Abstract: A method and mechanism for repositioning video images in a compressed data stream without requiring bit shifting. A P frame image is to be repositioned from an original position to an alternate position. The P frame image data is analyzed to determine whether the repositioning will result in the image data bit positions being changed with respect to the original image. In response to determining the bit positions will be changed, the original image data is modified by adding stuffing bits in the form of a stuffing macroblock to restore the image data to its original bit positions. The P frame is intra-coded and the stuffing macroblock is non-intra coded. A non-intra quantization matrix is selected such that upon decode the stuffing macroblock data does not adversely affect the final picture. Maintaining the original bits positions of the image data facilitates a straightforward copy of unmodified data from the original P frame to the new P frame.

Abstract: A method and mechanism for repositioning video images in a compressed data stream without requiring bit shifting. A P frame image is to be repositioned from an original position to an alternate position. The P frame image data is analyzed to determine whether the repositioning will result in the image data bit positions being changed with respect to the original image. In response to determining the bit positions will be changed, the original image data is modified by adding stuffing bits in the form of a stuffing macroblock to restore the image data to its original bit positions. The P frame is intra-coded and the stuffing macroblock is non-intra coded. A non-intra quantization matrix is selected such that upon decode the stuffing macroblock data does not adversely affect the final picture. Maintaining the original bits positions of the image data facilitates a straightforward copy of unmodified data from the original P frame to the new P frame.

Abstract: A system and method for providing a graphical user interface (GUI) in an interactive television system. In the preferred embodiment, the interactive television system comprises a video delivery system for providing video content, and at least one subscriber television including a display screen, wherein the subscriber television is coupled to the video delivery system. According to the present invention, the video delivery system provides a compressed background picture and one or more compressed insert pictures. Each of the compressed insert pictures represents a display portion of the GUI. The subscriber television receives the compressed background picture and the one or more compressed insert pictures, and operates to paste at least one of the compressed insert pictures into the compressed background picture. The pasting is preferably performed in response to interactive program execution and/or user input.

Abstract: Apparatus for developing synchronization of an intermediate layer of signal such as the transport or multiplex layer of a multi-layered compressed video signal, includes at the encoding end of the system apparatus for including a time stamp reference, such as a count value from a modulo K counter, and provision for a differential time stamp related to time stamps of a further compressed signal or differential transit times of respective transport packets. Flags are included in transport packets of signal to indicate the presence or absence of the time stamps or differential time stamps. At the receiving end of the system, circuitry examines respective packets for the condition of the flags to locate specific information such as the time stamps and differential time stamps. A counter is responsive to a controlled receiver clock signal and the count value of this counter is sampled at the arrival of transport packets including a flag indicating the presence of a time stamp.

Abstract: Apparatus for developing synchronization of an intermediate layer of signal such as the transport or multiplex layer of a multi-layered compressed video signal, includes at the encoding end of the system apparatus for including a time stamp reference, such as a count value from a modulo K counter, and provision for a differential time stamp which may be updated by the transit times of respective (e.g., multiplexing) circuits as the signal transits such circuits. At the receiving end of the system a counter is responsive to a controlled receiver clock signal and the count value of this counter is sampled at the arrival of the time stamps embedded in the transport layer. The time stamps and the differential time stamps are retrieved from the signal and combined to form a corrected time stamp. The differences of successive sampled count values of the receiver counter are compared with the differences of corresponding successive corrected time stamps to provide a signal to control the receiver clock signal.

Abstract: Apparatus for developing synchronization of an intermediate layer of signal such as the transport or multiplex layer of a multi-layered compressed video signal, includes at the encoding end of the system apparatus for including a time stamp reference, such as a count value from a modulo K counter, and provision for a differential time stamp which may be updated by the transit times of respective (e.g., multiplexing) circuits as the to signal transits such circuits. At the receiving end of the system a counter is responsive to a controlled receiver clock signal and the count value of this counter is sampled at the arrival of the time stamps embedded in the transport layer. The time stamps and the differential time stamps are retrieved from the signal and combined to form a corrected time stamp. The differences of successive sampled count values of the receiver counter are compared with the differences of corresponding successive corrected time stamps to provide a signal to control the receiver clock signal.

Abstract: A digital video signal processing system includes apparatus for concealing errors which might occur in reproduced images due to image data lost during signal transmission. The system includes circuitry for detecting transmitted video data, generating error signals if errors are present in segments (transport blocks) of the received data, and excising segments having errors from the data stream. The received data is applied to a decoder/decompressor system which decodes and decompresses the transmitted video data according to a predetermined sequence and applies the decompressed video data to a memory (for subsequent display or recording, etc.). The decompressor is responsive to the error signals for altering the predetermined sequence.

Abstract: A video signal compression system includes motion compensated predictive compression apparatus for compressing respective frames of video signal according to either intraframe processing or interframe processing on a block by block basis to generate blocks of compressed data and associated motion vectors. A compressed signal formatter arranges the blocks of compressed data and the associated motion vectors according to a desired signal protocol wherein motion vectors of interframe processed frames are associated with corresponding blocks of compressed data and motion vectors of intraframe processed frames are associated with blocks substantially adjacent to corresponding blocks of compressed data. The motion vectors are included with intraframe compressed data to facilitate error concealment at respective receiver apparatus.

