A Blind and Robust Watermarking Scheme for H.264 Video

8/2/2019 A Blind and Robust Watermarking Scheme for H.264 Video

1/4

A Blind and Robust Watermarking Scheme for H.264 Video

lB Y Lei*, lK T. Lo, Senior Member , and Haijun Lei crnc n nrn nnrn n Kn cnc nrs n Kn

College of Computer Science and Technology, Shnzhn Uniersity, Shenzhen, [email protected]

- H.264/AVC is becoming a popular video codec forits better compression ratio, lower distortion and applicability

to portable electronic devices. Thus, issues of copyright

protection appropriate for this standard become very

important. In this paper, a new blind SVD (Singular ValueDecomposition) - DCT combined video watermarking schemefor the ".264 standard is proposed. The proposed method is ablind watermarking algorithm as the hidden information can beextracted without the original video and the original singular

values. To reduce visual quality degradation caused by

coecients modifying, the perceptual model and block selection

mechanism are introduced to control the modication strength.The performance of the proposed algorithm is evaluated with

respect to imperceptibility, robustness and data payload.Experimental results reveal that the proposed scheme achievesenough robustness while preserving the perceptual quality.

I. INTRODUCTION

One effective solution gaining popularity in protecting

igital contnts for copyright ownrs is igitalwatermarking which embeds the copyright information into

the digital media. H.264/AVC is te latest coding andcompression standard with adanced compression technique,imroed perceptual quality, network iendliness andversatility [1]. As H.264/AVC becomes more pralent, thindustry will need copyright protection metods. Hower,

the large body of PEG series ideo watermarkingalgorithms cannot be aplied irectly to H.264/AVC becausH.264A VC uses different transformation and block sizes;

therefore, devlopment of new and appropriate watermarkingalgorithms for H.264/AVC is requird.

In general, H.264A VC coding standard adopts many newfaturs and can be exploitd for watermarking purpose.Actually, compressed domain watermarking methods arousegrat interests of industris and researches to th intellectual

property protection. A few recently published apers haescusse mbn watrmark n 26VCbitstream sequenc. For examle, in [2], Hartung t al.embeddd the watrmark into the H.264AVC bitstreamdirctly. But this mthod is too complx. The H.264watermarking method proposed in [3] inserte watermarksinto selcte 4x4 CT blocks in intraames. Howeer, thisembedding method neds to send side information forwatermark extraction. In [4], Zhang et al. delope a robustideo watermarking algorithm of H.264AVC with twodifferent watermarks. A binary sequence and grayscale imageaer proposed preprocessing served as watrmark wre

insrted into th integer 4x4 DCT coecient with spradspectrum method which are compatible with H.264AVCstandard and resisted most of the signal processing and otherattacks. esides, Lagrangian optimization was used to selectoptimal mode and a slidwindow are adopted to rtherimprov the performance. In [5], the authors present a blindwatermarking algorithm that embeds th watermark inH.264/AVC Iames. However, it requirs dcomrssingthe ideo in order to embed the watermark. A human isual

modl has ben us in [6] to esign watermarkingalgorithms for PEG2 ido which incrased the payloadand robustness with limited visual distortion.

Recntly, SV is a esirable and powerl transformtchniques xplored for robust watermarking. If SVD isapplied to the cover signal directly, the imerceptibility wasnot guaranteed because small changes in singular alus mayresult in large artifacts aer reverse transformation. SincCT basd technique is one of the most opular transformdomain techniques and adopted in H.264/AVC. Threfore,

our proposed schme combines SVD with DCT to furthertradeoff btween robustnss and imperceptibility. The twotransform domain techniques proide different, but

complementary leels of robustness against the same attack.In fact, thre are some image and ideo watermarkingtechniques based on SVCT in the literature too. ong etal. [7] roose a SVD based blind ideo watrmarkingmthod, but it only showe the desirable robustness proertyagainst MPEG-2 compression instad of the latestH.264A VC attack. In [8], Wang t al. designed a blind robustwatermarking scheme based on SVDDCT, but it only builton H.263 rather than H.264/AVC. One SVDDCT basewatrmarking for PEG2 video is proposed in [9].Insummary, blind watermarking basd on SVCT has notbeen inestigated to be compatible to H.264AVC standard.

