Abstract: A diversity transmission scheme uses a number of antennas that is greater than the limitation of two transmitting antennas in the well-known Alamouti scheme. In an embodiment comprising four antennas, the antennas transmit in pairs such that each antenna transmits a block that is used in the Alamouti scheme. This increases the transmission rate. For example, the transmission of two signals at a given time slot increases transmission rate by a factor of two. The invention not only increases the number of antennas, but also increases the transmission rate. At the receiver end, the code is decoded without matrix inversion and without much noise enhancement. Moreover, noise enhancement stability is increased by a simple, partial interference cancellation scheme, that results in improved decoding performance.

Abstract: Some demonstrative embodiments of the invention include devices, systems and/or methods of error-protection of a wireless video transmission. Some demonstrative embodiments of the invention include a wireless transmitter to transmit a wireless transmission including a data stream corresponding to at least a video signal. The data stream may include a plurality of data components, which are protected according to an unequal error protection scheme. At least first and second data components of the plurality of data components may be protected by first and second error protection mechanisms, respectively. Other embodiments are described and claimed.

Abstract: Wireless transmission of high-definition video, whether essentially uncompressed or compressed, is prone to errors during reception due to the condition of the wireless link. To ensure video quality during changing link conditions it is desirable to ensure that those portions of the video that represent the more important components of the video signal, such as the lower special frequencies or most significant bits, are assured correct reception at the receiver. Bandwidth limitations of the wireless link affect the amount of data that can be sent over the link. Hence, using a high level error recovery for all of the information is not feasible. Accordingly, a method and apparatus for unequal error protection is disclosed that provides a higher level of error protection to the more important elements of the transmission while affording less error protection to the other elements of the transmission.

Abstract: The uncompressed wireless transmission of video, as with many other wireless applications, requires constant knowledge of channel characteristics at the receiver end. To estimate the channel and track its changes, pilots containing known data are sent in various parts of the used bandwidth. The use of such pilots reduces the effective bandwidth available for data transmission. Due to the relative high immunity to introduced interference of certain transmission modes, such as QPSK and QAM, pilots can be modulated by digital data components. At the receiver, pilots are demodulated and used for a decision-directed circuit to determine the characteristics of the transmission channel. The additional bandwidth allows a higher data rate which may be such used for various purposes as diversity, coding, etc. Such use of pilot signals is of particular advantage in the wireless transmission of the DC and near DC components of essentially uncompressed video.

Abstract: The vertical blanking period is an idle period in video transmission that was originally intended for allowing the trace back of an electron beam to its point of origin. When sending the video signal over a wireless channel, the wireless channel may remain free of transmission of data during this period. However, in wireless transmission of a video signal in general, and in the transmission of an essentially uncompressed video signal in particular, there is a need to use all the bandwidth available, especially when transmitting a high-definition video signal. Therefore, a method is taught for using the vertical blanking period of a video signal for modem maintenance.

Abstract: The invention enables the transmission of continuous complex numbers using a symbol based transmission scheme such as OFDM. Accordingly, complex numbers are mapped to the constellation map, enabling a fine granularity of constellation points. This scheme may be used, for example, in the transmission of video where the coefficients representing the higher frequency of each of the video components, as well as the quantization error values of the DC and near DC components, or some, possibly non-linear transformation thereof, are sent as pairs of real and imaginary portions of a complex number that comprises a symbol.

Abstract: An apparatus and method for wireless transmission of uncompressed HDTV video overcomes the challenges of sending vast amounts of information over a wireless link. This is achieved by direct mapping of transformation coefficients of the video components to communication symbols, such as OFDM symbols. A main portion of the important transform coefficients, for example the MSBs of the coefficients representing lower frequencies of each of the video components, and in particular the quantized values of the lower frequencies components, are sent in a coarse representation using, for example, QPSK or QAM. The coefficients representing higher frequencies of the video components, and the quantization error values of the lower frequencies components, or some, non-linear transformation thereof, are sent as pairs of real and imaginary portions of a complex number that comprises a point in a fine constellation. The invention further provides a delay-less and buffer-less implementation of transmitter and receiver pairs.

Abstract: A method of generating a compressed video stream, comprising: providing a plurality of display commands which represents a display; generating a plurality of quantized transform coefficients from said display commands, wherein said quantization is different for different display commands; and creating a compressed video stream utilizing said coefficients.

Abstract: A method of generating a compressed video stream, comprising: providing a plurality of display commands which represents a display; generating a plurality of quantized transform coefficients from said display commands, wherein said quantization is different for different display commands; and creating a compressed video stream utilization said coefficients.

Abstract: A computer may be remotely accessed. At a first location, display commands are generated. The display commands are covered into a compressed video data stream. Each display element (5) is checked if it is encoded (52). If object is encoded, it is transcribed into MPEG (54). The image is adjusted for display (56) and compression (58). Additional steps of motion determination (60), change detection (62), compression depth and frame determination (66, 68) are executed. Then the data is transmitted to a second location. The display commands are decompressed and displayed as an image at the second location.

