Context based optimal shape coding
نویسندگان
چکیده
This paper investigates how context-based DPCM techniques can be used in conjunction with an operationally rate-distortion (ORD) optimized shape coder. Object contours are approximated by connected second-order spline segments, each defined by three consecutive control points, and, in the case of inter mode, by segments of the motion-compensated reference contours. In scalable intra mode and non-scalable inter mode shape coding, consecutive control points are encoded predictively, using an angle and run framework, with respect to corresponding contexts in the reference frame and the base layer, respectively. We employ a novel criterion for selecting global object motion vectors in the inter mode, which further improves efficiency.
منابع مشابه
Optimal buffered compression and coding mode selection for MPEG-4 shape coding
We propose an optimal buffered compression algorithm for shape coding as defined in the forthcoming MPEG-4 international standard. The MPEG-4 shape coding scheme consists of two steps: first, distortion is introduced by down and up scaling; then, context-based arithmetic encoding is applied. Since arithmetic coding is "lossless," the down up scaling step is considered as a virtual quantizer. We...
متن کاملOptimal Shape Coding under Buffer Constraints
In this paper, we consider an optimal rate control algorithm for shape coding of emerging MPEG-4 compression system. Current MPEG-4 shape coding consists of two sub-steps; First distortion is introduced by scaling down and up way. Then, second, context-based arithmetic coding is applied. Since the arithmetic coding is \lossless", scaling down and up step is considered as a virtual quantizer. We...
متن کاملBinary Shape Coding Using 1-D Distance Values from Baseline
Here we describe a baseline-based binary shape coding method in which arbitrarily shaped object is represented b y the traced 1-D data from baseline and turning point (TP). The shape coding is performed based on contour-based method in each separated shape. There are two coding modes in shape coding, i.e. intra and inter mode as in texture coding. In inter coding mode, object identification, gl...
متن کاملOperational rate-distortion optimal bit allocation between shape and texture for MPEG-4 video coding
MPEG-4 is the first multimedia standard that supports the decoupling of a video object into object shape and object texture information, which consequently brings up the optimal encoding problem for object-based video. In this paper, we present an operational rate-distortion optimal hit allocation scheme between shape and texture for MPEG-4 encoding. Our approach is based on the Lagrange multip...
متن کاملFast Distortion Measurement Using Chord-Length Parameterisation within the Vertex-Based Rate-Distortion Optimal Shape Coding Framework
Existing vertex-based operational rate-distortion (ORD) optimal shape coding algorithms can use a number of different distortion measurement techniques, including the shortest absolute distance (SAD), the distortion band (DB), the tolerance band (TB), and the accurate distortion measurement technique for shape coding (ADMSC). From a computational time perspective, an -point contour requires ( )...
متن کامل