DEVELOPMENT OF A SOFTWARE MPEG-4 ENCODER FOR REAL-TIME APPLICATIONS

摘要

A high-quality software MPEG-4 encoder for real-time applications is proposed. A low-complexity 1-pass VBR (variable bitrate) control method is introduced. In this method, quantization scale is limited within a predefined range to keep picture quality. Using the total bitrate and transition of a virtually estimated decoder buffer that is updated by average bitrate, the quantization-scale range is controlled nonlinearly. A frame-based motion evaluation technique is used for scene-change detection and flash-detection to assign VOP (video object plane) coding types to improve random access capabilities and to increase coding efficiency. As a result, high-quality and real-time encoding of SDTV resolution is achieved at the bitrate of 2Mbps.