The furthr study and instigation are required.Th oal of this aer is to prsent a robust SVD-DCT

watrmarking algorithm for H.264/AVC that is both fast androbust enough for practical applications. The rest of thispaper is organized as follows. SVD watrmarking principl isintroduced in Section II. Watrmark mbedding andextraction are given in Section III and IV respctively.Section V presnts the experimental results. Finally, SectionVI concludes th paper.

II. SVD WATEAING

7-1-4244-8223-81 0/$26.0 2 10 EEE 421


2/4

SVD is a numerical technique for linear algebraic in thetransformed domain consists of basis states that is optimal insome sense. Although SVD works for any x matrix , ourdiscussion will be limited for the x matrix. The SVD ofthe x matrix A is dened as:

A= UVT ()where U and VE RNxN are unitary, and E RNxN is adiagonal matrix and the superscript denotes matrix

transposition. The diagonal elements of are called thesingular alues of and reassumed to be arranged indecreasing order. The columns of the Umatrix are called thele singular ectors while the columns of the V matrix arecalled the right singular ectors of . In SVDbasedwatermarking, a ame is treated as a matrix decomposed intothree matrices.

The watermark carrier w(i,j) is added with a scaling or

strength factor as follows:

Wd(i,)= OJ +abOw(i,j) (2)where OJ are the singular alues of the matrix (diagonal

elements of), bE (0,1) is the polarity of the watermark

sequence to be embedded. w(i,j) represents the random

carrier elements, and a is a strength factor. Beforeembedding, the watermark is also shaped by the originalsingular alue coefcients. We adaptiely scale thewatermark strength with perceptual concerns. The resultingwatermark matrix is subjected to a new SVD operationdenoted as:

WD= Uw wV (3)

Finally, the watermarked message block Awis obtained by

inerse SVD operation.

Aw= UVT (4)

III. ATERMARK MBEDDING

In order to achiee high robustness against commonprocessing operations and H.264 compression attacks, aSVDDCT hybrid domain watermarking scheme is proposedin this paper as shown in Fig..

Warmarkquence

Fig..The proposed H.264 watermarking scheme

The embedding procedure is described in details in thefollowing steps:

Step : Diide the ideo clip into ideo scenes;Step 2: Conert eery ideo frame om RB to YCC

color matrix format;

Step 3: Permute the binary watermark sequence by arandom seed key;

Step 4: Perform SVD on each block to produce singularalues;

Step 5: Diide eery ame of the ideo into a number ofnonoerlapping blocks, each including 4x4 pixels;

Step 6: Concatenate the rst singular alues om adjacent16 blocks to form a 44 SV block;

Step 7: For each SV block, DCT is performed to obtain itscorresponding SVDDC block. The difference betwen themagnitudes of two coecients in a selected pair is rstcomputed as follows:

(xl'Yl'X2'Y2,Zl'Z2)=1 F(xl'Yl'zj)I-IF(X2'Y2,Z2)I (5)where F(xl'Yl'zj) and F(X2'Y2,Z2) are the coordinates of

the selected pair in the SVDDCT block. The case ofembedding a watermark bit " is as follows:

) If: , no operations are needed;2) If < as , perform the following operations:

F(xl'Yl'Zj)=

sign(F(xl'yl'Zj [(F(xl'yj,Zj)+F(X2'Y2,Zz})/ +0.5mask]

F(X2'Y2,Z2)=

sign(F(x2'Y2'Z2.[(F(xl'Yl'Zj)+F(X2'Y2'Z2 -0.5as]

(6)where is the frequency mask for changing thewatermarking strength according to the Human VisualSystem (HVS). For embedding a bit of "0,the embeddingmechanism is the same as embedding "1 with the swap of thepositions of F(xl'Yl'zj)and F(X2'Y2,Z2).

