The Research On The Dynamic Reconfiguration For Video Codec

With the proliferation of various video coding standards and the increasingapplication requirements, existing traditional video coding standards, whose referencesoftwares are architected as large monolithic and sequential, are unable to satisfy therequirements in highly dynamic video application. MPEG Reconfigurable VideoCoding (RVC) has attracted more attentions because of its flexibility and scalability.From the point of view in coding tools instead of standards, it allows codecs to bedynamicly reconfigured in real time for particular application needs and specifiedoptimization purposes. By re-combining various coding tools, RVC supports thediversities of video content and formats, achieves the reusability and exchangeabilitybetween coding tools from different standards, and is capable of introducing newcoding algorithms into it quickly.After a brief summary of the key techniques in video coding and the drawbacksof traditional standards, this thesis takes the technical features of RVC intoconsideration, and researches on dynamic decoer reconfiguration and the mechanismfor fast incorporation of new coding tools. To solve the drawback of unfullyadaptivity of current RVC framework, novel approaches are proposed. The mainworks are summarized as follows:Firstly, a hybrid decoder reconfiguration is instantiated in the RVC frameworkby grouping the coding tools from AVS-P7and MPEG-4AVC. Also the applicationof dataflow and the process of reconfiguring the decoder are presented. In order toimprove the reusability and exchangeability of coding tools, the issues for partitioningcoding tools in a reasonable granularity are considered. Experimental results showthat compared with MPEG-4AVC baseline profile, the reconfigurable coding systemreduces the computational complexity and guarantees the coding performance at lowbit rate. Moreover, it enriches the RVC video tool library (VTL) by introducing thecoding tools of AVS-P7, and makes it possible to reconfigure codecs for morescenarios. It is shown that the flexibility and reconfigurability of RVC framework tomeet the needs of different applications.Secondly, a methodology of Context-Based Adaptive Reconfigurable VideoCoding (CARVC) is proposed. It implements the context adaptive coding in theframework of RVC, and gurantees the dynamic reconfiguration of decoder according to the time-varying characteristic of the video sequences and specific applicationscenario. A simple codec based on MPEG-4AVC is reconfigured on-the-fly bytransform dynamic adaption in order to demonstrate that the CARVC can get a betterRate-Distortion (R-D) performance than traditional fixed codec. At the same time, itis shown that the process mechanism offered by CARVC framework is flexible toadopt adaptive coding algorithms.