Abstract: A quantizer is disclosed in which the quantization errors are symmetrically divided around the respective reconstruction levels. The quantizer prevents quantization errors from accumulating when the quantizer operates in a recursive loop. This is important if such a quantizer is used, inter alia, for compressing image data in the prediction loop of an MPEG decoder. The quantizer prevents such a decoder from drifting away from the encoder's local prediction loop.

Abstract: The invention relates to a method and system for modulating an MPEG-4 FGS compressed video stream for variable-bandwidth transmission. A source of a video stream is provided, and a display having means for generating a control input signal for controlling one or more of video compression, error correction code generation, or symbol constellation mapping. The source video stream is compressed using MPEG-4 FGS compression to generate a compressed output video stream. The video compression is optionally performed based upon the control input signal from the display. Error correction code for the compressed video stream may be added, and its generation and addition may be optionally controlled based upon the control input signal from the display. The resulting video symbols may then be mapped to constellations, with this mapping also optionally controlled based upon the control input signal. The resulting compressed output video stream is then transmitted to the display.

Abstract: A system and method for generating a frequency weighted (FW) matrix for use in a Fine-Granularity-Scalability (FGS) video coding system. The system comprises: a system for plotting the average discrete cosine transform (DCT) residuals versus the zigzag DCT scan line locations for a sample video frame encoded both at a predetermined base layer bit-rate and at approximately three times the predetermined base layer bit-rate; a system for generating the difference plot of DCT residuals versus the zigzag DCT scan line locations for the video frame encoded at both the predetermined base layer bit-rate and at approximately three times the predetermined base layer bit-rate; and a system for matching and normalizing a staircase curve to the average difference plot, wherein the staircase curve values can be further mapped into the weights for the FW matrix.

Abstract: When embedded memory compression is used in the recursive loop of a predictive (MPEG) encoder/decoder, a given compression factor must be achieved. To this end, the image is divided in segments, i.e. groups of (macro)blocks. Each segment is feedforward coded using a quantization strategy such that the compression factor is achieved. This leaves spare bits in the (fixed) segment size. In accordance with the invention, the space left unused by segments is used for refining the quantization of segments having a higher than average activity.

Abstract: A method for storing a block of data consisting of N rows and M columns, which includes the step of transposing the block of data by 90° to thereby produce a transposed block of data consisting of M rows and N columns, and, the step of storing the transposed block of data. The transposed block of data is preferably retrieved by using one or more fetch commands, with the number of fetch commands required to retrieve the transposed block of data being less than the number of fetch commands required to retrieve the same data if stored in its original form, thereby reducing memory bandwidth. In a presently contemplated implementation, the block of data is a reference macroblock of decoded MPEG video data that is used in motion compensation operations, and each of the fetch commands is an A×B fetch command, where A represents the number of columns of data and B represents the number of rows of data to be fetched in response thereto, and wherein further, A>B.

Abstract: In a Fine Granular Video encoding system, a method for determining the number of transmission bits of SNR encoded and temporally encoded video data within a frame to balance image quality and object motion is presented. In accordance with the principles of the invention, a number of transmission bits at a known bit-rate for a quality enhanced video frame and a temporal enhanced video frame is determined to balance image quality and object motion smoothness. In one aspect of the invention, the number of bits transmitted in each frame is determined by comparing a ratio of a measure of video encoded information within the quality enhanced video frame and a measure of video encode information within the quality enhanced video frame and the temporally enhanced video frame to a known threshold level. The number of transmission bits in each enhancement layer is then determined using a first method when the ratio is above a known threshold and using a second method otherwise.

Abstract: The present invention is directed to a variable coding of the bit-planes for a particular source signal. This includes first partitioning or grouping the different bit-planes into embedded sub-signals and then coding each sub-signal. This technique enables an encoder according to the present invention to control and achieve a desired trade-off point between scalability and coding-efficiency. Therefore, in cases where bit or bit-plane level granularity is not required, coding efficiency can be improved by combining two or more bit-planes prior to coding. In addition, since the statistical nature of each bit-plane is different, the level of grouping used across the bit-planes can vary.

