Scrambling apparatus and descrambling apparatus

A scrambling system comprising a scrambling apparatus for scrambling a compression-coded digital video signal to output a scrambled digital video signal and a descrambling apparatus for descrambling the scrambled digital video signal to output the compression-coded digital video signal,

• said scrambling apparatus comprising:
• detecting means for detecting a predetermined position in said compression-coded digital video signal;
• dummy generation means for generating a dummy data which does not form an original part of said compression-coded digital video signal;
• and
• insertion means for inserting said dummy data at said predetermined position in said compression-coded digital video signal to obtain said scrambled digital video signal;
• and
• said descrambling apparatus comprising:
• dummy detection means for detecting said dummy data in said scrambled digital video signal;
• and
• removing means for removing the detected dummy data from said scrambled digital video signal to obtain said compression-coded digital video signal.

In a scrambling system comprising a scrambling apparatus for scrambling a compression-coded digital video signal to output a scrambled digital video signal and a descrambling apparatus for descrambling the scrambled digital video signal to output the compression-coded digital video signal, said scrambling apparatus comprising:

• detecting means for detecting a predetermined position in said compression-coded digital video signal;
• dummy generation means for generating a dummy data which does not form an original part of said compression-coded digital video signal;
• and
• insertion means for inserting said dummy data at said predetermined position in said compression-coded digital video signal to obtain said scrambled digital video signal.

A descrambling apparatus for descrambling a scrambled digital video signal obtained scrambling a compressed video signal conforming to the MPEG standard having various codes, said descrambling apparatus comprising:

• detecting means for denoting said various codes contained in said scrambled digital video signal;
• reproducing means for reproducing said compressed video signal;
• dummy detection means for detecting a dummy quantization matrix code inserted in said compression video signal;
• and
• means for inhibiting processing of said scrambled digital signal when said scrambled digital video signal matches said dummy quantization matrix code.

A scrambling system comprising a scrambling apparatus for scrambling a compression-coded digital video signal to output a scrambled digital video signal and a descrambling apparatus for descrambling the scrambled digital video signal to output the compression-coded digital video signal,

• said scrambling apparatus comprising:
• detecting means for detecting in said compression-coded digital video signal a predetermined code selected from a group of a first code identifying which one of a field processing and a frame processing is used in an orthogonal transform coded video signal, a second code identifying a coefficient of a DC component in the coefficient components after orthogonal transform coding in the orthogonal transform coded video data, and a third code identifying a scanning method when a DCT coefficient is coded by two-dimensional Huffman coding;
• and
• inversion means for inverting said detected predetermined code in said compression-coded video signal to obtain said scrambled digital video signal;
• and
• said descrambling apparatus comprising:
• detection means for detecting said inverted predetermined code in said scrambled digital video signal;
• and
• means for restoring said inverted predetermined code back to an original non-inverted state to obtain the compression-coded digital video signal.