Video watermarking apparatus in compression domain and method using the same

A video watermarking apparatus in a compression region and its method are provided to extract an inserted watermark accurately from a monotonic portion of a space region of an image divided into horizontal slices in a compressed region of the image captured through a DVI(Digital Video Interactive) board. An information providing unit(510) provides space region division information obtained by dividing a space region of an image with respect to a compressed video into predetermined horizontal slices. A grouping unit(520) generates a grouped space region by grouping the compressed video based on the space region division information. An extract region selecting unit(530) selects an extract region for extracting a watermark from the grouped space region. A watermark extracting unit(540) extracts watermark bits inserted in a space region of the image excluding a predetermined number of upper and lower slices from the extract region.