Scientific-atlanta, Inc.

Leitch Technology International Inc.

Keith Lucas

William F Van Rassel

Paul D Israelsen

Robert K Yoneda

Cameron Bates

Nigel Seth-Smith

Samson Lim

John D Lowry

Anthony John Wasilewski

William Van Rassel

Watermark data consisting of known two-dimensional codeword patterns are added to a first portion of each video frame by modifying parameters defining the first portion. Limited randomization of the spatial position of the codeword pattern is also provided. During a decoding process, a predictor continuously estimates the current value of the modified parameters. In one embodiment of the present invention, the predictor employs video samples taken from unmodified areas of the frame to provide the estimates. The estimated parameter values are subtracted from the actual parameter values to provide an error signal. Multiple correlators attempt to detect the presence of the codeword pattern in the error signal within a range of spatial locations surrounding a nominal position of the codeword pattern. The use of multiple correlators provides immunity to feasible attacks aimed at damaging or obscuring the watermark.

Method and apparatus for video watermarking

A video signal is encrypted by pseudo-random variation of portions of lines thereof to be horizontally scanned that are devoid of video information. Thus, the durations of line blanking intervals may be varied. The variation is done in accordance with an encryption keys which is employed at the receiver to decrypt the encrypted video signal.

Encryption and decryption (scrambling and unscrambling) of video signals

A plurality of digital services are carried in a multiplex data stream to a plurality of remote locations. The multiplex data stream comprises a continuous sequence of frames. Each frame comprises two consecutive fields, and each field comprises a plurality of lines. A first group of the lines in each field defines a transport layer region of that field, and a second group of the lines defines a service data region. Portions of the service data region of each field are allocated to respective ones of the video services in proportion to respective data rates of each service. A multiplex control packet is generated for each field that specifies, for each service, which portion of the service data region is allocated to that service. The multiplex control packet for each field is inserted into the transport layer region of that field along with a plurality of other packets that contain system related information. A multiplex map is generated and inserted in the first line of the transport layer of each field that specifies the number and location of packets within the transport layer. A multiplex map is transmitted with each field, and therefore, the number and location of packets within the transport layer may be dynamically adjusted on a per field basis. Additionally, the service allocation within the service data region of each field may be altered on a per frame basis to support statistical multiplexing.

System and method for transmitting a plurality of digital services

A method for generating a picture-in-picture digital television frame comprises the steps of: converting a first analog television signal into a first digital frame comprising a first prescribed number of pixels; deriving a mean-only frame from the first digital frame, the mean-only frame comprising a second prescribed number of pixels; creating an insertion frame on the basis of the mean-only frame; and inserting the insertion frame into a second digital frame, thereby generating a picture-in-picture digital television frame. A Vector Quantization receiver/decoder comprises a mean-only decode section 20, a full decode section 30, and an image inserter 40.

Methods and apparatus for generating a picture-in-picture digital

A method of communicating data from a first location to a second location employing a vector quantization data compression technique that allows users to select the reproduction quality of the transmitted vector quantized data. According to the method, data is encoded (compressed) from the last level of a first tree search vector quantization codebook at the first location. A second tree search vector quantization codebook is provided at the second location having a number of levels equal to or less than the number of levels in the first codebook. The reproduction quality of the transmitted vector quantized data is a function of the number of levels in the second codebook.

Method for selecting reproduction quality of transmitted vector

A method and apparatus for processing fields of a video signal that are to be combined into a frame, compressed and communicated over a digital communications system. The processing technique increases the spatial correlation between pixels at a cost of slightly reduced resolution in areas of the frame where there is movement. The method employs a motion detector to separate moving and non-moving areas of the frame. A simple combination of lines from a first field and a second field can be used in static areas. In moving areas, a digital filter is applied to the fields to increase correlation in the resulting field. A digital compression technique such as vector quantization is applied to the resulting frame-based signal.

Motion filter for digital television system

A method and apparatus for low-frequency removal in vector quantization of an image frame. An image frame is converted to plurality of input vectors. A mean value of each input vector is determined and transmitted to a plurality of reception sites. A low-frequency component of each input vector is then determined and removed from the input vector. A scalar mean value of each low-frequency removed vector is then determined and subtracted therefrom to produce a residual vector. The residual vectors are then vector quantized and the vector quantized data is transmitted to the reception sites. At a reception site, the transmitted mean values and vector quantized data are received and each input vector is reproduced therefrom. From the reproduced input vectors, the image frame is recreated for display at the reception site.

Method and apparatus for low frequency removal in vector quantization

A method and apparatus is disclosed wherein fixed rate vector quantized data is transmitted from a first location to a second location via a first medium. The fixed rate vector quantized data is received at the second location and transformed to variable rate vector quantized data. Then, the transformed variable rate vector quantized data is transmitted to a third location via a second medium. At the third location, the variable rate vector quantized data may be received, and if desired, transformed back to fixed rate form. A distortion adaptive vector quantization method is employed to transform the fixed rate vector quantization data to variable rate vector quantization data.

