US 2001/0033697 A1 · Variable length coding unit and variable length decoding unit

Abstract

A variable length encoding unit includes a run-length converter, a table memory, and a variable length encoder. The run-length converter converts block data consisting of a plurality of image signals into a zero-run number and a level value in accordance with a scanning sequence. The table memory stores a VLC (variable length code) and VLC length at an address corresponding to the zero-run number and level value. The variable length encoder reads the VLC and the VLC length from the table memory in response to the zero-run number and level value converted by the run-length converter, and carries out the variable length coding by cutting the VLC from the read data in accordance with the VLC length. The variable length coding unit can flexibly handle various types of variable length coding/decoding schemes including international standard coding methods without insisting on its unique variable length coding.

Claims15

Dependent claims

A variable length coding unit comprising:

a run-length converter for converting block data consisting of a plurality of image signals into combined data in accordance with a scanning sequence, each of the combined data including a number of consecutive insignificant coefficients and a value of a significant coefficient next to the consecutive insignificant coefficients;
a table memory for storing a variable length code and its code length corresponding to the combined data at an address corresponding to the combined data;
and
variable length encoder for reading the variable length code and its code length from said table memory in accordance with the combined data converted by said run-length converter, and for carrying out variable length coding of the variable length code by cutting it from the read data in accordance with the code length.

1 more element

A variable length decoding unit comprising:

a bit stream register for storing a received bit stream;
a table memory for storing a code length of each variable length code in connection with combined data including a number of consecutive insignificant coefficients and a value of a significant coefficient next to the consecutive insignificant coefficients in accordance with a scanning sequence of block data consisting of a plurality of image signals;
a data reader for reading a predetermined number of bits from said bit stream register;
an address generator for generating an address of said table memory from data read from said data reader;
and
a variable length decoder for reading data from the address of said table memory generated by said address generator, and for carrying out variable length decoding by cutting from the data the number of the consecutive insignificant coefficients, the value of the significant coefficient and the code length of the variable length code.

3 more elements

Dependencies are inferred from the claim text.

Variable length coding unit and variable length decoding unit

Life of this patent

Variable length coding unit and variable length decoding unit

Life of this patent

Abstract

Claims15