Department of Electrical and Computer Engineering, University of California at San Diego, La Jolla, CA 92093-0407, USA.
IEEE Trans Image Process. 2010 May;19(5):1214-23. doi: 10.1109/TIP.2009.2039373. Epub 2009 Dec 28.
Motion scalability is designed to improve the coding efficiency of a scalable video coding framework, especially in the medium to low range of decoding bit rates and spatial resolutions. In order to fully benefit from the superiority of motion scalability, a rate-distortion optimized bitstream extractor, which determines the optimal motion quality layer for any specific decoding scenario, is required. In this paper, the determination process first starts off with a brute force searching algorithm. Although guaranteed by the optimal performance within the search domain, it suffers from high computational complexities. Two properties, i.e., the monotonically nondecreasing property and the unimodal property, are then derived to accurately describe the rate-distortion behavior of motion scalability. Based on these two properties, modified searching algorithms are proposed to reduce the complexity (up to five times faster) and to achieve the global optimality, even for those decoding scenarios outside the search domain.
运动可扩展性旨在提高可扩展视频编码框架的编码效率，特别是在中低解码位率和空间分辨率范围内。为了充分利用运动可扩展性的优势，需要一个速率失真优化的比特流提取器，该提取器确定任何特定解码场景的最佳运动质量层。在本文中，确定过程首先从暴力搜索算法开始。尽管在搜索域内保证了最优性能，但它的计算复杂度很高。然后推导出两个性质，即单调非递减性质和单峰性质，以准确描述运动可扩展性的率失真行为。基于这两个性质，提出了改进的搜索算法来降低复杂度（最高可快五倍）并实现全局最优性，即使对于搜索域之外的那些解码场景也是如此。
