Study and Optimization of the Deblocking Filter in H.265 and its Advantages over H.264 By: Valay Shah Under the guidance of: Dr. K. R. Rao

HEVC Overview  HEVC – a buzz word in compression standards  Also known as H.265  50% bit rate reduction compared to H.264 (same picture quality)  Price – more complex video coding algorithm with computationally more expensive tools [2]  HEVC test codec – HM (HEVC test Model) EE-5359 : Project Proposal Presentation2/21/20132

What’s Different?  Picture partitioning – A Coding Tree Block (CTB) of upto 64×64 spatial dimension in HEVC against 16×16 Macro-Block (MB) in H.264 – Minimum size of Coding Unit (CU) in HEVC is 8×8 versus 4×4 in H.264  In-loop deblocking filtering  Sample Adaptive Offset (SAO) filtering  Challenges: – HEVC takes more time (approx. 40%) and hence more power consumption [2] EE-5359 : Project Proposal Presentation2/21/20133

Deblocking Filter (DBF)  Focusing on – Deblocking filter to reduce the processing time  In-loop deblocking filtering in HEVC: – Similar to H.264, operated within inter-prediction loop – Simplified design in regard to its decision making, hence makes it viable for parallel processing  In HEVC the processing order of the deblocking filter is [1] : -Horizontal filtering for vertical edges for the entire picture first -Followed by vertical filtering for horizontal edges EE-5359 : Project Proposal Presentation2/21/20134

Parallel Deblocking EE-5359 : Project Proposal Presentation  Salient Features [2] : - Larger deblocking removes data dependency between the edges in one direction (H.264 uses 4×4 deblocking filter size versus 8×8 used by HEVC) - Hence, the vertical and horizontal filtering could be parallelized fully 2/21/20135

HEVC DBF Procedure [2] EE-5359 : Project Proposal Presentation2/21/20136  Advantages: Allows parallel deblocking  Disadvantages: Increases the processing time since some data needs to be re-fetched

Modified DBF Procedure [2] 2/21/2013EE-5359 : Project Proposal Presentation7  The principle of performing vertical filtering first followed by the horizontal filtering is kept intact  The difference lies in selection of the blocks as shown in the figure on left

Proposed Work  Try to implement modified architecture in HEVC software code to get the performance enhancement  Implement a low complexity offsets perceptual optimization for deblocking filtering [3]  Optimize the skipping mode technique in order to decrease edge processing thereby reducing the power consumption  Compare the HEVC performance with H.264 2/21/2013EE-5359 : Project Proposal Presentation8

Expected Results 2/21/2013EE-5359 : Project Proposal Presentation9

References [1] G. J. Sullivan et al, “Overview of the High Efficiency Video Coding (HEVC) Standard”, IEEE Transactions on Circuits and Systems for Video Technology, vol. 22, no. 12, pp , Dec [2] M. Li et al, “De-blocking Filter Design for HEVC and H.264/AVC/AVC”, PCM 2012, LNCS 7674, pp. 273–284, [3] M. Naccari et al, “Low Complexity Deblocking Filter Perceptual Optimization For The HEVC Codec”, 18th IEEE International Conference on Image Processing, pp , [4] A. Norkin et al, “HEVC Deblocking Filter”, IEEE Transactions on Circuits and Systems for Video Technology, Vol. 22, No. 12, pp , Dec [5] A. J. Honrubia, J. L. Martínez and P. Cuenca, “HEVC: A Review, Trends and Challenges”, Instituto de Investigación en Informática de Albacete, Spain. [6] T. Wiegand et al, “High Efficiency Video Coding (HEVC) Standarization”, IEEE Transactions on Circuits and Systems for Video Technology, Dec [7] C. Man-Yau and S. Wan-Chi, “Computationally-Scalable Motion Estimation Algorithm for H.264/AVC Video Coding”, IEEE Transactions on Consumer Electronics, vol. 56, pp , EE-5359 : Project Proposal Presentation2/21/201310

References-contd. [8] R. Jianfeng, N. Kehtarnavaz, and M. Budagavi, “Computationally Efficient Mode Selection in H.264/AVC Video Coding, IEEE Transactions on Consumer Electronics, vol. 54, pp , [9] Dr. K. R. Rao, “High Efficiency Video Coding”, Chapter 5 – soon to be published. [10] P. List et al, “Adaptive deblocking filter”, IEEE Transactions on Circuits and Systems for Video Technology, vol. 13, pp , [11] K. Xu and C. S. Choy, “A Five-Stage Pipeline, 204 Cycles/MB, Single-Port SRAM-Based Deblocking Filter for H.264/AVC”, IEEE Transactions on Circuits and Systems, vol. 18(3), pp. 363–374, [12] F. Tobajas et al, “An Efficient Double-Filter Hardware Architecture for H.264/AVC De-blocking Filtering”, IEEE Transactions on Consumer Electronics, Vol. 54(1), Feb [13] Y. C. Lin et al, “A Two-Result-Per-Cycle De-Blocking Filter Architecture for QFHD H.264/AVC Decoder”, IEEE Transactions on VLSI Systems, vol. 17(6), June [14] D. Zhou et al, “A 48 Cycles/MB H.264/AVC De-blocking Filter Architecture for Ultra High Definition Applications”, IEICE Transactions Fundamentals E92-A (12), Dec [15] JM software download for H.264/AVC: [16] HM codec download for H.265: 2/21/2013EE-5359 : Project Proposal Presentation11