A DWT-based Digital Video Watermarking Scheme with Error Cor(5)

Abstract. In this paper, a digital video watermarking algorithm is proposed. We present a novel DWT-based blind digital video watermarking scheme with scrambled watermark and error correcting code. Our scheme embeds different parts of a single watermark in

used to estimate the pixels within that particular region. The average value of the

pixels in each region is calculated as follows:

(3)

where k is the kth block of the average image, (p, q) is coordinate of region k, (x, y) is the coordinate of the pixel in region k and x × y is the size of a block. A sample is shown in Fig. 4.

(a) (b) (c)

Fig. 4. (a) Original video watermark (b) Visualization of averaging (c) Audio watermark (average of a)

2.2 Video Preprocess

Our watermark scheme is based on 4 levels DWT. All frames in the video are transformed to the wavelet domain. Moreover, scene changes are detected from the

video by applying the histogram difference method on the video stream.

Fig. 5. After scene change detection, watermark m1 is used for the first scene. When there is a scene change, another watermark m3 is used for the next scene.

After scene change detection, as shown in Fig. 5, independent watermarks are embedded in video frames of different scenes. Within a motionless scene, an identical watermark is used for each frame. The watermark for each scene can be chosen with a pseudo-random permutation such that only a legitimate watermark detector can

reassemble the original watermark.