Abstract: A method and apparatus are disclosed for operating a transport stream encoder to produce a stream of packets carrying data representing a plurality of component signals which comprises the following steps. The packet stream is partitioned into successive groups, each group containing a predetermined number of packet slots. A plurality of priority lists is maintained, one for each of the packet slots in the group. Each priority list contains a plurality of entries, and each entry identifies one of the component signals. When a packet slot is to be produced, the entries in the priority list corresponding to that packet slot are traversed, one at a time. For each of those entries it is determined whether the component signal identified by that entry can produce a packet. If it can, a packet containing data representing that component signal is produced. Only if none of the component signals identified by the entries in the priority list can produce a packet is a null packet produced.

Abstract: A system for interconnecting audio, video and data signals available in compressed form includes a bus having a plurality of channels for transmitting signal. A bus interface is located at respective signal processing devices, which interface includes a decoder to control the respective interface responsive to control signal transmitted in one of the channels. Data is transmitted in the channels in a superpacket structure. Processing devices which generate signal to be applied to the bus, such as a receiver which provides MPEG transport packets, include apparatus to form such superpackets. Respective superpackets include at least a transport packet and a timestamp related to the timing of occurrence of the transport packet. The transport packet and timestamp are located in predetermined positions within respective superpackets.

Abstract: A method for asynchronously maintaining an image on a display device comprises the following steps. First, a drawing request is received from the application program. Then a drawing area of the image is determined in response to the received drawing request and an entry representing the drawing area is inserted into a list of entries representing respective drawing areas. A screen update request is then received from the application program. In response to this received screen update request, an entry representing a drawing area is retrieved from the list, and graphic objects are redrawn if any portion of the graphic object lies within the drawing area represented by the retrieved entry.

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: A television signal receiving system includes a deinterleaving network (18) containing first and second deinterleaving functions associated with respective memory address controllers (20, 25). One or the other of the deinterleaving functions is selected for use by a multiplexer (30) in response to a Deinterleaver Select control signal. Deinterleaving is accomplished by controlling the read/write addressing of a memory (35) by the selected deinterleaving function.

Abstract: In an audio video interactive (AVI) receiver receiving a packet stream including a directory and an AVI program having an associated identifier in the directory, a method is disclosed for controlling the execution of the AVI program comprises the following steps. First, loading the AVI program into a memory in response to the presence of the AVI program in the packet stream. Then beginning execution of the loaded AVI program. And then minimizing the executing AVI program when a directory identifying a different AVI program is detected in the packet stream.

Abstract: In a video signal processor including a motion compensated predictive coding data compression system, three adjacent image frames (1, 2, 3) are analyzed to detect a luminance gradient such as is typically associated with image fading. The frames are similarly divided into several segments (A . . . L). The sum of the absolute pixel value differences between corresponding segments from adjacent frames is obtained for each of two pairs adjacent frame segments (DIFF.sub.1-2 ; DIFF.sub.2-3). The ratio of the two frame differences (S) is obtained for each segment. Fading is indicated if the ratio remains substantially constant for all or a predetermined number of regions. If fading is detected, any motion vectors generated by the motion coder are assigned a zero value and are not coded.

Abstract: A sample rate converter includes a first interpolator which generates samples intermediate samples provided at a first sample rate. A second interpolator, using the intermediate samples, generates further samples at a second sample rate which are intermediate the intermediate samples. An accumulator which accumulates a value representing the ratio of the first and second sample rates, generates scale factors for performing the interpolations, and a clock signal at the second sample rate.

Abstract: A digital signal proces sing system for receiving and processing a high definition television signal, eg., in a Pulse Amplitude Modulation (PAM) format, includes a filter for rejecting interferer signals such as a narrowband continuous wave NTSC co-channel interferer. In an illustrated embodiment the rejection filter is a digital FIR filter (18) located after a (de)rotator (16) in a carrier recovery network (16, 20, 24, 26, 28). The filter exhibits a zero throughput delay bandpass response with attenuation notches for rejecting NTSC co-channel picture and chrominance baseband carrier frequencies.

Abstract: In an optical recording apparatus light is directed to and reflected from a recording medium to recover recorded information. The intensity of direct and reflected light is measured and the ratio of the measured values is used to control the intensity of the light source to maintain the intensity of reflected light substantially constant.

Abstract: Apparatus and a method for formatting executable codes and data, defining interactive applications, with video and audio program material, for reliable and convenient access includes compressing (18, 21) audio and video programs according to a protocol such as MPEG. The compressed audio and video (A/V) programs are segmented (19, 22) into transport packets, with audio transport packets identified by a first service identifier SCID.sub.Ai, and video transport packets identified by a second service identifier, SCID.sub.Vi. Interactive application programs associated with A/V programs are compiled (10) into functional modules and condensed. A module may be executable software or data. A module includes code/data and a header. The code/data portion of each module undergoes cyclic redundancy coding (CRC) over the entire module and CRC check bits are concatenated or appended to the module. Respective modules are segmented (14) into transport packets.