IV. ATERMAK XTCTION

The proposed algorithm is also blind in the sense that itdoes not need the original ideo in the extraction process.Therefore, we can extract the watermark image from thewatermarked ideo ames directly as presented in detail in

the following steps:Step : Diide the watermarked ideo clip into

watermarked scenes;Step 2: Process the watermarked frames of each

watermarked ideo scene using SVD;

Step 3: Conert the ideo frame from RB color matrix toCC

Step 4: Retrieal the positions of the coecients pairsin each SVDDCT block;

Step 5: The difference between coefcients of each

selected pair is computed as:

(xj,x2,Yj'Y2,Zj,z}=1 F(xj,yj,Zj)- F(X2'Y2'Z2)I (7)where F(xl'Yl'Zj)and F(x2, Y2,Z2) are the selected pairs

of coefcients that might be watermarked;Step 6: Sum the alues of different corresponding to all

pairs of coecients where the same bit is repeatedlyembedded:

(8)

422


3/4

Step 7: The extracted bit is judged as follows:

{I ; 0W=

o < (9)

Step 8: Apply inverse SVD on the modied coefcient

matrix and extract the embedded watermark.

V. XPEMENTAL SULTS

The proposed watermarking scheme has been integratedwt t 64/VC JM ec sowa osimulation. The frame rate was 30 ames per second. TheH.264 soware was run on a number of sample videos suchas Mobile, Foreman, Carphone, Container and Suzie in QCIFformat (176144). In our experiments, the watermark is apseudo-random sequence. The rst 25 frames of the videosequences are used in the experiments. We evaluated theperformance of the proposed SVD-DCT video watermarking

algorithm with respect to imperceptibility and robustness.A obustness

In video watermarking application, robustness is usuallymeasured against compression, rotation, Gaussian noise, salt& pepper noise, frame dropping, ame averaging, and frameswapping and other attacks. The similarity between theoriginal and extracted watermarks is evaluated using thecorrelation factor which may take values between 0 and 1.The high correlation value clearly indicates robustness of the

algorithm against major attacks. As shown in table I, thewatermark can still be extracted with a high correlation valueaer various attacks. It also maintained a high degree of

robustness.

LE I WTERRK ROUTNE GINT VRIOU TTK

sequences Mobile Forman Container Suzie

H.264/AVC0.9226 0.8912 0.9078 0.9190

6M bit/s

H.264/AVC0.9128 0.8894 0.8945 0.9030

4M bit/s

Shi 0.8324 0.8065 0.814 0.8235

Medi flter 0.9323 0.8842 0.8832 0.8975

Rotation and0.8 0.013 0.0 0.15

scale

Frme0.8474 0.7941 0.8017 0.8197

droppig

Frme0.8356 0.7825 0.7989 0.8054

averaging

Addig0.9026 0.8464 0.8532 0.8693

Gaussi noise

Adding Sat&0.9134 0.8538 0.8674 0.8757

Pepper noise

It can be derived that robustness of watermarks depends onthe DCT domain watermarking technique. The smallerblock-size of 4 4 integer DCT transform reduces the ringingartifacts to further improve the robustness.

B ImperceptibiliThe PSNR (Peak Signal Noise Ratio) is typically adopted

to judge the visual quality of the embedding watermarkframes. The average PSNR for all watermarked frames was41.18 which mean not much uality deradation in the

watermarked video was perceived. This high PSNR valueproves imperceptibility of the proposed SVD-DCTalgorithm.

Fig.2 presents the results of foreman sequence withwatermark and without watermark respectively. From Fig. 2,it is observed that the watermarks in our scheme cause novisible artifacts to the video picture. In the experiments, no

obvious and visible degradation can be observed in the entiretest vido sequences. The results indicate that our schemealways maintains a higher perceptual quali score. It can beconcluded that transparency of this algorithm is rather good.

(a) (b)Fig.2. The rst ame of foreman with and withoutwatermark; (a) unwatermarked;(b)watermarked

Besides, we compare performance of our SVD-DCTscheme with the pure SVD scheme in [7], as comparisonresults of pure SVD method in not fair enough, we alsocompare our method with the similar SCD-DCT method in

[8], which is also blind method based on SVD-DCTtransform, however, this method is not built on H.264 frame.A higher value indicates that the watermarked video isperceptually closer to the original sequence. Fig.3 shows thePSNR comparison results of the rst 25 frame of Mobilesequence in our method, SVD method in [7] and SVD-DCTmethod in [8]. It can be obviously noted that our schemeoutperform the SVD method in [7] and SVD-DCT method in[8] as our proposed method have a relative high averagePSNR. The reason for your higher PSNR is that we adoptsome enhanced feature to improve the performance anddowngrade the negative effects.

