Abstract: A method is provided for decoding a bit stream representing an image that has been encoded The method includes the steps of: performing an entropy decoding of the bit stream to form a plurality of transform coefficents and a plurality of motion vectors; performing an inverse transformation on the plurality of transform coefficients to form a plurality of error blocks; determining a plurality of predicted blocks based on bidirectional motion estimation that employs the motion vectors, wherein the bidirectional motion estimation includes a direct prediction mode and a second prediction mode; and, adding the plurality of error blocks to the plurality of predicted blocks to form the image. The second prediction mode may include forward, backward, and interpolated prediction modes.

Abstract: A system and method for reproducing a multimedia data signal on a terminal. A terminal capability node is instantiated and the terminal capability is evaluated. The value of a capability is set, and the value is then altered based upon the capability of the evaluated terminal.

Abstract: A method is provided for decoding a bit stream representing an image that has been encoded. The method includes the steps of: performing an entropy decoding of the bit stream to form a plurality of transform coefficents and a plurality of motion vectors; performing an inverse transformation on the plurality of transform coefficients to form a plurality of error blocks; determining a plurality of predicted blocks based on bidirectional motion estimation that employs the motion vectors, wherein the bidirectional motion estimation includes a direct prediction mode and a second prediction mode; and, adding the plurality of error blocks to the plurality of predicted blocks to form the image. The second prediction mode may include forward, backward, and interpolated prediction modes.

Abstract: A quantizer and dequantizer for use in a video coding system that applies non linear, piece-wise linear scaling functions to video information signals based on a value of a variable quantization parameter. The quantizer and dequantizer apply different non linear, piece-wise linear scaling functions to a DC luminance signal, a DC chrominance signal and an AC chrominance signal. A code for reporting updates of the value of the quantization parameter is interpreted to require larger changes when the quantization parameter initially is large and smaller changes when the quantization parameter initially is small.

Abstract: A predictive video coder performs gradient prediction based on previous blocks of image data. For a new block of image data, the prediction determines a horizontal gradient and a vertical gradient from a block diagonally above the new block (vertically above a previous horizontally adjacent block). Based on these gradients, the encoder predicts image information based on image information of either the horizontally adjacent block or a block vertically adjacent to the new block. The encoder determines a residual that is transmitted in an output bitstream. The decoder performs the identical gradient prediction and predicts image information without need for overhead information. The decoder computes the actual information based on the predicted information and the residual from the bitstream.

Abstract: A quantizer and dequantizer for use in a video coding system that applies non linear, piece-wise linear scaling functions to video information signals based on a value of a variable quantization parameter. The quantizer and dequantizer apply different non linear, piece-wise linear scaling functions to a DC luminance signal, a DC chrominance signal and an AC chrominance signal. A code for reporting updates of the value of the quantization parameter is interpreted to require larger changes when the quantization parameter initially is large and smaller changes when the quantization parameter initially is small.

Abstract: A predictive video coder performs gradient prediction based on previous blocks of image data. For a new block of image data, the prediction determines a horizontal gradient and a vertical gradient from a block diagonally above the new block (vertically above a previous horizontally adjacent block). Based on these gradients, the encoder predicts image information based on image information of either the horizontally adjacent block or a block vertically adjacent to the new block. The encoder determines a residual that is transmitted in an output bitstream. The decoder performs the identical gradient prediction and predicts image information without need for overhead information. The decoder computes the actual information based on the predicted information and the residual from the bitstream.

Abstract: A system and method for reproducing a multimedia data signal on a terminal. A terminal capability node is instantiated and the terminal capability is evaluated. The value of a capability is set, and the value is then altered based upon the capability of the evaluated terminal.

Abstract: A system and method for reproducing a multimedia data signal on a terminal. A terminal capability node is instantiated and the terminal capability is evaluated. The value of a capability is set, and the value is then altered based upon the capability of the evaluated terminal.

Abstract: A video coding system that codes video objects as scalable video object layers. Data of each video object may be segregated into one or more layers. A base layer contains sufficient information to decode a basic representation of the video object. Enhancement layers contain supplementary data regarding the video object that, if decoded, enhance the basic representation obtained from the base layer. The present invention thus provides a coding scheme suitable for use with decoders of varying processing power. A simple decoder may decode only the base layer of video objects to obtain the basic representation. However, more powerful decoders may decode the base layer data of video objects and additional enhancement layer data to obtain improved decoded output. The coding scheme supports enhancement of both the spatial resolution and the temporal resolution of video objects.

