Software Controller Implementation Of AVS Decoder Based On OpenRISC 1200

With the purpose of promoting the development of national audio and video industries, China set up "Audio and Video Coding Standard Workgroup" in June, 2002. Joint with enterprises and scientific research institutions, it was authorized to establish national audio and video coding standard. Audio Video coding Standard(AVS), independently developed and owned by China, is a fundamental standard in digital TV, IPTV and other audio/video based systems. In March of 2006, the second part of AVS standard (AVS-P2) was officially published. It defines the highly efficient second generation video coding technology. It has coding performance close to H.264. Moreover, it is simple and easy to implement the AVS. AVS has many advantages for us, such as low patent expenses, high data compression ratio and excellent compatibility.SOC is a complex integrated circuit that is based on the IP module reuse technology, which employs embedded system as the core and integrates the whole system into a single or a few chips to complete the entire system function. Owing to the complexity of AVS decoding, it is better to apply software and hardware combining way (SOC) in video decoding to achieve real-time playing requirements of the HD video. In this way, it can save the cost with better flexibility and easier to realize.This thesis focuses on the research and design of the software controller of AVS decoder. Firstly, this thesis illustrates the reason why we choose OR1200 software processor as the controller of AVS decoder. Then, the thesis studies the structure and the instruction set of OR1200 and introduces the Wishbone bus that the decoder uses. Next, based on the research of AVS key technology, this thesis analyzes the complexity of the task of AVS video decoder software, classifies the software task and hardware task, puts forward the architecture of AVS video decoder and defines interface between the various hardware modules. Thirdly, we design the software controller in details, including code stream parsing procedure, reference/display frame updating, interrupt handling and synchronously control etc. At last, we use software platform and hardware platform to verify the software control program. The verification results prove the program correct, meeting the design requirements.