Abstract: A adaptive complexity control algorithm is proposed to reduce the complexity of H.264 motion estimation. The main idea is to limit the complexity of motion estimation based on the expected RD coding gain loss. In order to efficiently reduce the complexity to desired level, ACC is designed to provide complexity scalability in motion estimation so as to provide flexible tradeoff between video quality and computational complexity. With the proposed algorithm, we demonstrate that complexity of motion estimation can be reduced by ¾ without significant RD performance degradation.

Abstract: A method randomly accesses multiview videos. Multiview videos are acquired of a scene with corresponding cameras arranged at poses, such that there is view overlap between any pair of cameras. V-frames are generated from the multiview videos. The V-frames are encoded using only spatial prediction. Then, the V-frames are inserted periodically in an encoded bit stream to provide random temporal access to the multiview videos. Additional view dependency information enables the decoding of a reduced number of frames prior to accessing randomly a target frame for a specified view and time, and decoding the target frame.

Abstract: A method processes a multiview videos of a scene, in which each video is acquired by a corresponding camera arranged at a particular pose, and in which a view of each camera overlaps with the view of at least one other camera. Side information for synthesizing a particular view of the multiview video is obtained in either an encoder or decoder. A synthesized multiview video is synthesized from the multiview videos and the side information. A reference picture list is maintained for each current frame of each of the multiview videos, the reference picture indexes temporal reference pictures and spatial reference pictures of the acquired multiview videos and the synthesized reference pictures of the synthesized multiview video. Each current frame of the multiview videos is predicted according to reference pictures indexed by the associated reference picture list with a skip mode and a direct mode, whereby the side information is inferred from the synthesized reference picture.

Abstract: A method encodes a video as video objects. For each candidate object, a quantizer parameter and a skip parameter that jointly minimizes an average total distortion in the video are determined while satisfying predetermined constraints. The average total distortion includes spatial distortion of coded objects and spatial and temporal distortion of uncoded objects. Then, the candidate objects is encoded as the coded objects with the quantizer parameter and the skip parameter, and the candidate objects is skipped as the uncoded objects with the skip parameter.

Abstract: A method processes a multiview videos of a scene, in which each video is acquired by a corresponding camera arranged at a particular pose, and in which a view of each camera overlaps with the view of at least one other camera. Side information for synthesizing a particular view of the multiview video is obtained in either an encoder or decoder. A synthesized multiview video is synthesized from the of multiview videos and the side information. A reference picture list is maintained for each current frame of each of the multiview videos, the reference picture indexes temporal reference pictures and spatial reference pictures of the acquired multiview videos and the synthesized reference pictures of the synthesized multiview video. Each current frame of the multiview videos is predicted according to reference pictures indexed by the associated reference picture list.

Abstract: A method and system reduces the spatial resolution of a compressed bitstream of a sequence of frames of a video signal by first decoding the frames, and storing the decoded frames in a first frame buffer. While performing the decoding, motion compensating is performed with full resolution motion vectors of the stored decoded frames. The decoded frames are then down-sampled to a reduced resolution, and stored in a second frame buffer. The reduced resolution frames are partially encoded to produce a reduced resolution compressed bitstream of the video. While performing the partial encoding, motion compensation is performed with reduced resolution motion vectors of the stored reduced resolution frames.

Abstract: A method and system transcodes an input video to a lower spatial resolution. The input video is first decoded into pictures. Each picture includes a set of macroblocks. Each picture sub-sampled to a downscaled picture having a lower spatial resolution. A quantization scale is selected for each macroblock in the downscaled picture. A set of motion vectors is generated for each macroblock in the downscaled picture. A multiplier value based on the quantization scale is determined for each macroblock in the downscaled picture. One of a plurality of encoding modes is selected for each macroblock in the downscaled picture according to the quantization scale, the motion vectors, and the multiplier value. Then, each macroblock in each downscaled picture is encoded according to the quantization scale, the selected encoding mode, and the set of motion vectors to produce an output video having a lower spatial resolution that the input video.

Abstract: A method estimates bit rates for sets of coding parameters, based on characteristics of a channel, and an end-to-end distortion is estimated based on signal statistics of the video. A particular set of coding parameters that satisfies an available bit rate of the channel and that minimizes the end-to-end distortion of the video is selected. Motion compensated multiple descriptions of the video are encoded according to the selected set of coding parameters.

Abstract: A method and system connects a first terminal via multiple networks to a second terminal. An environment description is acquired and parsed by a description parser into cost parameters using a set of rules. An objective function evaluates the cost parameters to determine an optimal path to connect the first terminal to the second terminal through the multiple networks using a switch. The selection of the optimal path can be done periodically during a particular application session.

Abstract: A method adaptively encodes a video including a sequence of images, where each image is a picture of two fields. Each image is first separated into a top-field and a bottom-field. Motion activity is extracted from the top-field and the bottom-field, and each image is encoded using either frame encoding or field encoding depending on the extracted motion activity.

