2 : HEVC (Young-Ho Seo et al.: H.265/HEVC Video Watermarking Method with High Image Quality) (Regular Paper) 24 1, (JBE Vol. 24, No. 1, January

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1 2: HEVC (Young-Ho Seo et al.: H.265/HEVC Video Watermarking Method with High Image Quality) (Regular Paper) 24 1, (JBE Vol. 24, No. 1, January 2019) ISSN (Online) ISSN (Print) HEVC a), b), a) H.265/HEVC Video Watermarking Method with High Image Quality Young-Ho Seo a), Yong-Seok Lee b), and Dong-Wook Kim a). HEVC Random Access B I P I P I, P, B., B. Abstract In the field of video watermarking, which adds a time axis to the watermarking of the existing still image, it is important to embed a watermark at a level that can claim copyright while minimizing the overall video quality. In this paper, we focus on the fact that B slices refer to blocks of I and P slices in the Random Access compression method of HEVC. Therefore, We propose that watermark is embedded only in I and P slices and extracted in I, P, and B slices. This can minimize the decreases of the overall image quality of the image and protect the copyright of the B slice without directly embedding the watermark. Keyword : HEVC, DWT, Watermark, Blind, Robust a) (Department of Electronic Materials Engineering, Kwangwoon University) b) (Korea Electronics Technology Institute) Corresponding Author : (Dong-Wook Kim) dwkim@kw.ac.kr Tel: ORCID: This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2016R1D1A1B ). Manuscript received September 10, 2018; Revised December 17, 2018; Accepted December 18, (robust) (fragile). Copyright 2016 Korean Institute of Broadcast and Media Engineers. All rights reserved. This is an Open-Access article distributed under the terms of the Creative Commons BY-NC-ND ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited and not altered.

2 (JBE Vol. 24, No. 1, January 2019), [1][2]. 2, [1].. I (slice). I (intra), I B P., [3]... [4]. Gaj I 4x4 (transform block) [5]. I LowDelay GOP4. 1, HEVC.,, (location map). 100, QP16. Alenizi FullHD 1,920 1,080, LowDelay GOP4, 99 QP20 [6] , HEVC All Intra, Low-delay, Random Access, HEVC Random Access B,. B I P. B. HEVC. B B fps(frame per second) I 1 P I P HEVC. HEVC. DWT(discrete wavelet transform), DWT QIM [3].

3 2: HEVC (Young-Ho Seo et al.: H.265/HEVC Video Watermarking Method with High Image Quality), I P Y. CbCr No Original RGB video I or P slice? Yes Convert to YCbCr format Y channel n-level 2DDWT Deciding quantization step size Multiple WM embedding n-level inverse DWT Convert to RGB format Video sequencing Watermarked image 1. Fig. 1. Watermark embedding procedure Watermark data Data scrambling Key I P RGB YCbCr 2 DWT (2DDWT). DWT n. n 2DDWT (S = LL, LH, HL, HH). 2DDWT. QIM. LH, HL, HH LL. (1). if if if (1). (2). for for (2) i,.. DWT (1).,

4 (JBE Vol. 24, No. 1, January 2019) c i ' 3a Sn 1. 2a Sn 0 Watermarked /attacked image -3a Sn -2a Sn a Sn -a Sn 0 1 a 0 Sn 2a Sn 3a Sn c i Convert to YCbCr format Y channel n-level 2DDWT 0 1 -a Sn -2a Sn Deciding size of quantization step Multiple WM extraction 2. Fig. 2. Quantizer to embed watermark bit De-scrambling Single WM formation Key 2 (3). (3) i,. if if if if if if 2DDWT ,. B I P. Extracted WM 3. Fig. 3. Watermark extraction procedure 3. RGB YCbCr 2DDWT., 2DDWT. (2).,. n 2DDWT i (4). mod 16...

5 2: HEVC (Young-Ho Seo et al.: H.265/HEVC Video Watermarking Method with High Image Quality) III.. C/C++, PC Intel Core i7-2700k 3.50GHz, 16GB RAM, 64 Windows 7 Ultimate K. JCT [7] Table 1. Parameter values for each subband Subband LL LH HL HH ,, 2DDWT n (1). 4. Fig. 4. Watermark data 2. PSNR, NCC. 43dB.,. 2DDWT. 40/100 JPEG, 5 5,,, 3% : (PSNR[dB]) NCC Table 2. Experimental results for each kind of images: image quality after watermark embedding (PSNR[dB]) and NCC value of extracted watermark Attacks Robustness PSNR NCC Only watermarked JPEG quality to Gaussian noise Salt&pepper noise 1% Median filtering Average filtering Gaussian filtering Sharpening Histogram equalization Contrast (-20) Scaling to Cropping 25% Rotation Rotation (unrestored) Average

