Variable length coded data processing method and device for performing the same method

A variable length coded data processing method, in which, after a coefficient obtained by an orthogonal transform of an input signal is quantized, a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data such that an occupancy of a buffer of a decoder does neither overflow nor underflow are coupled and output to the buffer of the decoder, comprising the steps of:

• deleting the end code of the first variable length coded data;
• calculating an amount of deleted code of a data amount of a difference value between a value related to the buffer occupancy at a decoding timing of the last compressed portion data of the first variable length coded data and the buffer occupancy at the decoding timing of the first compressed portion of the second variable length coded data when the value related to the buffer occupancy at a decoding timing of the last compressed portion data of the first variable length coded data is smaller than the buffer occupancy at the decoding timing of the first compressed portion of the second variable length coded data;
• deleting a code corresponding to an A.C. component of data described in a predetermined number of compressed portion data including at least the last compressed portion data of the first variable length coded data by the amount of deleted code;
• and
• coupling the second variable length coded data to the first variable length coded data.

A variable length coded data processing method, in which, after a coefficient obtained by an orthogonal transform of an input signal is quantized, a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data such that an occupancy of a buffer of a decoder does neither overflow nor underflow are coupled and output to the buffer of the decoder, comprising the steps of:

• deleting the end code of the first variable length coded data;
• coding data described in a predetermined number of compressed data including at least the last compressed portion data of the first variable length coded data under a condition that a motion vector is 0 and a motion compensated error data is 0 when a value related to the buffer occupancy at a decoding timing of the last compressed portion data of the first variable length coded data is smaller than the buffer occupancy at the decoding timing of the first compressed portion of the second variable length coded data;
• and
• coupling the second variable length coded data to the first variable length coded data.

A variable length coded data processing device in which a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data are coupled and output to a buffer of a decoder, comprising:

• an end code remover for deleting the end code of the first variable length coded data;
• a calculator for calculating an invalid data of a data amount corresponding to a result of comparison of a value related to a buffer occupancy at a decoding timing of a last compressed portion data of the first variable length coded data, the end code thereof being deleted by said end code remover, with a buffer occupancy at a decoding timing of a first compressed portion data of the second variable length coded data;
• an adder for adding the invalid data calculated by said calculator to the last compressed portion data of the first variable length coded data of which the end code is deleted ;
• and
• a connector for coupling the second variable length coded data to the first variable length coded data added with the invalid data from said adder and outputting it to said decoder buffer.

A variable length coded data processing device in which a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data are variable length coded such that an occupancy of a buffer of a decoder does neither overflow nor underflow after a coefficient obtained by an orthogonal transform of an input signal, coupled and output to the buffer of the decoder, comprising:

• a memory circuit for preliminarily storing the buffer occupancy OC of the last compressed portion data of the first variable length coded data at the decoding timing thereof, the amount DB of code of the last compressed portion data, the amount IB of code input to said decoder during a time period from a time at which the last compressed portion data is decoded to a time at which a next compressed portion data is decoded and the buffer occupancy NOC of a first compressed portion data of the second variable length coded data at the decoding timing thereof, as a coding information;
• an end code remover for deleting the end code of the first variable length coded data;
• a calculator for calculating, on the basis of the coding information read out from said memory circuit, a value represented by (OC-DB+IB), comparing the latter value with the buffer occupancy NOC and calculating an amount of delete code as {(OC-DB+IB)-NOC} when NOC>(OC-DB+IB) and 0 when NOC.ltoreq.(OC-DB+IB);
• a code remover for deleting a code corresponding to an A.C. component of data described in a predetermined number of compressed portion data including at least the last compressed portion data of the first variable length coded data derived from said end code remover, by the amount of delete code input from said calculator;
• and
• a connector for coupling the second variable length coded data to the first variable length coded data output from said code remover.

A variable length coded data processing device in which a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data are variable length coded such that an occupancy of a buffer of a decoder does neither overflow nor underflow after a coefficient obtained by an orthogonal transform of an input signal, coupled and output to the buffer of the decoder, comprising:

• a memory circuit for preliminarily storing the buffer occupancy OC of the last compressed portion data of the first variable length coded data at the decoding timing thereof, the amount DB of code of the last compressed portion data, the amount IB of code input to said decoder during a time period from a time at which the last compressed portion data is decoded to a time at which a next compressed portion data is decoded and the buffer occupancy NOC of a first compressed portion data of the second variable length coded data at the decoding timing thereof, as a coding information;
• an end code remover for deleting the end code of the first variable length coded data;
• a calculator for calculating, on the basis of the coding information read out from said memory circuit, a value represented by (OC-DB+IB), comparing the latter value with the buffer occupancy NOC and setting a code transform flag to a predetermined value only when NOC>(OC-DB+IB);
• transform means for coding data described in a predetermined number of compressed portion data including at least the last compressed portion data of the first variable length coded data output from said end code remover under a condition that a motion vector is 0 and a motion compensated error data is 0 when the code transform flag output from said calculator is the predetermined value;
• and
• a connector for coupling the second variable length coded data to the first variable length coded data output from said code remover.