A DWT-based Digital Video Watermarking Scheme with Error Cor(6)

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

2.3. Watermark Embedding

Watermark is then embedded to video frames by changing position of some DWT coefficient with the following condition:

if W[j] = 1,

Exchange C[i] with max(C[i], C[i+1], C[i+2], C[i+3], C[i+4])

else

Exchange C[i] with min(C[i], C[i+1], C[i+2], C[i+3], C[i+4]) (4)

where C[i] is the ith DWT coefficient of a frame, and W[j] is the jth pixel of a certain

watermark [13]. The sequence of watermark coefficients used is stated in Fig. 6.

Fig. 6. Embedding watermarks in a frame. Higher frequency coefficients are embedded to higher frequency part of the video frame. Also, only the middle frequency wavelet coefficient of the frame (middle frequency sub-band) is watermarked [9].

The emphasis of this scheme is the video watermark. The audio watermark is used to help the video watermark and make it more robustness. Namely, the audio watermark is used for refining the video watermark in detection phase, so the error coding code is stored in the audio channel. We have applied a simple audio watermarking technique, the spread spectrum which is proposed in [16], in this scheme.

2.4. Watermark Detection

The watermark is detected through the following process, where overview is shown in

Fig. 7.

Fig. 7. Overview of detection of the watermark