Abstract: A compression/decompression system includes a source of non-interlaced scanned video signal. A preprocessor constructs interlaced scanned video signal from the non-interlaced scanned video signal by selection of alternate lines of successive non-interlaced image signals. The interlaced scanned video signal is compressed according to known methods to generate primary compressed video data. The primary data is decompressed by known processes, inverse to the compression processes, to regenerate the interlaced scanned frames. Interlaced scanned video signal, corresponding to the intervening lines of the non-interlaced scanned video signal, which were not included in the primary interlaced scanned video signal, is predicted from the decompressed frames of video signal. In addition the intervening lines of the original non-interlaced scanned video signal, which were not included in the primary interlaced scanned video signal, are formed into secondary interlaced scanned video signal.

Abstract: Elements of the compressed video signal which are of greatest importance to signal decompression are set a plurality of times in redundant transport cells. Media error codes are concatenated to the redundant data such that when and if such redundant data is applied to the corresponding decompressor, the media error code will automatically force the decompressor to resynchronize.

Abstract: A digital compressed video signal transmission system includes a transport processor for segmenting compressed MPEG video data into transport cells for transmission. Prior to formation of the transport cells, at least a portion of the 32-bit MPEG slice start codes are excised from the compressed data. An entry pointer is generated to indicate the location of the beginning of a slice, which pointer is included in a transport cell header. In a corresponding receiver, the transport header is examined for a slice entry pointer, and if one is found, a slice start code is inserted in the transport payload data stream at the location indicated by the pointer so as to provide a signal according to the MPEG protocol.

Abstract: A digital compressed video signal transmission system includes a transport processor for segmenting compressed data into transport cells for transmission. Particular portions of the compressed data are formatted into further transport cells, which further transport cells are interspersed with normally occurring transport cells. The further transport cells include redundant video signal data which may be utilized to resynchronize a compressed video signal decoder after loss or corruption of transmitted data.

Abstract: A processing system requiring adaptive selection of ones of a family of transfer functions is implemented with a single transfer function element arranged to perform a transfer function representative of the family of functions. Respective ones of the family of transfer functions are realized by selectively offsetting signal applied to the transfer function element, and selectively offsetting and scaling signal provided by the transfer function element.

Abstract: Image reproduction is improved in an MPEG-like television receiver by inclusion of post-processing adaptive error concealment. Compressed video signal is examined to determine blocks of video signal containing errors, and error tokens are generated for identifying corresponding blocks of decompressed pixel values. Pixel values adjacent the decompressed blocks of pixel values containing errors are examined to generate estimates of the relative image motion and image detail in the area of such blocks. The block of pixel values is replaced with temporally displaced co-located blocks of pixel values or interpolated data depending upon whether the estimate of image motion is lesser or greater than the estimate of image detail.

Abstract: Apparatus for decoding an HDTV signal conveyed as high and low priority data in high and low priority channels respectively, wherein said high and low priority data originated from blocks of hierarchically encoded compressed video data, with data of greater importance for image reproduction from each block allocated to the high priority channel and the remaining data from each block allocated to the low priority channel, includes circuitry for identifying and segmenting high and low priority data for corresponding blocks and recombining the high and low priority data into an hierarchically encoded compressed video data stream.

Abstract: Apparatus for encoding/decoding a HDTV signal for e.g., terrestrial transmission includes a compression circuit responsive to high definition video source signals for providing ierarchically layered codewords CW representing compressed video data and associated codewords T, defining the types of data represented by the codewords CW. A priority selection circuit, responsive to the codewords CW and T, parses the codewords CW into high and low priority codeword sequences wherein the high and low priority codeword sequences correspond to compressed video data of relatively greater and lesser importance to image reproduction respectively. A transport processor, responsive to the high and low priority codeword sequences, forms high and low priority transport blocks of high and low priority codewords respectively. Each transport block includes a header, codewords CW and error detection check bits. The respective transport blocks are applied to an forward error check circuit for applying additional error check data.

Abstract: Apparatus for encoding/decoding a HDTV signal for e.g. terrestrial transmission includes a priority selection processor for parsing compressed video codewords between high and low priority channels for transmission. A compression circuit responsive to high definition video source signals provides hierarchically layered codewords CW representing compressed video data and associated codewords T. defining the types of data represented by the codewords CW. The priority selection processor, responsive to the codewords CW and T, counts the number of bits in predetermined blocks of data and determines the number of bits in each block to be allocated to the respective channels. Thereafter the processor parses the codewords CW into high and low priority codeword sequences wherein the high and low priority codeword sequences correspond to compressed video data of relatively greater and lesser importance to image reproduction respectively.

Abstract: A moving-image signal encoding apparatus includes a transmission buffer memory. A first quantization step size for a normal block other than a refreshed block is determined on the basis of an occupied capacity of the buffer memory. A second quantization step size for the refreshed block is determined on the basis of the first quantization step size. A refreshment instruction signal is generated. One of the first quantization step size and the second quantization step size is selected in response to the refreshment instruction signal.

Abstract: A video signal transmission system includes adaptive compansion circuitry to improve the signal-to-noise ratio of transmitted signals. A compandor at the transmitter, and corresponding inverse compandor at the receiver, are arranged to have a plurality of selectable compansion transfer characteristics. Selection of particular ones of the transfer characteristics is responsive to, e.g., predicted values of current signal.

Abstract: A moving-image signal encoding apparatus includes a transmission buffer memory. A first quantization step size for a normal block other than a refreshed block is determined on the basis of an occupied capacity of the buffer memory. A second quantization step size for the refreshed block is determined on the basis of the first quantization step size. A refreshment instruction signal is generated. One of the first quantization step size and the second quantization step size is selected in response to the refreshment instruction signal.