Abstract: There is disclosed an apparatus for controlling the transmission of enhancement layer video data for use in a video encoder containing a base layer encoder and an enhancement layer encoder. The base layer encoder receives input video frames and generates compressed base layer video frames suitable for transmission at a base layer bit rate to a streaming video receiver. The enhancement layer encoder compares the input video frames and a processed version of the compressed base layer video frames and generates enhancement layer video data suitable for transmission at a modifiable enhancement layer bit rate to the streaming video receiver. The apparatus comprises a base layer parameter monitor for receiving at least one base layer parameter and, in response thereto, modifying an allocation of the enhancement layer video data among corresponding ones of the compressed base layer video frames.

Abstract: A method for storing a block of data consisting of N rows and M columns, which includes the step of transposing the block of data by 90° to thereby produce a transposed block of data consisting of M rows and N columns, and, the step of storing the transposed block of data. The transposed block of data is preferably retrieved by using one or more fetch commands, with the number of fetch commands required to retrieve the transposed block of data being less than the number of fetch commands required to retrieve the same data if stored in its original form, thereby reducing memory bandwidth. In a presently contemplated implementation, the block of data is a reference macroblock of decoded MPEG video data that is used in motion compensation operations, and each of the fetch commands is an A×B fetch command, where A represents the number of columns of data and B represents the number of rows of data to be fetched in response thereto, and wherein further, A>B.

Abstract: A method and system for dynamically selectively enhancing desired area or areas of a video image which are FGS encoded. The method comprising the steps of determining at least one of the FGS encoded macroblocks in each of the FGS encoded bit-planes associated with the desired area or portion of the video image, determining an order of transmission of each of the determined FGS encoded macroblocks within the transmission sequence and advancing each of the determined FGS encoded macroblocks in the transmission sequence order corresponding to a known level of enhancement, wherein the advanced FGS encoded macroblocks are contained in a bit-plane having a higher transmission priority. In one aspect of the invention, the desired area may be selected by interactively by a user. In another aspect, the desired area or areas may be selected automatically.

Abstract: There is disclosed a video encoder and a video decoder. The video encoder comprises base layer circuitry for receiving an input stream of video frames and generating compressed base layer video data for transmission to a streaming video receiver. The base layer video data comprises original transform coefficients (O) associated with the input stream of video frames and reconstructed base layer transform coefficients (B) associated with the original transform coefficients. The video encoder also comprises enhancement layer circuitry for receiving the original transform coefficients (O) and the reconstructed base layer transform coefficients (B) and generating a residual signal (R) proportional to a difference between the original transform coefficients (O) and the reconstructed base layer transform coefficients (B). The enhancement layer circuitry encodes and sends to the streaming video receiver a sign of the residual signal (R) and the bit planes of the residual signal (R).

Abstract: Coding is provided in which a multi-media object is coded to obtain a bit-stream, and quality information is added to the bit-stream, which quality information indicates a quality of the object in relation to a given position in (or a given part of) the bit-stream. By adding quality information to the bit-stream, jointly storing or transmitting multiple coded objects can be optimized in that the quality of the object can be easily taken into account.

Abstract: A method and system for high resolution formatting of video images and dynamically adjusting the transmission resolution of the high-resolution images is presented. The method first downscales the high-resolution images and encodes the downscaled images into base layer frames. Quality enhancement layer data is generated from the downscaled video images and the encoded data contained in corresponding base layer frames. The quality enhancement layer data is encoded into quality enhancement layer frames. The data contained in the base layer frames and corresponding quality layer frames are then upscaled and spatial scalability data is determined from the upscaled data and the original image. The spatial scalability data is then encoded into spatial scalability data. During transmission of the encoded video image, each available encoded frame is transmitted using different amounts or portions of the enhancement layers so as to occupy the available bandwidth.

