Multimode Embedded Compression Codec Engine for Power-Aware Video Coding System
In a typical portable multimedia system, external access, which is usually dominated by block-based video content, induces more than half of total system power. Embedded compression (EC) effectively reduces external access caused by video content by reducing the data size. In this paper, an algorithm and a hardware architecture of a new type EC codec engine with multiple modes are presented. Lossless mode, and lossy modes with rate control modes and quality control modes are all supported by single algorithm. The proposed four-tree pipelining scheme can reduce 83% latency and 67% buffer size between transform and entropy coding. The proposed EC codec engine can save 62%, 66%, and 77% external access at lossless mode, half-size mode, and quarter-size mode and can be used in various system power conditions. With TSMC 0.18 mum 1P6M CMOS logic process, the proposed EC codec engine can encode or decode CIF 30 frame per second video data and achieve power saving of more than 109 mW. The EC codec engine itself consumes only 2 mW power.