Study and Optimization of the Deblocking Filter in H.265 and its Advantages over H.264/AVC

H.265 or High Efficiency Video Coding (HEVC) has been developed with a goal to achieve significant compression relative to existing standards in the range of 50% bit rate reduction for the same perceptual video quality [1]. HEVC has been designed to address nearly all existing applications of H.264/AVC and additionally to focus on two key issues: (a) increased video resolution and (b) increased use of parallel processing architectures. The significant reduction in the bit rate comes at the cost of increased coding algorithm complexity and hence increased processing time and higher hardware cost [1]. The objective of this project is twofold: (a) to study the working of in-loop deblocking filter and propose the modification which can improve the performance of HEVC codec and (b) to compare HEVC codec performance with its predecessor H.264/AVC. 1. HEVC Coding Design The HEVC standard is designed to achieve multiple goals, including coding efficiency, ease of transport system integration and data loss resilience, as well as implement parallel processing architectures. In order to implement the parallel processing one needs to understand the HEVC design and capability thoroughly [1]. The following subsection describes the key elements of picture partitioning which is the most powerful technique compared to its predecessors and at the same time most complex and time consuming. a) Video Coding Layer The video coding layer of HEVC employs the same hybrid approach of inter-/intrapicture prediction and 2-D transform coding which are also used in all video compression standards since H.261. Figure 1 depicts the block diagram of a hybrid video encoder which could create the output bitstream for HEVC standard [1]. In order to generate the bitstream the picture is first split into block shaped regions, with the exact block partitioning being conveyed to the decoder.