systems and methods for automating the conversion of digital images from a first storage media used by digital cameras to a second storage media used by computers and video playback devices. The conversion can be performed by a self-contained kiosk which detects the insertion of the first storage media containing the images in a first format. A processor at the kiosk converts the images into a second format (e.g., one that is compatible with video playback devices such as a DVD player). The images may then be copied to and stored on a second storage media in both the first (original) format and the second format. The second storage media is then dispensed from the kiosk. The resulting second storage media is compatible with video playback devices and serves as a master negative.

Abstract: A terahertz electromagnetic energy detector comprises a (100) oriented multiple quantum well thermally bonded to a first transparent substrate having a direction dependent thermal coefficient of expansion such that this coefficient matches the thermal coefficient of expansion of MQW in one direction but different form the direction-dependent thermal coefficient of expansion of the MQW in a perpendicular direction. The resultant internal thermally induced anisotropic strain leads to a polarization dependence of the optical absorption that is strongest near the lowest heavy-hole and light-hole exciton peaks. A second transparent substrate is placed beneath the first transparent substrate and is oriented so that its thermal coefficients of expansion act in a direction perpendicular to those of the first transparent substrate so that the accumulated phase retardation of the optical wave associated with birefringence of the substrate is effectively cancelled.

Abstract: An apparatus for providing VCR-like “trick mode” functions, such as pause, fast-forward, and rewind, in a distributed, video-on-demand program environment. Trick modes are supported by locally altering the viewing speed for each user who requests such functions, without affecting the operation of the central data source in any way. Thus, a virtual unlimited number of viewers are able to enjoy random access to video programming, including virtually continuous trick mode functionality. This is accomplished in a manner that is operable with existing telephone and cable distribution infrastructure.

Abstract: A compressed video playback system which eliminates playback mode transition artifacts. Transitions between various playback modes are effected in such a manner that transition artifacts are eliminated by delaying playback mode transitions until appropriate frames of data are detected for propagation to the compressed video decoder. In addition, compressed video data retrieval methods are improved for supporting multi-speed playback modes in both forward and reverse directions in an optimal manner.

Abstract: A compressed video decoder/encoder (reencoder) system for varying the compression ratio of a compressed video program. The composite reencoder system implements tightly coupled elements for decoding and encoding compressed video data implementing techniques of header forwarding and utilizing an architecture in which a shared motion compensator supports both decoding and encoding operations simultaneously. The reencoder system may be introduced in a statistical multiplexer for generating a compressed video data stream multiplex suitable for use in cable distribution and other video distribution systems.

Abstract: An digital home video system providing recording and playback of compressed video programs using an archival storage medium; simultaneous recording and playback using the same archival medium; storage of multiple programs on a single videotape; a full array of trick mode functions; efficient management of the contents of a video tape or other archival storage medium; and real-time random access to video program content, enabling truly interactive playback. These capabilities are provided by combining the best features of an archival storage medium such as digital video tape: namely, potentially large storage capacity, but low tolerance for variable data rate, and essentially linear program access; with the complementary features of a relatively high-access storage device such as a fixed disk drive: namely, tolerance for a highly variable data rate, and random access capability, but relatively lower storage capacity.

Abstract: A system for providing efficient constant bit rate distribution of variable bit-rate encoded video programs while facilitating the distribution of encoded video programs, along with Auxiliary Data of a general character, to one or more receivers. At a particular receiver, a customized augmented video program is created by inserting selected portions of the Auxiliary Data into a selected encoded video program. The encoded video portion of the augmented video program can be transmitted, decoded and displayed in real time, while the Auxiliary Data need not be transmitted in real time but can be stored locally at the receiver for real-time presentation at a later time. Real time presentation might include insertion into the video program while non real-time presentation might include insertion into non-video applications separate from the video program.

Abstract: A method for increasing channel utilization for a data channel transmitting a multiplex of a set of one or more encoded program streams, each program stream in being decodeable by a corresponding decoder, each corresponding decoder including a corresponding decoder buffer, the decoder buffers having a maximum allowable size, the method comprising selecting encoded pictures to be modified, said selecting according to a criterion which includes preventing any underflow of any decoder buffer, modifying each said selected encoded picture to form a corresponding modified encoded picture, said modified encoded picture having less data than said selected encoded picture, and transmitting the corresponding modified encoded pictures through the channel in place of the selected encoded pictures.

Abstract: A compressed video playback system which eliminates playback mode transition artifacts. Transitions between various playback modes are effected in such a manner that transition artifacts are eliminated by delaying playback mode transitions until appropriate frames of data are detected for propagation to the compressed video decoder. In addition, compressed video data retrieval methods are improved for supporting multi-speed playback modes in both forward and reverse directions in an optimal manner.

