Non-tables look-up search algorithm for efficient H.264/AVC context-based adaptive variable length coding decoding

• Published in: Journal of electronic imaging Vol. 23; no. 5; p. 053007
• Main Authors: Han, Yishi, Luo, Zhixiao, Wang, Jianhua, Min, Zhixuan, Qin, Xinyu, Sun, Yunlong
• Format: Journal Article
• Language: English
• Published: Society of Photo-Optical Instrumentation Engineers 01.09.2014
• Subjects: H264/AVC; context adaptive variable length coding decoding; variable length coding table; memory access
• ISSN: 1017-9909; 1560-229X
• DOI: 10.1117/1.JEI.23.5.053007

In general, context-based adaptive variable length coding (CAVLC) decoding in H.264/AVC standard requires frequent access to the unstructured variable length coding tables (VLCTs) and significant memory accesses are consumed. Heavy memory accesses will cause high power consumption and time delays, which are serious problems for applications in portable multimedia devices. We propose a method for high-efficiency CAVLC decoding by using a program instead of all the VLCTs. The decoded codeword from VLCTs can be obtained without any table look-up and memory access. The experimental results show that the proposed algorithm achieves 100% memory access saving and 40% decoding time saving without degrading video quality. Additionally, the proposed algorithm shows a better performance compared with conventional CAVLC decoding, such as table look-up by sequential search, table look-up by binary search, Moon's method, and Kim's method.