1. BIN LI, HOUQIAN LI, LI LI, AND JINLEI ZHANG IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL.23, NO.9, SEPTEMBER 2014 1

2. Overview 2

3. Introduction 3

4. Two steps of rate control : ◦1. Allocate proper number of bits to each coding level (GOP, picture, basic unit, etc.) ◦2. Achieve the pre-allocated bits for each level. E.g., with other parameter fixed(mode, motion, etc.), larger QP generally leads to smaller bit-rate. 4

5. Introduction Step1Step2 5

6. Introduction 6

7. 7

8. 8

9. Reference [4] K.-P. Lim, G. Sullivan, and T. Wiegand, Text Description of Joint Model Reference Encoding Methods and Decoding Concealment Methods, document Rec. JVT-N046, Hong Kong, China, Jan. 2005. [10] Z. He, Y. K. Kim, and S. K. Mitra, “Low-delay rate control for DCT video coding via ρ-domain source modeling,” IEEE Trans. Circuits Syst. Video Technol., vol. 11, no. 8, pp. 928–940, Aug. 2001. [11] M. Liu, Y. Guo, H. Li, and C. W. Chen, “Low-complexity rate control based on ρ-domain model for scalable video coding,” in Proc. 17 th IEEE Int. Conf. Image Process. (ICIP), Sep. 2010, pp. 1277–1280. [16] S. Ma, W. Gao, and Y. Lu, “Rate-distortion analysis for H.264/AVC video coding and its application to rate control,” IEEE Trans. Circuits Syst. Video Technol., vol. 15, no. 12, pp. 1533–1544, Dec. 2005. [18] Y. Liu, Z. G. Li, and Y. C. Soh, “A novel rate control scheme for low delay video communication of H.264/AVC standard,” IEEE Trans. Circuits Syst. Video Technol., vol. 17, no. 1, pp. 68–78, Jan. 2007. [19] H. Wang and S. Kwong, “Rate-distortion optimization of rate control for H.264 with adaptive initial quantization parameter determination,” IEEE Trans. Circuits Syst. Video Technol., vol. 18, no. 1, pp. 140–144, Jan. 2008. [20] S. Hu, H. Wang, and S. Kwong, “Adaptive quantization-parameter clip scheme for smooth quality in H.264/AVC,” IEEE Trans. Image Process., vol. 21, no. 4, pp. 1911–1919, Apr. 2012. [21] Z. He and S. K. Mitra, “Optimum bit allocation and accurate rate control for video coding via ρ-domain source modeling,” IEEE Trans. Circuits Syst. Video Technol., vol. 12, no. 10, pp. 840–849, Oct. 2002. [22] Y. Pitrey, Y. Serrand, M. Babel, and O. Deforges, “Rho-domain for low-complexity rate control on MPEG-4 scalable video coding,” in Proc. 10th IEEE Int. Symp. Multimedia, Dec. 2008, pp. 89–96. [23] Y. Pitrey, M. Babel, and O. Deforges, “One-pass bitrate control for MPEG-4 scalable video coding using ρ-domain,” in Proc. IEEE Int. Symp. Broadband Multimedia Syst. Broadcast. (BMSB), May 2009, pp. 1–5. 9

10. Overview 10

11. Several types of R-D model have been proposed to characterize the relationship between R and D. 1.Exponential function [31]: 2.Hyperbolic function [32][33]: 11

12. 12

13. 13

14. Overview 14

15. Rate Control Algorithm 1.Bit allocation ◦For the First Picture ◦For GOP Level ◦For Picture Level ◦For Basic Unit Level 2.Achieve the target bit-rate for a specific unit (Rate Control Coding) 15

16. Bit Allocation 40 16

17. Bit Allocation 17

18. Bit Allocation For basic unit(CTU in HEVC) level : Similar to picture level bit allocation 18

19. Rate Control Coding 19

20. Rate Control Coding Different level may have different parameter Target bit-rate corresponding to different level 20

21. Rate Control Coding 4.2005 13.7122 21

22. Overview 22

23. Experiment Design 23

24. Experimental Results 24

25. Experimental Results 25

26. Experimental Results 26

27. Experimental Results 27

28. Experimental Results 28

29. Experimental Results 29

30. Experimental Results 30

31. Overview 31

32. Conclusion 1.The difference between actual and target bitrate with proposed method is rather small and has a very high control accuracy. 2.Both the R-D performance and subjective quality of proposed method are better than rate control in HM-8.0. 3.While hierarchical bit allocation is disabled, the proposed method can keep almost constant bit for every picture. 32