Video scramble/descramble apparatus

A video scramble apparatus comprising:

• a coding unit which subjects a video signal to an inter-picture predictive coding, and outputs first coded video data;
• and
• a scramble unit which scrambles the first coded video data output from said coding unit,
• wherein said scramble unit selects from the first coded video data second coded video data corresponding to a picture, unused as a reference picture for inter-picture prediction in said coding unit, and replaces the selected second coded video data corresponding to slices of the picture in units of m slices which are consecutive in a vertical direction in the picture.

A video scramble apparatus comprising:

• a scramble unit which scrambles a video signal to generate a scrambled video signal;
• and
• a coding unit which subjects the scrambled video signal to interframe predictive coding,
• wherein said scramble unit selects from the video signal a picture unused as a reference picture for inter-picture prediction in said coding unit, said scramble unit dividing macroblocks in a slice of the selected picture in units of m consecutive macroblocks, dividing the m consecutive macroblocks in units of n consecutive macroblocks (n<m), and replacing the n macroblocks in a horizontal direction.

A video scramble apparatus comprising:

• a coding unit which subjects a video signal to inter-picture predictive coding, and outputs first coded video data;
• and
• a scramble unit which scrambles the first coded video data output from said coding unit,
• wherein said scramble unit selects from the first coded video data second coded video data corresponding to a frame unused as a reference picture for inter-picture prediction in said coding unit, dividing macroblocks in a slice of the frame of the selected second coded video data in units of m macroblocks, dividing the m macroblocks in units of n macroblocks (n<m), and replacing the n macroblocks in a horizontal direction.

A video scramble apparatus comprising:

• a scramble unit which scrambles a video signal to output a scrambled video signal;
• and
• a coding unit which subjects the scrambled video signal to inter-picture predictive coding,
• wherein said scramble unit selects from the video picture signal a picture unused as a reference picture for inter-picture prediction in said coding unit, said scramble unit replacing slices of the selected picture in units of p slices which are consecutive in a vertical direction in the picture, and
• said scramble unit divides the macroblocks in units of m consecutive macroblocks, divides the m consecutive macroblocks in units of n consecutive macroblocks (n<m), and replaces the n consecutive macroblocks.

A video scramble apparatus comprising:

• a coding unit which subjects a video signal to inter-picture predictive coding, and outputs first coded video data;
• and
• a scramble unit which scrambles the first coded video data output from said coding unit,
• wherein said scramble unit selects from the first coded video data second coded video data corresponding to a picture unused as a reference picture for inter-picture prediction in said coding unit, and replaces the selected second coded video data in units of p slices of the picture which are consecutive in a vertical direction in the picture, and
• said scramble unit divides macroblocks of each of the slices in units of m macroblocks, divides the m macroblocks in units of n macroblocks (n<m), and replaces the second coded video data corresponding to the n macroblocks.