Abstract: An inverse discrete cosine transform processor for transforming a video signal from frequency domain signals into spatial domain signals. A bus converter receives DCT coefficient data from parallel processing paths and converts the DCT coefficient data to even and odd processing paths. Partial IDCT processors convert, in parallel, the coefficient data from the even and odd processing paths to produce intermediate coefficient values by performing a one dimensional transform. The intermediate coefficient values are transposed in a transpose RAM to produce transposed intermediate coefficient values which are subsequently separated into even and odd processing paths and converted in parallel to produce pixel values by performing a one dimensional transform. The 1-D IDCT processors each include input section circuits which each receive four-bits of 12-bit or 16-bit input values and provides one bit of each of four input values in a four clock cycle time period.

Abstract: An apparatus for transforming the resolution of an image from a first image resolution to a second image resolution using operations in the spatial frequency domain. A first group of transform values which represent the image at the first image resolution are mapped to a second group of transform values which represent the image at the second image resolution in the spatial frequency domain. The apparatus includes stored pre-computed values which are the mapping coefficient values between the first group of transform values and the second group of transform values. The pre-computed values are retrieved from a memory and used to directly map the first group of transform values to the second group of transform values in the spatial frequency domain.

Abstract: A method and device for receiving and storing an electronic television (TV) program guide. In a satellite, cable or broadcast TV system, electronic TV program guides may be coded into the video signals received by the TV receiver. Many currently available TV receivers also allow users to program a list of "select-channels." When the receiver is in its select-channel mode, the receiver only tunes to the channels the user stored in the list of select channels. The present invention limits the memory and processing power required to store an electronic TV program guide by only storing program guide information associated with the channels stored by the user in connection with the select-channels function of the receiver. In receivers having a second tuner, the second tuner may be used to automatically update the stored program guide.

Abstract: A transport decoder 110, for receiving and processing a transport data stream using MPEG-2 formats, includes connections to a physical layer channel interface (channel interface) 112, a buffer memory 114, a host microprocessor 116, audio and video decoders 118/120, and clock signal circuitry 122. The transport decoder also includes an interface to a decoder which does not include a "data valid" input terminal. Upon receipt of encoded data packets, the transport decoder recognizes a frame synchronization byte and transfers an encoded data packet to an external decoder via the interface. The transport decoder sets a count value for a predetermined number of bytes in the encoded data packet and sends the packet data to the external decoder. When the specified number of bytes have been sent to the external decoder, the transport decoder determines if another synchronization byte has been encountered.

Abstract: A microcomputer for automatically controlling an audio output from a receiver. The microcomputer calculates a power signal corresponding to the power of a detected audio input signal, determines whether the calculated power signal is above or below a predetermined power value, generates a power control signal in response to whether the calculated power signal is above or below said predetermined value, and uses the power control signal to automatically maintain a substantially constant audio output from the receiver. In another embodiment, a separate detection circuit calculated the power signal and feeds it to the microcomputer.

Abstract: A notification system for television receivers including a visible alarm and/or an audible alarm that is activated when a certain event occurs. An information signal is extracted from a received television signal and is processed to determine the status of an event. If it is determined that the event occurred, then a control signal is sent to the appropriate alarm to activate that alarm, thereby notifying the user of the event's occurrence. The event may include the reception of a text or graphic message, the televising of a certain television program, and the televising of a television program with a specific program rating. The user may also deactivate the alarm. A personal identification number may be used to restrict access to certain features of the notification system.

Abstract: An apparatus and method, applicable to variable bit rate video and constant bit rate video, is disclosed for replacing "stuffing bytes" with private data. The invention takes advantage of the otherwise wasted resources dedicated to "stuffing" in a data stream in order to insert private data. This is accomplished by inserting useful private data in a Transport Stream instead of the stuffing bits. That is, effectively, a re-multiplexing operation occurs where, based on the existence of certain conditions in a Transport Packet (e.g., stuffing bytes exist), the information necessary to replace stuffing bytes with private data yet still comply with established standards is accomplished. This data generally is referred to as privatestuff data in order to distinguish it from typical private data which may otherwise be encoded into a Transport Stream. The stuffing bytes removed from the Transport Packet may come from an adaptation field in the Transport Header or directly from the Transport Payload or both.

