Abstract: A set top box and remote control system, wherein the set top box is provided with preselect keys for storing the program identifier of a user's favorite program. The preselect keys being accessible by a remote control as well as manually.

Abstract: A device comprising an MPEG encoder (2) is provided with a preanalyser (8) which encodes each picture with a fixed step size (Q.sub.2). The preanalyser is coupled to a computing circuit (9) which computes, for each type of (I, P, B) picture, a target value (T) for the number of bits for encoding said picture, as well as a suitable distribution of the target value among the macroblocks of the picture. A proportionally integrating control circuit (7) controls the quantization step size (Q.sub.1). Since the PI control circuit does not introduce any residual errors, the desired number of bits per picture or per group of pictures is achieved within narrow limits. The output signal is eminently suitable for recording and subsequent editing.

Abstract: A master decoder for use with a master smart card and at least one slave decoder for use with a slave smart card are arranged in a pay tv system, wherein the master decoder receives slave entitlement messages from a central management device and writes the slave entitlement messages to the slave smart cards when the slave smart cards are inserted in the master decoder. This ensures that the slave decoders are used within close proximity of the master decoders, such as in the same dwelling.

Abstract: A device for encoding sequences of frames constituted by video-type images of a first frequency (for example, 30 Hz) and film-type images whose original frequency is lower than this first frequency (for example, 24 Hz) and which are converted by means of the "3:2 pulldown" technique.The encoding device comprises;a circuit for detecting the sequences of film-type images from the stream of input data, anda device for preprocessing these sequences for realizing an inverse conversion of the frequency by eliminating, before encoding, the redundant information introduced by the use of the "3:2 pulldown" method.

Abstract: A method and device for performing source transitions in a video system which performs entropy encoding such that a transition occurs only after the fields which define a frame picture have been received by the encoder. The method and device also provides arrangement for ensuring that initially after the switch to the second program source consecutive fields of information from the second program source which will be encoded as a frame picture are provided.

Abstract: A device for transcoding coded digital signals which are representative of a sequence of images, which device comprises a variable length decoding channel (12) followed by a variable length encoding and decoding channel (13), is described. According to the invention, a prediction sub-assembly (140) is connected in cascade between these two channels, and this sub-assembly comprises, in series, between two subtracters (114, 45), a picture memory (41) and a circuit (42) for motion compensation in view of displacement vectors which are representative of the motion of each image. Other implementations are possible, and particularly a scalable one in which said prediction sub-assembly comprises at least two and more generally a plurality of similar encoding and decoding channels arranged in cascade and corresponding to the same number of image quality levels.

Abstract: The picture quality of an MPEG-coded video signal can be improved considerably by modifying selected coefficients after conventional quantization, for example by rendering them zero. The modification is such that the Lagrangian cost D+.lambda.R (D is distortion, R is bitrate) is minimal for a given value of a Lagrange multiplier .lambda.. A relatively simple process is disclosed in which the value of .lambda. is calculated by means of statistical analysis (6) of the picture to be coded. The statistical analysis comprises the estimation of the RD curve on the basis of the amplitude distribution of the coefficients. The searched .lambda. is the derivative of this curve at the desired bitrate.

Abstract: The method divides the buffer memory of an interactive processing and display means in a manner which permits the user to select a portion of a stored image defined by a variable set of address boundaries defining a portion of memory residing within a larger portion of memory defined by another set of address boundaries which in turn resides within a global portion of memory defined by yet another set of address boundaries. The user can vary the variable set of address boundaries so that if they intersect with the address boundaries of the larger portions of memory in which they reside, the buffer memory is updated from a bulk memory.

Abstract: A device for coding a sequence of pictures divided into successive groups of N pictures arranged in picture blocks or macroblocks and including at least one channel for quantization and variable length coding of the blocks or macroblocks, and a bitrate control sub-assembly. The sub-assembly includes a buffer memory and a device for modifying the quantization step used in quantization of the blocks or macroblocks. The buffer memory and the device for modifying the quantization step are connected in series.

Abstract: A high performance variable length decoder which includes a tagging circuit that tags the boundaries of code words in an incoming bit stream, providing a tag stream output and a bussed bit stream output that coincides in time with the tag stream output. The bussed tag stream output is connected to an input of a high speed parallel word length computation circuit, and the bussed bit stream output is connected to an input of a parallel value decoder circuit. The parallel word length computation circuit (word length decoding loop) receives the bussed tag stream and computes (decodes) the length of a singular code word in a singular mode of operation, or the lengths of one or more contiguous code words in a contiguous mode of operation.

Abstract: A high speed variable length decoder with an enhanced architecture for minimizing the propagation delays within the processing paths of the variable length decoder. The variable length decoder includes an input circuit for receiving code words and outputting a sequence of bits on a corresponding sequence of parallel lines that define a decoding window. The input circuit preferably includes a "one-hot" bit stream barrel shifter matrix having a shift input. The decoding window is input to a "one-hot" word length decoder that provides a numbered sequence of output lines. The "one-hot" word length output of the "one-hot" word length decoder is applied to an input of a "one-hot" ring barrel shifter matrix, and an input of a "one-hot" overflow barrel shifter matrix. The output of the "one-hot" ring barrel shifter matrix is a "one-hot" word pointer which shifts the decoding window to the next code word to be decoded.

