Modulation system

A modulation apparatus comprising:

• means for generating a 6-bit output code word in response to every 4-bit input code word by referring to a set of encoding tables, wherein the encoding tables contain output code words assigned to input code words, and contain encoding-table designation information accompanying each output code word, wherein the encoding-table designation information designates an encoding table among the encoding tables which is used next to generate an output code word immediately following the output code word accompanied with the encoding-table designation information;
• means for sequentially connecting the generated output code words into a sequence which follows run length limiting rules;
• and
• means for changing the run length limiting rules between RLL(1, 7) and RLL(1, 8) in response to auxiliary information to superimpose the auxiliary information on the sequence of the generated output code words.

A method of recording auxiliary information, comprising the steps of:

• generating a 6-bit output code word in response to every 4-bit input code word by referring to a set of encoding tables, wherein the encoding tables contain output code words assigned to input code words, and contain encoding-table designation information accompanying each output code word, wherein the encoding-table designation information designates an encoding table among the encoding tables which is used next to generate an output code word immediately following the output code word accompanied with the encoding-table designation information;
• sequentially connecting the generated output code words into a sequence which follows run length limiting rules;
• and
• changing the run length limiting rules between RLL(1, 7) and RLL(1, 8) in response to auxiliary information to superimpose the auxiliary information on the sequence of the generated output code words;
• wherein the auxiliary information contains at least one of 1) an information piece about an encryption key, 2) an information piece being a base of an encryption key, 3) a designating information piece for identifying an encryption key, 4) a designating information piece for identifying a base of an encryption key, 5) an information piece about a region or regions corresponding to one or more countries, one or more zones, or one or more spaces, 6) an information piece about identification of an individual, 7) an information piece about identification of a group of persons, 8) an information piece about a rating, 9) an information piece about identification of an apparatus maker or a device maker, 10) an information piece about identification of a contents provider, 11) an information piece about time, 12) an information piece about contents authors, 13) an information piece about identification of a reproducing apparatus or a reproducing device, 14) an information piece about identification of a connection apparatus or a connection device, 15) an information piece about identification of a medium on which contents information is recorded, 16) an information piece about identification of contents information, 17) an information piece about accounting, 18) an information piece about playback control, 19) an information piece about an address to be accessed, 20) an information piece about recording control, 21) an information piece about a URL address related to contents information, 22) an information piece representing characters, 23) an information piece representing an auxiliary picture, 24) an information piece about audio, 25) an information piece about a copyright, and 26) an information piece about legitimacy of a recording medium storing data.

An apparatus for recording auxiliary information, comprising:

• means for generating a 6-bit output code word in response to every 4-bit input code word by referring to a set of encoding tables, wherein the encoding tables contain output code words assigned to input code words, and contain encoding-table designation information accompanying each output code word, wherein the encoding-table designation information designates an encoding table among the encoding tables which is used next to generate an output code word immediately following the output code word accompanied with the encoding-table designation information;
• means for sequentially connecting the generated output code words into a sequence which follows run length limiting rules;
• and
• means for changing the run length limiting rules between RLL(1, 7) and RLL(1, 8) in response to auxiliary information to superimpose the auxiliary information on the sequence of the generated output code words;
• wherein the auxiliary information contains at least one of 1) an information piece about an encryption key, 2) an information piece being a base of an encryption key, 3) a designating information piece for identifying an encryption key, 4) a designating information piece for identifying a base of an encryption key, 5) an information piece about a region or regions corresponding to one or more countries, one or more zones, or one or more spaces, 6) an information piece about identification of an individual, 7) an information piece about identification of a group of persons, 8) an information piece about a rating, 9) an information piece about identification of an apparatus maker or a device maker, 10) an information piece about identification of a contents provider, 11) an information piece about time, 12) an information piece about contents authors, 13) an information piece about identification of a reproducing apparatus or a reproducing device, 14) an information piece about identification of a connection apparatus or a connection device, 15) an information piece about identification of a medium on which contents information is recorded, 16) an information piece about identification of contents information, 17) an information piece about accounting, 18) an information piece about playback control, 19) an information piece about an address to be accessed, 20) an information piece about recording control, 21) an information piece about a URL address related to contents information, 22) an information piece representing characters, 23) an information piece representing an auxiliary picture, 24) an information piece about audio, 25) an information piece about a copyright, and 26) an information piece about legitimacy of a recording medium storing data.

A modulation apparatus comprising:

• means for generating a final 6-bit output code word in response to every 4-bit input code word by referring to a set of encoding tables, wherein the encoding tables contain output code words assigned to input code words, and contain encoding-table designation information accompanying each output code word, wherein the encoding-table designation information designates an encoding table among the encoding tables which is used next to generate an output code word immediately following the output code word accompanied with the encoding-table designation information;
• means for generating a first candidate current output code word in response to a current input code word equal to one of prescribed input code words by referring to one of first and second specified encoding tables among the encoding tables which is designated by encoding-table designation information accompanying an immediately-preceding final output code word;
• means for generating a second candidate current output code word in response to the current input code word equal to said one of the prescribed input code words by referring to the other of the first and second specified encoding tables under conditions where a succession of the second candidate current output code word and the immediately-preceding final output code word follows a run length limiting rule;
• means for calculating a first DSV from the first candidate current output code word and previous final output code words;
• means for calculating a second DSV from the second candidate current output code word and previous final output code words;
• means for determining which of an absolute value of the first DSV and an absolute value of the second DSV is smaller;
• means for selecting one from the first and second candidate current output code words which corresponds to the smaller DSV absolute value as a final current output code word;
• and
• means for changing the run length limiting rule to change a maximum run length in a sequence of final output code words in response to auxiliary information to superimpose the auxiliary information on the sequence of the final output code words.

A demodulation apparatus comprising:

• means for recovering encoding-state information from a sequence of code words, the encoding-state information representing which of encoding tables has been used in generating a code word immediately following every code word of interest;
• means for demodulating the code word of interest into an original code word by referring to a decoding table in response to the generated encoding-state information;
• means for detecting a frequency of occurrence of a specified run length in the sequence of code words;
• and
• means for reproducing auxiliary information from the sequence of code words in response to the detected occurrence frequency.