Abstract: A decoder for a video signal encoded according to the MPEG-2 standard includes a single high-bandwidth memory and a digital phase-locked loop. This memory has a single memory port. The memory is used to hold 1) the input bit-stream, 2) first and second reference frames used for motion compensated processing, and 3) image data representing a field that is currently being decoded. The decoder includes circuitry which stores and fetches the bit-stream data, fetches the reference frame data, stores the image data for the field that is currently being decoded in block format and fetches this image data for conversion to raster-scan format. All of these memory access operations are time division multiplexed and use the single memory port. The digital phase locked loop (DPLL) counts pulses of a 27 MHz system clock signal, defined in the MPEG-2 standard, to generate a count value.

Abstract: A system records a single program from a multi-program transport stream that is encoded according to the MPEG-2 standard. The system demultiplexes transport packets from the multi-program transport stream and records the demultiplexed packets on a digital video cassette recorder (DVCR). The system includes circuitry in the encoder which emulates a buffer in the digital recorder that is used to hold the packets to convert the bursty packet data into constant rate data for recording. This emulated buffer controls the overall rate at which packets of the selected program are inserted into the multi-program transport stream by the encoder. As each packet is recorded, a time stamp value, representing when the packet was demultiplexed and a clock count value, representing a number of pulses of a high-frequency system clock signal that occurred during a predetermined number of bytes of the demultiplexed packet are recorded with the demultiplexed packet.

Abstract: A signal processing system for a high resolution digital video tape recorder (VTR) includes circuitry which processes the high resolution video signal to produce a relatively low resolution video signal which may be recorded on the tape with the high resolution video signal. The low resolution video signal is encoded using intra-frame techniques and recorded in fixed-length segments which appear at predetermined locations in the tape tracks. Low resolution segments representing images in different frames may be recovered and combined to produce an image which is suitable for display in trick-play modes. During normal play modes, the data stream representing the high resolution image is recovered in sequence. Accordingly, this high resolution image may be encoded using predictive coding techniques as well as intra-frame techniques.

Abstract: A security system for connecting a first computer network to a second computer network is provided. The security device has a pair of computer motherboards, each of which has a network interface adapter for receiving and transferring communications from a computer network to a transfer adapter to be transmitted to the other computer network through a transfer adapter and network interface adapter provided on the other computer motherboard. Each motherboard provides protocol translation from a first protocol to a second protocol and removes source and destination address information from communications transferred to the other computer motherboard. Application program interface shim software or dynamic link library software provides control of communications between the two motherboards for passing code necessary to request and receive services from the other computer network.

Abstract: A variable length decoder for decoding a variable length code. The variable length decoder includes a code length look-up table which receives n-j bits of an n-bit fixed-length word. A segment of the variable length code value is held in the n-j bits where n and j are integers and j is less than or equal to n. The code length look-up table produces a decoded code length value. The variable length decoder includes a code value look-up table which receives the n-bit fixed-length word and produces a decoded code value of the variable length code.

Abstract: A variable length decoder for decoding a variable length code. The variable length decoder includes a first look-up table for receiving and decoding the most significant bits of the variable length code and for producing a first decoded code corresponding to the most significant bits. The first look-up table means also for outputs a conversion signal. In addition, a second look-up table is provided for receiving and decoding the least significant bits and for producing a second decoded code corresponding to the least significant bits. The first look-up table and the second look-up table decode the most significant bits and the least significant bits at substantially the same time. The decoded output of the look-up tables is provided to a selector. The selector selects the first decoded code or the second decoded code based upon the conversion signal.