Abstract: A variable length decoder with adaptive acceleration in processing of an encoded input bit stream which includes an input circuit for receiving the input bit stream and for providing a decoding window that includes a sequence of bits which include one or more code words to be decoded at an output thereof, a code word length decoding circuit for determining the combined length of a combination of two or more code words received from the input circuit in response to a first value of a control signal and for generating a combined length signal representative of the determined combined length, and for determining the length of an individual code word received from the input circuit in response to a second value of the control signal and for generating an individual word length signal representative of the determined length of the individual code word, a computation loop circuit for receiving the combined length signal or the individual word length signal from the code word length decoding circuit and, in response

Abstract: Method and corresponding circuit for estimating motion between pictures composed of interlaced fields. Conventionally, such a circuit comprises a channel for searching for the optimum frame vector, which channel is autonomous with respect to that for searching for the optimum field vectors. In accordance with the invention, the channel for searching for the optimum field vectors is unchanged, but for searching for the optimum frame vector the channel comprises two branches which are no longer autonomous but are arranged at the respective output of each sub-stage for searching for the field vector of the channel with a view to determining an approximation of the motion vector which is sufficient for the searched estimation.

Abstract: By compressing HDTV pictures, they can be recorded on digital SDTV video recorders. Such recorders are widely used in professional studios. The invention relates to a device for formatting the compressed HDTV signal in such a way that the DC values of successive 8*8 picture blocks are processed by SDTV recorders as a smaller but recognizable SDTV sub-picture. Low-cost editing of HDTV programs with standard equipment (SDTV recorders and receivers) is possible with such a device, while the edited final result can be transmitted as a HDTV signal without any further processing operation.

Abstract: A method for generating test patterns to detect an electric shortcircuit, a method for testing electric circuitry while using test patterns so generated, and a tester device for testing electric circuitry with such test patterns. If electric circuitry comprises a plurality of separate nets, a short circuit between an arbitrary pair of nets may be detected by driving the first net at logic zero and the second net at logic one. Measuring the two effective net potentials of the pair of nets will then reveal the short in that two equal potentials would occur. In the case of CMOS technology the driving patterns should also comprise the inverse of the combination above, and also for each pair of nets the number of non-identical overall patterns having the particular 1/0 and 0/1 combinations should be guaranteed and adjustable. The total number of patterns should be minimal. In a test pattern matrix, each column is a single overall pattern; each row is the sequence of signals for the net in question.

Abstract: The disclosed audio amplifier arrangement includes a first amplifier stage for influencing the signal strength of the received audio signal for at least part of the frequency spectrum of an audio signal received through an input. An output amplifier stage amplifies the signal influenced by the first amplifier stage. A detection present in the output amplifier stage detects overloads of the output amplifier stage (3). A control circuit causes, in response to the detection signal, an adjustment to be made of the influence caused by the first amplifier stage if the overload signalled by the detection signal transgresses a certain limit. This limit depends on the magnitude of the adjustment already carried out, so that the degree of overload corresponding to the limit increases when the extent of the adjustment increases.

Abstract: MPEG2-based transmission systems transmit a large number of digital television programs in a single physical channel. Disclosed herein is a "Channel Navigation System" which allows a user to get an overview of the digital programs provided, and to easily select a desired program. The method of the invention includes the transmission (in a separate program of a transport stream) of a video stream representing a mosaic picture, the sub-pictures of which are miniature versions of the video stream of other programs in that transport stream. The method further includes the transmission of information which links the position of each sub-picture within the mosaic picture with the program number from which the sub-picture is derived. The user selects a desired program by merely `pointing and clicking` its miniature version in the mosaic picture.

Abstract: The invention relates to a system for giving an audio-visual presentation consisting of a basic part and at least a complementary part, such as a video film. The system comprises different storage media for storing the basic part and the complementary pan and merging means for merging the basic part with the complementary part into the audio-visual presentation. The complementary part is intended for enhancing the audio-visual presentation quality that can be achieved with the basic part. A provider may provide a basic part free of charge on a CD-i disc, after which the user is to pay for the complementary pan which may be transmitted to him via a telephone line from a databank.

Abstract: A television receiver is provided which includes a vertical deflection circuit which causes interlacing of an interlaced video signal having two fields each with an integral number of scan lines. The vertical deflection circuit including a jog circuit coupled to a vertical deflection yoke, which jog circuit causes a change in current through the vertical deflection yoke during reception of one of the fields. This change in current causes the fields to interlace with each other when scanned on a picture tube.

Abstract: A method of encoding a sequence of images including a moving object, comprises forming an initial template, extracting a mask outlining the object, dividing the template into a plurality (for example sixteen) sub-templates, searching the next frame to find a match with the template, searching the next frame to find a match with each of the sub-templates, determining the displacements of each of the sub-templates with respect to the template, using the displacements to determine affine transform coefficients and performing an affine transform to produce an updated template and updated mask. Encoding is performed at a higher resolution for portions within the outline than for portions outside the outline.