Abstract: Selective video-on-demand access is provided to a virtually unlimited number of subscribers by partitioning the video program into an ordered sequence of N segments and providing the subscribers concurrent access to each of the N segments. A data stream representative of the video program is partitioned into N subsequences, each representative of one of the N segments. The data of each of the N subsequences is organized as an ordered sequence of elements. The elements of each of the N subsequences are interleaved and the interleaved data stream is continuously transmitted over a video program distribution medium at a rate which renders the data representing each segment concurrently available to any subscriber having a receiver capable of selecting, assembling, and displaying the data of a particular segment.

Abstract: A method and apparatus for reducing the size of data rate fluctuations that occur in forming a multiplex of a set of program streams, each program stream in said set being decodeable by a corresponding decoder, each corresponding decoder including a corresponding decoder buffer, said decoder buffers having a maximum allowable size, said method comprising varying the formation of the different program streams in said set to minimize the memory requirement of the decoder buffers. In one embodiment, for the case of the streams being segments of a program, varying includes varying the segment length. In another embodiment, varying includes adjusting the relative alignment of the program streams. Different embodiments of adjusting include inserting program material such as a pause at selected points in time, causing decoder buffers to underflow at selected points in time, and varying the rate of decoding and display at selected points in time.

Abstract: A method and apparatus multiplexing several encoded program streams into a single multiplex suitable for transmission over a data channel, the streams typically including video and audio. According to one embodiment of the invention, high data channel utilization is achieved by determining the order of sending data packets of program streams into the data channel. According to this embodiment, whenever data is to be sent into the data channel, a determination is made of which packet to send or append to the multiplex, said determination by selecting a channel that has a decoder buffer that is not approaching a full state, and said next packet is appended to said multiplex. The method further includes selecting a channel that substantially balances the decoder buffers of the decoders with which the program streams are decodeable.

Abstract: Virtually random and on-demand access is provided to a virtually unlimited number of subscribers by partitioning the video program into an ordered sequence of n segments and providing the subscribers concurrent access to each of the n subsequences. A data stream representative of the video program is partitioned into n subsequences, each representative of one of the n segments. The data of each of the n subsequences is organized as an ordered sequence of elements. The elements of each of the n subsequences are interleaved and the interleaved data stream is continuously transmitted over a video program distribution medium at a rate which renders the data representing each segment concurrently available to any subscriber having a receiver capable of selecting, assembling, and displaying the data of a particular segment. The data stream can be compressed prior to interleaving using one of many known video data compression standards and techniques.

Abstract: A method and apparatus are provided for decoding variable length codewords carried in data blocks. A first buffer is loaded with a succession of data blocks. A second buffer is loaded with a first data block from the first buffer during a decoding cycle. The variable length codewords from the first data block in the second buffer are decoded to recover information. The process continues, with the second buffer being loaded with one data block at a time to successively decode new data blocks during successive decoding cycles.

Abstract: A multiple serial access memory which includes a dynamic random access memory array is disclosed. The array is randomly addressed to input blocks of data. Address signals are provided to the array to output rows of data. A plurality of serial output ports are coupled to the output of the array for selectively latching different rows of data output from the array. The serial output ports are clocked to output the latched data therefrom. In an illustrated embodiment, each of the serial output ports contains a shift register having a length equal to the width of the memory array. The shift register is responsive to a first timing signal for latching a row of data from the array. A second timing signal actuates the shift register to shift a row of latched data. The serial access selector coupled to the shift register outputs a selected portion of the shifted data from the serial output port.

Abstract: A macroblock packet format is provided for use in a digital HDTV system wherein successive video frames are divided into a plurality of macroblocks. The macroblocks comprise a plurality of superblocks, each containing a plurality of luminance and chrominance video data blocks. A DLEN field is provided in the macroblock packet format to identify the length of the macroblock packet. The packets also include variable length encoded portions of video data. The macroblock packets are transmitted in a data multiplex that also includes a next macroblock position (NMP) word. A receiver compares the DLEN information with the NMP word to verify synchronization, and reacquires the signal if synchronization has been lost.

Abstract: Apparatus is provided for decoding variable length code words to recover transform coefficients, such as DCT transform coefficients provided by a high definition television encoder. A first category of the code words has a length of no more than n bits. A second category has a length of greater than n bits. A feedback ROM is used to decode the code words. Code words from the first category are processed by directly addressing a lookup table in the ROM. Code words from the second category are processed using multiple passes through the ROM, wherein a portion of the data output during a prior pass is fed back to address the memory during a subsequent pass.

Abstract: A multichannel image compression system uses a plurality of encoders to compress image data. A coding level command is provided to each of the encoders to specify a level of quality to be provided by each encoder. Encoded image data, provided by the encoders in response to the coding level command, is multiplexed into a combined signal for transmission. The coding level command is adjusted in response to an accumulated amount of data from the combined signal, to maintain the accumulated data within a throughput capability of a communication channel. Although the coding level command may specify a global coding level that is the same for all of the encoders, the encoders can derive local coding levels from the global coding level to provide different encoding qualities. Decoder apparatus is provided to recover an image from the compressed image data.