6 102 방송공학회논문지 제24권 제1호, 2019년 1월 (JBE Vol. 24, No. 1, January 2019) 공격에 사용된 영상은 Full HD(1,920 1,080) 해 상도의 500 프레임 50fps 영상을 이용하여 실험하였다. 50fps영상의 intra period는 48이다. I 및 P 프레임에만 워터 마크를 삽입하고 QP22, 27, 32 및 37로 인코딩과 디코딩을 거친 영상에서 워터마크를 추출하였다. 그림 5에 워터마크 를 삽입한 이후에 HEVC 인코딩과 디코딩을 거친 결과 영 상을 나타냈다. 앞서 설명한 것과 같이 HEVC의 low-delay 모드로 압축할 경우에 I 슬라이스에만 워터마크 데이터를 삽입하였다. 하지만 I 슬라이스 뿐만 아니라 P 슬라이스에 서도 워터마크를 추출하였다. HEVC (a) (b) (a) (b) (c) (d) (e) (f) 그림 6. 워터마크가 삽입된 이후에 (QP=22, HEVC 인코딩) HEVC 디코딩 결과 영상 (a) 0, (b) 2, (c) 4, (d) 6, (e) 8, (f) 10번째 프레임 Fig. 6. HEVC decoding result after watermark embedding (QP=22, HEVC Encoding) (a) 0th, (b) 2nd, (c) 4th, (d) 6th, (e) 8th, (f) 10th frame (c) (d) 표 3. HEVC 압축 공격에 대한 PSNR 결과 Table 3. PSNR results for HEVC compression attack QP (e) (f) 그림 5. 워터마크가 삽입된 후에 HEVC 공격 결과 (a) 원본, (b) QP=1, (c) QP=22, (d) QP=27, (e) QP=32, (f) QP=37 Fig. 5. HEVC attack result after watermark embedding (a) original, attacks with (b) QP=1, (c) QP=22, (d) QP=27, (e) QP=32, (f) QP=37 워터마크 삽입한 영상 압축 후 화질 열화 정도를 표 3에 나타내었다. 워터마크를 삽입하지 않은 원본 영상의 압축 후 화질 열화정도는 QP별로 인코딩 디코딩한 영상을 압축 하지 않은 영상과 PSNR 수치로 나타내었다. 워터마크 삽 입 후 영상의 압축 후 화질 열화정도는 QP별로 인코딩 디 코딩한 영상을 압축하지 않은 영상과 PSNR 수치로 나타내 었다. 표 3에서 알 수 있듯이 워터마크를 삽입했음에도 압 축 후 화질 저하가 적다는 것을 알 수 있다 Compression Ratio 142:1 428:1 922:1 1817:1 Original PSNR[dB] Watermarked PSNR[dB] 그림 7에서는 한 GOP 내에서 I, P, B 슬라이스 별 워터마 크 추출율을 보여주고 있다. 이는 I와 P슬라이스에만 워터 마크를 삽입 했지만 B슬라이스에서도 워터마크가 검출되 며, QP가 높으면 B슬라이스 검출율이 높을 가능성이 크기 도 하다는 것을 보여준다. 그림 8은 하나의 GOP 내의 9개 프레임을 종합하여 워터 마크를 추출한 결과이다. 이는 각 슬라이스에서 추출된 워 터마크를 통계적으로 종합하여 하나의 워터마크로 만드는 방법으로, 압축률 922:1에 해당하는 QP32에서도 NC값 의 높은 추출율을 보이고 있다. 그림 9에는 추출된 워터마크를 나타냈다.

7 2: HEVC (Young-Ho Seo et al.: H.265/HEVC Video Watermarking Method with High Image Quality) Gaj [5]. Gaj QP QP. Basketball. Gaj 20, 24, 28, QP, HEVC , , , NC. 22, 27, QP, 1, 0.97, NC., 32 QP Gaj. (a) (b) (c) (d) 9. (a) I, (b) B, (c) P, (d) Fig. 9. Example of watermarks extracted from each slice, (a) I slice, (b) B slice, (c) P slice, (d) Statistically summarized final watermark IV. Intra, Random Access..,.. (References) 7. Fig. 7. Ratio of extracted watermark 8. GOP Fig. 8. Extracted final watermark from one GOP group [1] W. M. Chen, C. J. Lai, H. C. Wang, H. C. Chao and C. H. Lo, H.264 video watermarking with secret image sharing, 2009 IEEE International Symposium on Broadband Multimedia Systems and Broadcasting, Bilbao, Spain, pp.1-7, 2009, doi: /isbmsb [2] M. Fallahpour, S. Shirmohammadi, M. Semsarzadeh and J. Zhao, Tampering Detection in Compressed Digital Video Using Watermarking, IEEE Transactions on Instrumentation and Measurement, Vol.63, No.5, pp , May 2014, doi: /tim [3] K. Ogawa and G. Ohtake, Watermarking for HEVC/H.265 Stream, 2015 IEEE International Conference on Consumer Electronics (ICCE), Las Vegas, USA, pp , 2015, doi: /icce [4] D-W. Kim, Y-G.Choi, H-S. Kim, J-S. Yoo, H-J. Choi and Y-H. Seo, "The problems in digital watermarking into intra-frames of H.264/ AVC", Image and Vision Computing, Vol.28, No.8, pp , May. 2010, [5] S. Gaj and P. K. Bora, A robust watermarking scheme against re-compression attack for H.265/HEVC, IEEE 5th National Conference on Computer Vision, Pattern Recognition, Image Processing and Graphics (NCVPRIPG), Patna, India, pp.1-4, Dec. 2015, doi: / NCVPRIPG

8 (JBE Vol. 24, No. 1, January 2019) [6] F. Alenizi, F. Kurdahi, A. Eltawil, and A. Aljumah, DWT-based watermarking technique for video authentication, 2015 IEEE International Conference on Electronics, Circuits, and Systems (ICECS), Cariro, Egypt, pp.41-44, Dec. 2015, doi: /icecs [7] Vidio set of JCT, (accessed Jan. 15, 2019) : () : () : () ~ : ~ : - ORCID : - :, 2D/3D,, SoC : () : () ~ : (KETI) - :. 2D/3D : () : : Georgia () ~ : - ORCID : - : 3D,, VLSI Testability, VLSI CAD, DSP, Wireless Communication