Abstract: A method and system for producing decoding the transmission of high-resolution images transmitted as a low resolution spatially scalable FGS encoded base layer and at least one enhancement layer is presented. The low resolution received base layer is representative of a downscaled image of the original image. In this manner, a minimum resolution base layer is transmitted and higher resolutions may be obtained and utilized depending on the available bandwidth and the receiving system resolution capability. In one aspect of the invention, the base layer is decoded and a quality enhancement is next applied to the base layer. The combined base layer and quality layer video frames are then upscaled and the upscaled image is combined with a decoded spatial enhancement layer information. The spatial enhancement layer information fills in resolution lacking in the upscaled base layer/quality layer image. Thus, a high resolution image is formed.

Abstract: A scalable video coding scheme having a single motion compensation loop that generates bi-directional predicted frames (B frames) or predicted frames and bi-directional predicted frames and (P and B frames) coded entirely with a scalable codec.

Abstract: A method for streaming enhancement layer video frame data on a variable bandwidth network involves coding original uncoded video data with a non-scalable codec to generate I and P base layer frames; generating residual temporal B frames and SNR I and P frames from the original uncoded video data and the base layer frames; coding the temporal and SNR frames with a scalable codec; determining an available bandwidth of the variable bandwidth network; transmitting at least portions of the scalable coded temporal frames when the available bandwidth is a first bandwidth ranging between a minimum bit-rate allocated for transmitting only base layer frames and a predetermined bit-rate which is below a maximum bit-rate of the network; and additionally transmitting remaining portions of the scalable coded temporal frames and at least portions of the scalable coded SNR frames when the available bandwidth is a second bandwidth extending between the predetermined bit-rate and the maximum bit-rate of the network.

Abstract: A video coding technique having motion compensation within a fine granular scalable coded enhancement layer. In one embodiment, the video coding technique involves a two-loop prediction-based enhancement layer including non-motion-predicted enhancement layer I- and P-frames and motion-predicted enhancement layer B-frames. The motion-predicted enhancement layer B-frames are computed using: 1) motion-prediction from two temporally adjacent differential I- and P- or P- and P- frame residuals, and 2) the differential B-frame residuals obtained by subtracting the decoded base layer B-frame residuals from the original base layer B-frame residuals. In a second embodiment, the enhancement layer further includes motion-predicted enhancement layer P-frames.

Abstract: A video coding technique having motion compensation for bi-directional predicted frames (B-frames) and predicted frames (P-frames). The video coding technique involves a single-loop prediction-based base layer which includes base layer B- and/or P-frames that are generated from “extended” or “enhanced” base layer reference frames during base layer coding.

Abstract: Improved efficiency in transmission of FGS encoded video data is achieved by reducing the transmission of overhead information items necessary to decode the received video data. After establishing an initial or first set of criteria for selectively enhancing areas within an image, each subsequent transmission frame includes an indicator that informs a receiving system to decode the current frame using the previously established criteria. In one aspect of the invention, the initial criteria are shift factor values specifying selectively enhanced areas of an image. In another aspect of the invention, the criteria include position, displacement vector, size and enhancement factor for at least one area of interest with in an image. In still another aspect of the invention, the criteria are known fixed values contained at both the transmitting and receiving systems.

Abstract: There is disclosed an adaptive quantization controller for use in a video encoder comprising a base layer circuit for receiving an input stream of video frames and generating compressed base layer video frames suitable for transmission to a streaming video receiver and an enhancement layer circuit for receiving the input stream of video frames and a decoded version of the compressed base layer video frames and generating enhancement layer video data associated with, and allocated to, corresponding ones of the compressed base layer video frames. The adaptive quantization controller receives at least one quantization parameter from the base layer circuit and, in response thereto, determines a corresponding shifting factor for shifting a bit plane associated with the enhancement layer video data. The adaptive quantizaion controller also modifies a data field in the enhancement layer video data to cause the video streaming receiver to assign a higher decoding priority to the shifted bit plane.