Abstract: A computer may be remotely accessed. At a first location, display commands are generated. The display commands are covered into a compressed video data stream. Each display element (5) is checked if it is encoded (52). If object is encoded, it is transcribed into MPEG (54). The image is adjusted for display (56) and compression (58). Additional steps of motion determination (60), change detection (62), compression depth and frame determination (66, 68) are executed. Then the data is transmitted to a second location. The display commands are decompressed and displayed as an image at the second location.

Abstract: A Simple Inter Color Lossless Image Coder (SICLIC) for the compression of colored images is provided. The color image is treated as several interlaced gray level images that correspond to respective distinct color planes. The compression scenario utilizes three main steps, such as selection of the predictor, context forming with bias cancellation and coding. SICLIC implements predictors, context forming and encoder techniques that exploit the intra- and inter-color plane correlations in an effective and relatively computationally inexpensive manner. The predictor is selected on the basis of the right selection of the contribution of each color plane between the intra- and inter-plane predictors obtained as a weight average of contribution from different color planes. SICLIC processes the image in two modes—regular mode and run mode. A special care is taken to ensure a proper treatment of joint runs, which occur simultaneously in all color planes.

Abstract: A method of transmitting an image over a compressed video transport, as part of an image stream, comprising determining at least one quality for at least a part of an image based on a rate of change of said part; and transmitting said image part at said quality using said transport. Optionally, the image is static. Optionally, an improvement of the image is transmitted after a time.

Abstract: A multipoint control unit (MCU) or other digital video-processing apparatus operates to manipulate compressed digital video from several compressed digital video sources. The apparatus has a plurality of video input modules and a plurality of video output module. Each of the video input modules receives a compressed video signal from one of the sources and generally decodes the data into a primary data stream and a secondary data stream. The video output module receives the primary and secondary data streams, from at least one of the input module for generally encoding to a compressed output stream for transmission.

Abstract: A computer may be remotely accessed. At a first location, display commands are generated. The display commands are covered into a compressed video data stream. Each display element (5) is checked if it is encoded (52). If object is encoded, it is transcribed into MPEG (54). The image is adjusted for display (56) and compression (58). Additional steps of motion determination (60), change detection (62), compression depth and frame determination (66, 68) are executed. Then the data is transmitted to a second location. The display commands are decompressed and displayed as an image at the second location.

Abstract: A multipoint control unit (MCU) or other digital video-processing apparatus operates to manipulate compressed digital video from several compressed digital video sources. The apparatus has a plurality of video input modules and a plurality of video output module. Each of the video input modules receives a compressed video signal from one of the sources and generally decodes the data into a primary data stream and a secondary data stream. The video output module receives the primary and secondary data streams, from at least one of the input module for generally encoding to a compressed output stream for transmission.

Abstract: A multipoint control unit (MCU) for facilitating communication between a plurality of endpoints. Each endpoint sends a compressed video signal and receives a compressed video signal. The MCU has a plurality of video input modules and a video output module. Each of the video input modules receives a video signal from one of the endpoints and generally decodes the data into a primary data stream and a secondary data stream. The video output module includes a rate control unit and a generalized encoder that receive the primary and secondary data streams for generally encoding to a compressed output stream for transmission to an endpoint.

Abstract: A computer may be remotely accessed. At a first location, display commands are generated. The display commands are covered into a compressed video data stream. Each display element (5) is checked if it is encoded (52). If object is encoded, it is transcribed into MPEG (54). The image is adjusted for display (56) and compression (58). Additional steps of motion determination (60), change detection (62), compression depth and frame determination (66, 68) are executed. Then the data is transmitted to a second location. The display commands are decompressed and displayed as an image at the second location.

Abstract: A computer may be remotely accessed. At a first location, display commands are generated. The display commands are covered into a compressed video data stream. Each display element (5) is checked if it is encoded (52). If object is encoded, it is transcribed into MPEG (54). The image is adjusted for display (56) and compression (58). Additional steps of motion determination (60), change detection (62), compression depth and frame determination (66, 68) are executed. Then the data is transmitted to a second location. The display commands are decompressed and displayed as an image at the second location.

Abstract: A method for performing an efficient inverse Discrete Fourier Transform (iDCT) is described. Single Instruction Multiple Data (SIMD) instructions are performed concurrently on a plurality of fixed-point data stored in multimedia registers. Operations on fixed-point data can be performed more quickly than corresponding floating-point operations. Throughout the processing of the iDCT, the fixed-point data are carefully shifted to retain the most significant bits and thereby preserve the accuracy of the mulitmedia operations. The iDCT step of transposing the matrix of multimedia data is accomplished while the data is collected to further improve efficiency. Moreover, the step of transposing the matrix of data is broken down into a series of smaller transpositions, depending on the amount of data which the processor can operate on at the same time.