摘要:
A method codes an output bitstream of an input video so the decoded output bitstream has a constant perceived quality. A base layer bitstream having a constant bit-rate is generated from the input video, and an input enhancement layer bitstream is generated from a difference between the input video and the base layer bitstream. Rate and distortion characteristics are extracted from the base layer bitstream and the input enhancement layer bitstream, and an output enhancement layer bitstream having a variable bit-rate is generated from the input enhancement layer bitstream according to the rate and distortion characteristics. The base layer bitstream and the output enhancement layer bitstream, in combination, form an output bitstream having a variable bit-rate and a constant distortion.
摘要:
A method acquires compressed videos. Intra-, or inter-frames of each compressed video are acquired at a fixed sampling rate. Joint analysis is applied concurrently and in parallel to the compressed videos to determine a variable and non-uniform temporal sampling rate for each compressed video so that a combined distortion is minimized and a combined frame rate constraint is satisfied. Each compressed video is then sampled at the associated variable and non-uniform temporal sampling rate to produce output compressed videos having variable temporal resolutions.
摘要:
A method transcodes groups of macroblocks of a partially decoded input bitstream. The groups of macroblocks include intra-mode and inter-mode macroblocks. Each macroblock includes DCT coefficients, and at least one motion vector. The modes of each group of macroblocks are mapped to be identical only if there is an inter-mode block and an intra-mode macroblock in the group. If any of the macroblocks in the group are mapped, then the DCT coefficients and the motion vector for such mapped macroblocks are modified in accordance with the mapping to generate reduced-resolution macroblock for an output compressed bitstream to compensate for drift.
摘要:
A method represents a shape of an object in an image. Portions of the image interior to a boundary of the object are ordered. A medial axis for the ordered portions of the image is derived. The medial axis is segmented to produce an ordered tree. The ordered tree is transformed to a partial ordered tree to represent the shape of the object.
摘要:
A system and a method for decoding at least a portion of an image includes determining a current prediction mode based on a combination of a prediction mode residue and a function of at least one previous prediction mode and decoding the portion of the image using the current prediction mode.
摘要:
A synthetic image block in a synthetic picture is generated for a viewpoint based on a texture image and a depth image. A subset of samples from the texture image are warped to the synthetic image block. Disoccluded samples are marked, and the disoccluded samples in the synthetic image block are filled based on samples in a constrained area. The method and system enables both picture level and block level processing for synthetic reference picture generation. The method can be used for power limited devices, and can also refine the synthetic reference picture quality at a block level to achieve coding gains.
摘要:
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 syndrome vectors. The biometric syndrome vectors can be stored securely, while tolerating an inherent variability of biometric data. The stored biometric syndrome vector is decoded during user authentication using biometric parameters acquired at that time. The syndrome codes can also be used to encrypt and decrypt data. The biometric parameters can be pre-processed to form a binary representation, in which the binary representation has a set of predetermined statistical properties enforced imposed by a set of binary logical conditions.
摘要:
A method decodes a picture in a form of a bit-stream. The picture is encoded and represented by vectors of coefficients. Each coefficient is in a quantized form. A specific coefficient is selected in each vector based on a scan order of the vector. Then, a set of modes is inferred based on characteristics of the specific coefficient. Subsequently, the bit-stream is decoded according to the set of modes.
摘要:
Multiview videos are acquired by overlapping cameras. Side information is used to synthesize multiview videos. A reference picture list is maintained for current frames 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. Alternatively, the depth images corresponding to the multiview videos of the input data, and this data are encoded as part of the bitstream depending on a SKIP type.
摘要:
An encoded video in the form of a bitstream includes a sequence of frames, and each frame is partitioned into encoded blocks. A context for decoding is selected for each encoded block. The bitstream is entropy decoded based on the context to obtain a transform indicator difference. The transform index, which indicates a transform type and a transform direction, is based on the transform indicator difference and a predicted transform indicator. Transform coefficients are obtained from the bitstream, and inverse transformed according to the transform index to produce a decoded video.