Abstract: On the outer surface of the glass face panel 2 of a display device, a first layer 5 of an electrically conductive transparent thin film, a second layer 6 of another transparent thin film consisting essentially of silicon dioxide (SiO.sub.2) or magnesium fluoride (MgF.sub.2), and a third layer 7 of uneven exposed surface, are deposited, whereby a multiplicity of concave regions of said third layer 7 form an interference film together with said first 5 and second layer 6, whereas a multiplicity of convex regions of said third layer form an irregular reflection surface.

Abstract: A method of splicing two compressed video signals which have been encoded according to the standard adopted by the Moving Picture Experts Group (MPEG) determines an amount of null information that is to be inserted between the two video signals in order to ensure that an input buffer of an MPEG decoder does not overflow after receiving the spliced video signals. The method allows a splice to occur after any access unit (picture) in the first compressed video signal. The amount of null information is determined from the data rates of the first and second compressed video signals and the amount of new data which is provided to the buffer before the data is retrieved from the buffer for both the first and second video signals. The video signals are spliced by inserting the null information, as sequence stuffing bits into a buffer immediately after the selected picture in the first video signal. The second video signal is transmitted to the buffer immediately after these stuffing bits.

Abstract: A system and method for providing a video signal during the delay time between when a new channel is selected and when the digital picture is acquired and displayed is disclosed. In particular, the system provides an NTSC-like analog video signal along with a conventional digital television signal such that when a user initially makes a new channel selection, the analog video signal, which can be quickly and easily decoded, is presented for display until the digital television signal is completely decoded and acquired. As soon as the digital television signal is ready for display, the displayed signal switches from the analog video signal to the digital television signal. For purposes of conserving frequency spectrum, the analog video signal is a simple NTSC-like monochrome (i.e., black and white) signal and limited to a 1 MHz band of the available 6 MHz spectrum allocated for each channel.

Abstract: A television receiver having a microprocessor controlled disturbance control system that can operate totally under user control or automatically. The microprocessor generates an on-screen menu which presents noise control options to the user. In the preferred embodiment, the menu options allow the user to ameliorate the effects of impulse noise disturbances, longer duration disturbances, continuous wave form (CW) disturbances, or some combination of the three, without requiring the user to understand the nature of these disturbances. The present invention also provides compensation circuitry for reducing the effects of impulse noise in the video signal that is controlled by responding to the high frequency luminance signal produced by a comb filter, and also responding to the composite video picture signal. High frequency luminance and amplitude variations that are outside of the composite video signal range are indicative of the presence of impulse noise.

Abstract: A parallel decoder for an MPEG-2 encoded video signal includes a deformatter which separates the input bit stream into multiple portions, each representing a respectively different section of the HDTV image. The separate portions are processed in parallel by respective decoders. In order to perform motion compensated processing, each of the four decoders includes a memory that holds data representing the entire image. Each decoder provides its decoded output data to all of the decoders to maintain the data in the respective memories.

Abstract: The present invention is embodied in a decoder for a video signal encoded according to the standard proposed by the Moving Pictures Expert Group (MPEG) of the International Standards Organization (ISO). This decoder employs four sets of processors, each set containing three processors that operate concurrently to decode the MPEG-2 video signal. A variable length decoder processes the input stream to decode the variable length encoded data. The operations performed by this decoding processor change depending on the type of data being decoded. These changes are implemented using a master Digital Signal Processor (DSP) which is programmed according to the MPEG-2 syntax. The data decoded by the VLD processor is either video data or control data. The control data is divided into two types, control data needed to reproduce the image and control data that describes the bit-stream.

Abstract: A system and method for filtering a digital signal having a relatively high data rate uses circuitry which operates at a lower data rate. The filter includes an input section which receives the input signal and which divides the input signal into a plurality of contiguous segments. The system also includes a first filter which receives samples representing one of the plurality of segments and adjacent samples from the next contiguous one of the segments and which filters all of the received samples to produce a first filtered signal. A second filter receives samples of the next contiguous segment and filters those samples to produce a second filtered signal. The filtered signals are combined by providing the samples of the second filtered signal immediately after the samples of the first filtered signal to produce a filtered output signal.