即時視訊在無線網路上的傳輸，基於應用上的需要與狀況的變動性質，可調式音視訊編碼可提供可隨網路情況不同之變動性位元率的視訊資料，並在異質無線網路架構下，讓使用者選擇適合於各項無線行動裝置所支援的視訊服務與應用。然而對於大多數無線行動裝置來說，電源消耗往往是必須考量的重點之一，因此在無線網路上欲達成令人滿意的視訊服務品質，必須同時考量多媒體處理在既定的系統負荷量下，所能提供的位元率與品質，因此無論是編碼端或解碼端的系統運算複雜度，皆是重要的議題。此外並發展降取樣視訊編碼技術，作為可調式視訊編碼之另一方案。在位元率與解析度限制的情況下，使視訊品質仍能獲得保證。本計畫針對我們已發展之可調式音視訊編碼系統，研究其複雜度控制方法，期能提供有效率的音視訊編碼機制，並節省或控制能源消耗。本計畫主要分為三大部分：第一部份研究時間降取樣視訊編碼系統與降取樣系統架構之編碼複雜度控制議題。第二部分將發展H.264/AVC視訊解碼器之複雜度控制機制。第三部分研究低複雜度之可調式音訊編碼。研究完成之後，將會與其它子計畫整合以展示本系統的整體效果，相關成果並將發表於知名國際會議及期刊。For real-time service over heterogeneous wireless networks, the scalable video and audio coding can provide variable bitrate bit streams with different frame rates, resolutions and media quality based on various channel bandwidth conditions. However, the computational complexity and power consumption of audio and video codec are critical under wireless environments. Thus, computational complexity control is necessary to audio and video codec in this scenario. Alternatively, down-sampling video coding technique is supposed to be another scalable scheme that can be combined with video compression technique to improve coding efficiency. This project is aimed to develop complexity control mechanisms for our proposed scalable video and audio coding system. It can provide not only efficient coding scheme to improve the quality of delivered multimedia but also save or control the system power consumption. This project consists of three major parts. The first part is to develop a frame rate down-sampling coding scheme and the complexity control of down-sampling coding system. The second part will develop a complexity control mechanism for H.264/AVC decoder. Finally, the third part will work on the low complexity scalable audio coding. The outcomes of this project will be integrated with other projects to run on a heterogeneous wireless networks platform. 研究期間：10008 ~ 10107