Abstract: A method compensates for drift in macroblocks of a partially decoded input bitstream. The macroblocks include intra-mode and inter-mode macroblocks, and each macroblock includes DCT coefficients, and at least one motion vector. An estimate of drift is measured in the partially decoded input bitstream. The estimated drift is translated into an intra refresh rate. The modes of inter-mode macroblock are mapped to intra-mode macroblock according to the refresh rate. The DCT coefficients and the motion vector for each changed macroblock are modified in accordance with the mapping for each changed macroblock.

Abstract: A method randomly accesses multiview videos. Multiview videos are acquired of a scene with corresponding cameras arranged at poses, such that there is view overlap between any pair of cameras. V-frames are generated from the multiview videos. The V-frames are encoded using only spatial prediction. Then, the V-frames are inserted periodically in an encoded bitstream to provide random temporal access to the multiview videos.

Abstract: A system and method manages multiview videos. A reference picture list is maintained for each current frame of multiple multiview videos. The reference picture list indexes temporal reference pictures, spatial reference pictures and synthesized reference pictures of the multiview videos. Then, each current frame of the multiview videos is predicted according to reference pictures indexed by the associated reference picture list during encoding and decoding.

Abstract: A system and method synthesizes multiview videos. Multiview videos are acquired of a scene with corresponding cameras arranged at a poses such that there is view overlap between any pair of cameras. A synthesized multiview video is generated from the acquired multiview videos for a virtual camera. A reference picture list is maintained for each current frame of each of the multiview videos and the synthesized video. The reference picture list indexes temporal reference pictures and spatial reference pictures of the acquired multiview videos and the synthesized reference pictures of the synthesized multiview video. Then, each current frame of the multiview videos is predicted according to reference pictures indexed by the associated reference picture list during encoding and decoding.

Abstract: A method decomposes multiview video acquired of a scene by multiple cameras. Each multiview video includes a sequence of frames, and each camera provides a different view of the scene. A prediction mode is selected from a temporal prediction mode, a spatial prediction mode, and a view interpolation prediction mode. The multiview videos are then decomposed into low band frames, high band frames, and side information according to the selected prediction mode.

Abstract: First biometric parameters are acquired from a user. Input data are encrypted according to the biometric parameters to produce ciphertext. The biometric parameters are encoded using a syndrome encoder to produce a syndrome code. The ciphertext and the syndrome code are associated with each other and stored in a computer readable media so that only the same user can subsequently decrypt the cipher text.

Abstract: Biometric parameters acquired from human faces, voices, fingerprints, and irises are used for user authentication and access control. Because the biometric parameters are continuous and vary from one reading to the next, syndrome codes are applied to determine biometric syndromes. The biometric syndromes can be stored securely, while tolerating an inherent variability of biometric data. The stored biometric syndrome is decoded during user authentication using biometric parameters acquired at that time. Specifically, during enrollment, enrollment biometric parameters are acquired from a user and encoded as a syndrome. A hash function is applied to the syndrome to produce an enrollment hash. The syndrome and hash as stored in a database. During user authentication, the enrollment syndrome is decoded using a syndrome decoder and authentication biometric parameters of the user to produce decoded biometric parameters.

Abstract: A method transcodes an image in the form of an encoded input bitstream. The input bitstream includes quality layers, each quality layer includes a resolution levels, each resolution level includes components, each component includes precincts, and each precinct includes a packet partition location, a header length, and a body length. The input bitstream is decoded partially to obtain a structure of the encoded input bitstream. Coordinates of a region-of-interest in the image are specified, and progressive parameters are defined. The partially decoded input bitstream is then encoded according to the structure, the coordinates, and the progressive parameters to obtain an encoded output bitstream.

Abstract: A system delivers multimedia services to mobile devices via a network by first registering a mobile device with a service manager connected to the mobile device via the network. Application service providers are connected to the service manager via the network. Each application service provider is associated with particular multimedia services. An environment description to be associated with the mobile device is acquired, and a particular application service provider is identified according to the environment description, and then selected services provided by the particular application service provider are delivered to the mobile device according to the environment description via the network.

Abstract: A method compresses a set of correlated signals by first converting each signal to a sequence of integers, which are further organized as a set of bit-planes. This can be done by signal transformation and quantization. An inverse accumulator is applied to each bit-plane to produce a bit-plane of shifted bits, which are permuted according to a predetermined permutation to produce bit-planes of permuted bits. Each bit-plane of permuted bits is partitioned into a set of blocks of bits. Syndrome bits are generated for each block of bits according to a rate-adaptive base code. Subsequently, the syndrome bits can be decompressed in a decoder to recover the original correlated signals. For each bit-plane of the corresponding signal, a bit probability estimate is generated. Then, the bit-plane is reconstructed using the syndrome bits and the bit probability estimate.