Abstract: A method for increasing compression efficiency of a stereoscopic image encoder employed for compressively encoding first and second signals representing respective first and second views of a stereoscopic image, comprises: providing a first histogram of the first view and a second histogram of the second view, the first and second histograms representing a frequency of occurrence of a characteristic component of the first and second views, respectively; comparing the first histogram of the first view with the second histogram of the second view and estimating the mismatch in gain, a, and mismatch in offset, b, between the first and second views; correcting the stereoscopic image by multiplying the gain a and the second signal to obtain a gain corrected second signal for the stereoscopic image and adding the offset b to the gain corrected second signal to obtain a gain and offset corrected second signal, the gain and offset corrected second signal being obtained prior to encoding to increase encoding efficienc

Abstract: In a system and method for transmitting and displaying multiple different views of a scene, three or more simultaneous scene signals, representing multiple different views of a scene, are provided by an appropriate camera arrangement to a spatial multiplexer. The size and resolution of the scene signals are reduced as necessary to combine the multiple scene signals into two super-view signals. The super-view signals are encoded using compression based on redundancies between the two super-views and then transmitted. A decoder receives the transmitted data signal and extracts the two super-view signals according to the inverse of the encoding operation. A spatial demultiplexer recovers the individual scene signals from the decoded super-view signals in accordance with a defined multiplexed order and arrangement. The scene signals are then interpolated as needed to restore the original resolution and size and subsequently displayed.

Abstract: A video encoding method and apparatus is shown wherein image information is represented as a plurality of pixels, the pixels are organized into blocks, pixels transposition is performed on image information at the boundaries of the blocks, the blocks are transform coded and quantized. Pixel transposition involves transposition of alternate pixels at the boundaries of blocks with pixels of neighboring blocks found in a pre-determined direction. The pre-determined direction may be fixed by a system or may be applied on an image by image basis. In the event that the pre-determined direction is not established by a system, a pixel transposition circuit includes a transposition keyword in the output bit stream which is used by a decoded to determine the direction of pixel transposition.

Abstract: A method and apparatus for generating region frames from video frames are disclosed which employs an industry standard encoder to lessen the negative impact on the quality of the transmitted video sequence while consuming fewer bits. The invention utilizes image segmentation and color replacement techniques to create the region frames. Each region frame includes a subject region, zero or more previously segmented regions and zero or more non-subject regions. The subject region is defined by the pixels of the original video frame. The previously segmented regions and non-subject regions are assigned replacement pixels P.sub.n,y and C.sub.n, respectively. The replacement pixel C.sub.n is chosen to indicate a color that is not likely to be confused with any color in the subject region R.sub.n. The replacement pixels P.sub.n,y are chosen such that the compression ratio of the region frame data is maximized.

Abstract: A predictive video coder performs gradient prediction based on previous blocks of image data. For a new block of image data, the prediction determines a horizontal gradient and a vertical gradient from a block diagonally above the new block (vertically above a previous horizontally adjacent block). Based on these gradients, the encoder predicts image information based on image information of either the horizontally adjacent block or a block vertically adjacent to the new block. The encoder determines a residual that is transmitted in an output bitstream. The decoder performs the identical gradient prediction and predicts image information without need for overhead information. The decoder computes the actual information based on the predicted information and the residual from the bitstream.

Abstract: Method and apparatus for generating variable length coded for video encoding. A plurality of memory tables contain variable length codes tailored to patterns of input video information that is likely to be input to the variable length encoder. The patterns are determined in large part by a value of a quantizer used in video encoding. A separate memory table containing separate variable length codes is established for each of a plurality of quantization parameter values. The quantization parameter is input to the encoder to enable one of the memory tables and the video information is input to the enabled table to generate the variable length code.

Abstract: A client-server network enables interconnection to both the Internet and switched network. In response to a received client service request, a connection is established over the Internet between a client and a server. Client information transmitted from the client to the server over the Internet connection is used to enable the server to provide the requested service by establishing a switched network connection to the client using a client's communication number determined from the client information.

Abstract: Real time delivery of multimedia information accessed either through the Internet, or otherwise, simultaneously, or sequentially time delayed to one more users, is enabled by delivering the multimedia information over a switched network via a multipoint control unit. A client establishes a connection with a server, or other remote location where desired multimedia information is resident, identifies the desired multimedia information and provides client information identifying the locations of the users. The client information may include the telephone numbers or other access numbers of each of the multiple users. The multimedia information is then delivered by a multimedia server to a bridging apparatus through a switched network guaranteeing high quality of service, secure connection and billing control. Connecting one or more users to a live agent is also made possible by providing the telephone numbers of the users and the live agent directly to the multipoint control unit.

Abstract: A synthesized signing image is generated which includes an original image of a subject and a sign image superimposed on the original subject image. The sign image is selected from a sign language database based on the speech (i.e., a letter or word) spoken by the subject. Based on the size and tone (intensity) of the subject's face in the original image, the database sign image is modified to match the intensity and have a proportional size to the subject's face. The modified database sign image is then superimposed on the original image of the subject to create a synthesized image in which the subject appears to be signing.

Abstract: A system and method for enhancing interactive communication between video conferencing devices of the type in which a delay is inserted into the audio transmission path to provide lip synchronization of the image and speech of the respective users thereof. Each video conferencing device includes a display device for displaying images of at least one communicating party and a speech communicating system for communicating with the communicating party. In accordance with one embodiment of the invention, a speech detecting circuit detects an utterance by a first user of a first video conferencing apparatus. An audible or visual indication is provided to at least a second user of a second video conferencing apparatus before the utterance is reproduced. As a result, the potential for simultaneous speaking by two or more users is substantially reduced.