Full motion multiparty videoconferencing using motion compensated visual pattern image sequence coding.

摘要

Video encoding is an important enabling technology for current and future digital video applications. The design of the video encoder determines many, if not all, of the performance characteristics of the video application. Good video encoder design must consider a number of issues that vary according to the requirements of the specific application and/or end user. These issues include encoder rate versus distortion, coding complexity, encoding versus decoding symmetry, variable versus constant bitrate encoding, transmission channel bandwidth and performance characteristics, and compatibility with accepted standard video formats and encoders like MPEG-1, MPEG-2, MPEG-4, H.261 and H.263.; Motion Compensated Visual Pattern Image Sequence Coding (MCVPISC) is a video encoding model introduced here that was uniquely designed to meet the large range of performance criteria encountered in the development of digital video applications. The MCVPISC encoder design is based on a model of the Human Visual System (HVS) that can accommodate these design requirements. It makes use of a visual pattern codebook that represents the most visually significant information for a given fidelity criterion, and incorporates a motion compensation technique that is based on scalable predictive differential encoding. MCVPISC performance results on the MPEG-2 test sequences Football and Tempete indicate excellent coding efficiency and complexity, as well as visual quality. MCVPISC is also demonstrated to be compatible with Discrete Cosine Transform (DCT) based video encoders though a technique named the Linear Complexity VPIC-to-DCT Transform.; Videoconferencing is an important and highly demanding digital video application that was chosen to prototype and demonstrate the capabilities of the MCVPISC software encoding paradigm. In order to express the performance capabilities of the computer videoconferencing system video encoder, the number of full-motion (30 frames/sec) multiparty videoconferencing sessions was chosen as the figure of merit. This metric was analytically modeled in order to create a distinctly new design methodology for videoconferencing system development. Videoconferencing prototype systems for the monochrome and color versions of the MCVPISC encoder were developed. Performance measurements indicate that the MCVPISC encoder can concurrently support multiple full-motion multiparty videoconferencing sessions. The measurements are also demonstrated to be in close agreement with the performance predicted by the model.