Method and apparatus for transforming between fixed-rate vector

A vector quantization me employs mirrored input vectors to increase the reproduction quality of transmitted vector quantized data. A codevector is selected from a vector quantization codebook for each possible orientation of an input vector. The codevector having the smallest distortion relative to the input vector is selected for transmission. An identification code identifying the selected orientation is also transmitted.

Vector quantization method employing mirrored input vectors to search

A method for encoding a high definition television signal comprising a first frequency spectrum portion for standard resolution and a second high frequency spectrum portion for high resolution consistent with the B-MAC composite signal format comprises the steps or orthogonally sampling the high definition signal, diagonally filtering diagonal resolution information, and decimating alternate samples of alternate lines for folding in high frequency horizontal resolution information by means of a skew-symmetric low-pass filter. A method at a standard television resolution receiver for decoding the high-definition television signal uses a simple low pass filter to recover the baseband television spectrum at standard television resolution. A method at a high-definition television receiver comprises the steps of unfolding the high frequency horizontal resolution information and thereafter line doubling the unfolded high frequency resolution informtion to improve vertical resolution of the high-definition television signal. Thus, the encoding method is compatible for reception at either a standard resolution or high-definition television receiver.

High definition B-MAC television signal transmission system

A high definition B-MAC television signal transmission system comprises a scan converter and a signal pre-processor for accepting signals in various high definition formats. In particular, an 1125 line or 1050 line to 525 line scan converter is required due to the preponderance of at least 1125 line and to some extent 1050 line 60 Hertz field rate format high definition television studio equipment. The scan converter includes circuitry for converting from horizontal to vertical scan format via first and second field stores. A phase shift transversal filter spatially shifts every sample of each field by 1/4 line. In alternate fields, the direction of spatial shifting reverses. For an interlace output, alternate line samples are discarded or for a sequential scan output, all samples are used. The output of the transversal filter is scan converted to reassume a horizontal scan format. Three field stores are used to buffer the input and output fields rates such that one field of samples is dropped every one thousand fields in order to convert from a 60 Hz field rate to 59.94 Hz. At the same time, the coefficients of the transversal filter are reversed for the next field of samples after the dropped field. The scan converter provides a digital 525 line 1:2 or, in another embodiment with two field rate converter circuits, a 1:1 format output. According to B-MAC signal processing, an interlace 525 line output is provided to a pre-processor which additionally may accept a 525 line analog RGB input. Also, the pre-processor may generate its own test pattern signals.

Scan converter for a high definition television system

A method for increasing the definition of an NTSC video signal using an augmentation channel involves the generation of both a line summation signal as well as a line difference signal. From the line summation signal, a horizontal detail signal may be derived which may be diagonally filtered and added to a diagonally filtered vertical detail signal and transmitted in a bandwidth of approximately 2.5 mega-hertz. Furthermore, the line summation signal may be applied for the derivation of a standard NTSC video signal which is transmitted separately from the augmentation channel. Decoder apparatus comprises a single digital diagonal filter having complimentary output functions resulting in both improved horizontal and vertical resolution at low cost.

Method and apparatus for increasing the definiton of an NTSC video

A subscription television system in which individual decoders are enabled to receive individually addressed messages is disclosed. The composite signal, including video and teletext, also comprises addressed packets which are detected by decoders and which indicate that a message addressed to a particular subscriber is forthcoming, and system control data. In a preferred embodiment, both addressed packets and teletext are encrypted. The addressed packet is decrypted using a decoder-specific code and a transmitted code, while the teletext message is decrypted using a decryption key contained in the system control data. The teletext message cannot be received until the addressed packet has been decrypted. Therefore, redundant levels of security are provided to the system. Messages for display to the user can be selected in response to user initiated commands, in response to decoder initiation, or in response to the transmitter.

Communications format for a subscription television system permitting

A subscription television system for distributing program material protected by copyright to subscribers comprises a transmitter including a data insertion circuit for inserting a control bit in a transmitted signal comprising other control data and the protected program material. A receiver of the system includes a memory for storing a pre-assigned subscriber identification. Upon receipt and identification of the control bit at the receiver, the receiver inserts the subscriber identification into the program material so that any unauthorized copy made of the program material may be found to include the subscriber identification.

Method for controlling copying of protected information transmitted over

An information display scheme for displaying subscriber unique information to subscribers of a subscription communications system. The system comprises template page receiving means coupled to the communications system for receiving a template page as a format for the subscriber unique information, storage means coupled to the template page receiving means for storing the template page and logic means coupled to the communications system and to the storage means for locally generating and maintaining at least some of the subscriber unique information. The logic means combines the subscriber unique information with the template page for display to the subscriber.

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Richmond Hill, Canada

Keith Lucas