Abstract: A satellite video receiver (12) for providing output signals to a television signal receiver (52) includes apparatus (10, 15, 16, 20, 45, 60, 65, 70) for operator selection of the modulator output channel frequency of the satellite receiver. The operator may select a modulator main channel, or an alternative manufacturer pre-set modulator default channel. In a first recovery mode, the operator may automatically replace an existing modulator channel with a manufacturer pre-set default channel, e.g., if a chosen main channel is forgotten. In another recovery mode, the operator may automatically re-establish a previously selected modulator main channel recalled from memory.

Abstract: A method is disclosed for processing modules in an audio video interactive (AVI) receiver receiving a packet service including a plurality of modules, each module having a name and including time multiplexed transmission units, each transmission unit including a header packet containing the name of the module. First a request to perform a process on a module identified by a name is received and an entry containing the received name and requested process is inserted into a list of entries. A header packet in the packet service is then detected. If the name in the detected header packet matches a name in an entry in the list, packet processing circuitry performs the process in the matching entry and a message is sent indicating that the process has been performed.

Abstract: An adaptive scan format converter (14, FIG. 1; FIG. 2) at a transmitter/encoder of a video signal processing system such as a high definition television (HDTV) system, as a function of what format is desired for coding and transmission via an output channel. Similarly, at a receiver, a received scan format is automatically converted (36, FIG. 1; FIG. 2) to a desired format for display as needed. For example, a received interlaced signal (I) will be automatically converted to progressive (P) format to be compatible with a progressive scan display device (39). A received progressive signal will be passed to the display device without format conversion. Automatic scan conversion is performed seamlessly so that, for example, the conversion between progressive main television program material and interlaced commercial material is produced without artifacts and is essentially invisible to a viewer.

Abstract: A blind multipath equalizer for a digital communication channel is disclosed. The equalizer includes a sparse digital filter, responsive to a source of a received signal including a digital data signal, and including a plurality of taps, each responsive to a tap coefficient and time displacement, which produces a multipath corrected digital output signal. A filter controller is responsive to the received signal for detecting a multipath signal by calculating the autocorrelation of the received signal, detecting a multipath signal based on the autocorrelation and supplying a tap coefficient and time displacement to one of the plurality of taps to cancel the detected multipath signal.

Abstract: In an MPEG multi-channel audio signal processor, a decoder requires a respective decoder matrix for determining different output channels from coded audio data. Some transmitted information indicates basic parameters of the multi-channel system. This information may be used to address a currently required decoder matrix which is stored in a decoder memory. The storage of a large number of such matrices would be required to enable the decoder to decode all possible channel configurations. Instead of addressing a required decoder matrix stored in decoder memory, initially the current encoder matrix is reconstructed in the decoder using the related transmitted information. The required decoder matrix is then computed from the reconstructed encoder matrix using a matrix inversion technique.

Abstract: An inverse transport processor system for a TDM packet signal TV receiver includes apparatus for selectively extracting desired payloads of program component data and coupling this data to a common buffer memory data input port. A microprocessor associated with the system also couples data to the common buffer memory data input port. The respective component payloads and data generated by the microprocessor are stored in respective blocks of the common buffer memory in response to associated memory address which are applied to a memory address input port by an address multiplexer. A decryption device is included to decrypt payload data according to packet specific decryption keys. In addition a detector is included to detect payloads including entitlement data. Payloads containing entitlement data are directed via the common buffer memory to a smart card which generates the packet specific decryption keys.

Abstract: A blind equalization process (200) for an adaptive equalizer including a plurality of taps, each having a corresponding coefficient, is disclosed which comprises the following steps. Blind equalization (204) is performed on a subset of the coefficients in the adaptive equalizer. Then, if the coefficients have converged (206), a decision directed adaptive equalization process (220) is initiated.

Abstract: In a packet audio/video signal transmission system, program guide information is formed as a master guide and a special guide. The master guide contains programming information for the period of the current several hours. The special guide contains programming information for the next thirty days, for example. The master guide is sent as a service on each carrier or transponder to render it readily available regardless of the carrier frequency to which the receiver is tuned. The special guide is transmitted on only one of the carriers (transponders) to minimize use of system bandwidth.

Abstract: A video signal compressor includes apparatus for generating motion vectors for respective blocks of video data. Motion vectors, other than those which provide direction to co-located blocks in other frames, are determined to be candidates for conversion to vectors which do provide direction to co-located blocks. However, conversion is precluded if the vector is determined to be correlated with one of the neighboring motion vectors.