423


4/4

F ts d f 21 d "i

Fig.3. Comparison of PSNR of the rst 25 watermarkedames with pure SVD method in [7] and SVD-DCT methodin [8]

Payload

Data payload or watermarking capacity for a given host

video clip is dened as the number of watermark pixels thatcan be embedded in the host video without causing any visualdistortion in the video. To compare the proposed algorithm interms of payload, suppose that we have a scene with 56ames and an SVD matrix (U, S, V) with a dimension 240 x240. As we adopt the block based SVD-DCT method forwatermark embedding and detection, the payload of ouralgorithm is found by multiplying number of ames bynumber of blocks per frame by number of pixel per frame.Therfor, th pyloa of ou proposd method s 220pixels, which shows our proposed block-based algorithm'spayload is higher enough for some feasible application when

some large watermarks are needed in video watermarking. Complei

For the complexi performance, om the abovedescription, as we adopts some enhance feature and algorithmto enhance the robustness and build on algorithm on the highcomplexity video codec, H.264, therefore, the complexity ofour proposed method is more higher than the SVD method in[7] and SVD-DCT method in [8]. As we know, the highercomplexity means higher time requirement, as a result, thereal-time performance of H.264 will be downgraded.However, in our experiments, even though the realtime issacriced a little bit, H.264 can still achieve realtimeperformance, which indicats the complexity is in the

acceptable level.

VI. CONCLUSION

A novel and hybrid digital video watermarking algorithmof H.264 with combination of two powerful mathematical

transforms DCT and SVD to exploit their attractive featuresis proposed and implemented in this paper. Experimentalresults demonstrated the advantages of our proposed methodare blindness, robustness against compression and simplegeometrical attack. Our algorithm is robust to most attackslike H.264/AVC compression, rescaling, shiing, ltering,etc. In our future work, we will improve the algorithm to

gain better performance against other attacks like big

rotation and cropping by multiwatermark technique.

RFERENCES

[1] "Dra TU-T recommendation and final dra inteational standard ofjoint video specification (TU-T Rec. H.264 SOEC 14496-10 AVC).

Joint Video Team (JVT) of SOEC MPEG and TU-T VCEGJVT-G050," 2003.

[2] F. Harung and B. Girod, "Watermarking of uncompressed andcompressed video," Signal Processing, vol. 66, pp. 283-301, 1998.

[3] N. Maneli and M. M. Russell, "A Framework for Robust Watermarkingof H.264-Encoded Video With Controllable Detection Performance,"IEEE Transactions on Information Forensics and Securi, vo 2, pp.14-23,2007.

[4] 1. Zhang, A T. S. Ho, G. Qiu, and P. Marziliano, "Robust videowatermarking of H.264/AVC," IEEE ransactions on Circuits andSystems I Analog and Digital Signal Processing, vol. 54,pp. 205-209,2007.

[5] W. Guo-Zua, W. Yi-Jung, and H. Wen-Hsing, "Robust watermarkembedding/detection algorithm for H.264 video," Joual of ElectronicImaging, vol. 14, pp. 13013-1,2005.

[6] D. Simitopoulos,S. A. Tsaaris,N. V . Boulgouris,and M. G. Strintzis,

"Compressed-domain video watermarking of MPEG streams," in Proc.of IEEE Inteational Con! on Multimedia and Expo pp.569-72,2002.

[7] W. H. Kong, BYang, D. Wu, and X. M. Niu, "SVD based blindvideo watermarking algorithm," in Proc. of First Inteational Co onInnovative Computing, Iormation and Control pp. 265-268,2006.

[8] H. X. Wang, Z. M. Lu, and S. H. Sun "A blind video watermarkingalgorithm based on SVD in the DCT domain," in Proc. of InteationalElectronic Con! on Computer Sience pp. 360-364,2007.

[9] W. Di, K. Wenhai, Y. Bian, and N. Xiamu, "A fast SVD based videowatermarking algorithm compatible with MPEG2 standard," SoComputing, vol. 13, pp. 375-82,2009.

424

A Blind and Robust Watermarking Scheme for H.264 Video

Documents

Transcript of A Blind and Robust Watermarking Scheme for H.264 Video