# Introduction ith the advent of digital video broadcasting over the internet and DTH (Direct to Home) /DVB (digital video Broadcasting) many issues of copy right protection is of great importance [3] [4]. Since the duplication of digital video signals does not result in the inherent decrease in quality of the suffered analog video signals. Invisible watermarking is one of the solutions for the protection of the digital data. A water mark is a digital code that is embedded in the video sequence which can be used to transmit that video to the copyright owner in others terms this can be used to send the copy of digital data only to the legal user. This allows illegally reproduced copies to be traced back to the receiver from which they are originated. A simple diagram used to depict the scenario. # Figure 1: Block diagram of Copyright protection The digital video watermarking is regarded as a complete cryptogram communication system in which the watermark is regarded as the transmitted message and the video frame as the channel or carrier for the watermark and the pixels that are encountering attacks as the noise in the channel [1]. Based on this concept we can use parity check codes for error correction codes. In this paper we use LDPC codes for error correction. Error correction codes are commonly used to protect memories from so-called soft errors, which change the logical value of memory cells without damaging the circuit. As technology scales, memory devices become larger and more powerful error correction codes are needed. To this end, the use of more advanced codes has been recently proposed. These codes can correct a larger number of errors, but generally require complex decoders. To avoid a high decoding complexity, the use of one step majority logic applications LDPC code was first presented by Gallager [2], these codes have many advantages like stronger ability to correct errors and have the lower error floor, it's a parallel algorithm which is very much suitable for hard ware implementation, lower delay in decoding process, lastly it uses the length of the watermark and the value of the transformed coefficients for adaptive embedding. In [5], XU Ba et al proposed a blind video watermarking algorithm based on LDPC, improving the robustness of video watermarking algorithm in the original domain. In [6], Hsu et al proposed a video watermarking scheme based on DCT, using the DCT coefficients to embed watermark. In [7], Hartung et al proposed a scheme that the watermark is added in the MPEG-4 facial motion parameters. The disadvantage of the method is that extracting the watermarking requires the original host signal and the rate of extracting is unbalance. In [8], Chen Chao et al proposed a video watermarking algorithm in compressed domain, using the intermediate frequency coefficient of the luminance to embed watermark. Also, in [9], Li Jing et al proposed a robust blind video watermarking algorithm, using the lowfrequency coefficient of the luminance component to embed watermark ?? ?? ? = ?? ?? + ?? ?? ?? ?? ?? ?? (1) Where 'i' is the i th Dct coefficient and 'k' is the middle frequency component , ?? ?? is the original DCT coefficient and ?? ?? ? is the modified coefficient , ?? ?? ? {?1,1} is the spreading sequence .the value of ?? ?? is set as If |?? ?? |<2 then ?? ?? = 2 If 2< |?? ?? |<10 then ?? ?? = 2.5 (2) If 10< |?? ?? |<20 then ?? ?? = 3 If |?? ?? |>20 then ?? ?? = 5 Spreading sequences: In this paper three different types of spreading codes were used PN sequence [13], Gold Codes [14] and Walsh/Hadamard codes [15]. # b) Extraction Process ? The watermarked video frame is converted into Ycbcr from which the 'Y' component is selected for the process ? Apply the DCT transform and convolve the middle frequency coefficients with spreading sequence. ?? ?? = ? ?? ?? ? ?? ?? (??+1)?????? ?1 ??=????????(3)???? = 32 ? Consider the sign of the resultant coefficient value and perform LDPC decoding to extract the logo III. # Experimental Results Experiments were conducted using the video sequences from [10] # Conclusion A invisible mode of video watermarking with pre coding and spreading sequences is proposed in this paper , the present approach is compared against three spreading sequences and found that when encoded with LDPC gold sequences of spreading leads to the low bit error and also high visual quality of the video sequence. This work can implemented for all the DVB and internet services where the quality of video is of greater demand. This work can be further extended by implementing this methodology with advanced trans forms like contour let and curve lets. ![Figure 2(a): Embedding process](image-2.png "WE") 23![Figure 2 : Block diagram of embedding and extraction process Original Video: In this paper for the experimental analysis different videos available at [10]. The sample video frames are displayed below](image-3.png "Figure 2 :Figure 3 :") 4![Figure 4: (a) Original Video frame (b) Watermarked frame (c) Original Logo (d) extracted with PN spreading sequence and LDPC coding (e) extracted Without LDPC coding](image-4.png "Figure 4 :") 56![Figure 5 : Performance analysis for mobile video sequence with proposed approach](image-5.png "Figure 5 :Figure 6 :") 78![Figure 7: Mean square Error Analysis of the proposed approach for the Mobile.avi video sequence](image-6.png "Figure 7 :Figure 8 :") 9![Figure 9 : PSNR analysis for different video sequences IV.](image-7.png "Figure 9 :") 1ParameterNO PRE-CODINGLDPCBER0.040.01NC0.990.99PSNR49.2849.31 2 © 2014 Global Journals Inc. (US) © 2014 Global Journals Inc. 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