JP2002076907A5

JP2002076907A5 -

Info

Publication number: JP2002076907A5
Application number: JP2000263670A
Authority: JP
Filing date: 2000-08-31
Publication date: 2005-10-20
Anticipated expiration: 2020-08-31

Claims

A decoding method of variable-length encoded data that is decoded using a decoding table in which variable-length encoded data and decoded data are associated with each other,
When the maximum code length of the variable-length encoded data is n bits (n is a positive integer), the division position is set in the first to nth predetermined bit positions of the n-bit code, and the set Decoding of the variable length encoded data is generated by generating a decoding table composed of code groups of the number of bits after being divided at the dividing position and sequentially referring to the generated decoding table. A method for decoding variable-length encoded data, characterized in that:

The division position is set to a bit position with a small number of bit inversions by checking bit inversion of each variable-length encoded data for each of the first to n-th bit positions of the n-bit code. Item 4. A method for decoding variable-length encoded data according to Item 1.

The division positions are set at a plurality of places where the number of bit inversions is small, the plurality of places are set as division candidate positions, a plurality of divisions are performed using at least one of the division candidate positions, and the plurality of divisions are performed. At the same time, a plurality of decoding tables are tried to be generated, the total decoding table size of the plurality of decoding tables generated for each of the plurality of divisions is obtained, and the decoding table reference count in the actual decoding process is obtained. 3. The variable length encoded data decoding method according to claim 2, wherein at least one of the plurality of division candidate positions is selected as a division position that is actually divided based on a value.

When the first to mth decoding tables (m is a positive integer) are generated by dividing at the position set as the dividing position, the first to mth decoding is performed. When decoding using the table, the decoding is attempted with reference to the first decoding table. If decoding is possible, the first decoding table is used for decoding, and the first decoding table is used. If decoding cannot be performed with the first decoding table, the first to mth decoding is performed from the first as necessary, such as referring to the next decoding table indicated by the first decoding table. 4. The method of decoding variable length encoded data according to claim 1, wherein the decoding table is selected and performed.

A decoding apparatus for variable-length encoded data for decoding using a decoding table in which variable-length encoded data and decoded data are associated with each other,
When the maximum code length of the variable-length encoded data is n bits (n is a positive integer), the division position is set in the first to nth predetermined bit positions of the n-bit code, and the set Decoding table generating means for generating a decoding table composed of a code group of the number of bits after being divided at the dividing position;
Decoding processing means for decoding the variable-length encoded data by referring to the generated decoding table according to a chain from the first decoding table;
An apparatus for decoding variable-length encoded data, comprising:

In addition to the decoding table generating means and the decoding processing means, it has a sign bit inversion measuring means, and the sign bit inversion measuring means has each variable length code for each first to nth bit position of the n-bit code. Check the bit inversion of the digitized data and obtain a bit position with a small number of bit inversions, and the decoding table generation means uses a plurality of bit positions obtained by the sign bit inversion measurement means with a small number of bit inversions as division positions 6. The decoding apparatus for variable length encoded data according to claim 5, wherein the decoding table is generated.

The division positions are set at a plurality of places where the number of bit inversions is small, the plurality of places are set as division candidate positions, a plurality of divisions are performed using at least one of the division candidate positions, and the plurality of divisions are performed. At the same time, a plurality of decoding tables are tried to be generated, the total decoding table size of the plurality of decoding tables generated for each of the plurality of divisions is obtained, and the decoding table reference count in the actual decoding process is obtained. 7. The variable length encoded data decoding apparatus according to claim 6, wherein at least one of the plurality of division candidate positions is selected as a division position that is actually divided based on a value.

When the first to mth decoding tables (m is a positive integer) are generated by dividing at the position set as the dividing position, the first to mth decoding is performed. When decoding using the table, the decoding is attempted with reference to the first decoding table. If decoding is possible, the first decoding table is used for decoding, and the first decoding table is used. If decoding cannot be performed with the first decoding table, the first to mth decoding is performed from the first as necessary, such as referring to the next decoding table indicated by the first decoding table. The decoding apparatus for variable length encoded data according to any one of claims 5 to 7, wherein the decoding table is selected and sequentially performed.

A recording medium on which a decoding processing program of variable-length encoded data to be decoded using a decoding table in which variable-length encoded data and decoded data are associated is recorded, and the variable-length encoded data The decryption processing program of
A procedure for setting a division position at the first to nth predetermined bit positions of the n-bit code when the maximum code length of the variable-length encoded data is n bits (n is a positive integer);
A procedure for generating a decoding table composed of a code group of the number of bits after being divided at the set division position, and more than the number of divisions;
A procedure for decoding the variable length encoded data by sequentially referring to the generated decoding table;
The recording medium which recorded the decoding processing program of the variable-length coding data characterized by including these.

The division position is set to a bit position with a small number of bit inversions by checking the bit inversion of each variable length encoded data for each of the 1st to nth bit positions of the n-bit code. A recording medium on which the decoding program for variable-length encoded data according to claim 9 is recorded.

The division positions are set at a plurality of places where the number of bit inversions is small, the plurality of places are set as division candidate positions, a plurality of divisions are performed using at least one of the division candidate positions, and the plurality of divisions are performed. At the same time, a plurality of decoding tables are tried to be generated, the total decoding table size of the plurality of decoding tables generated for each of the plurality of divisions is obtained, and the decoding table reference count in the actual decoding process is obtained. 11. The recording in which the variable length encoded data decoding processing program is recorded according to claim 10, wherein at least one of the plurality of division candidate positions is selected as a division position that is actually divided based on a value. Medium.

When the first to mth decoding tables (m is a positive integer) are generated by dividing at the position set as the dividing position, the first to mth decoding is performed. When decoding using the table, the decoding is attempted with reference to the first decoding table. If decoding is possible, the first decoding table is used for decoding, and the first decoding table is used. If decoding with the first decoding table is not possible, the first to m-th decoding is performed as necessary, such as referring to the next decoding table indicated by the first decoding table. 12. The recording medium on which the decoding processing program for variable-length encoded data according to claim 9 is recorded, wherein the decoding table is selected and sequentially performed.