A video scramble apparatus has a scrambler for scrambling an input video signal,
and a video encoder for performing interframe predictive coding of the video signal
after scrambling, and the scrambler selects a frame, which is not used as a reference
frame for interframe prediction in the video encoder, from the input video signal,
and scrambles the frame by pixel replacing in units of slices within a predetermined
vertical range or pixel replacing in units of n consecutive macroblocks within
a predetermined horizontal range.
