Storage and read of memory areas and information for decoding

A decoding apparatus, comprising:

• macroblock information storage means including
• a plurality of memory areas each of which stores, as macroblock information, a conditional flag used for generating a context index increment for a corresponding macroblock and is referred to with a horizontal address of the macroblock in a frame, and
• an additional memory area that is located at a left end of the plurality of memory areas and stores a value that indicates invalid macroblock information;
• context index increment generation means for generating the context index increment based on the conditional flags stored in memory areas identified by an address of a macroblock that is to be decoded and an address to an immediate left of that address;
• decoding means for performing a context adaptive binary arithmetic coding decoding process based on a context index calculated based on the context index increment;
• and
• macroblock information update means for generating the conditional flag concerning the macroblock that is to be decoded based on a value obtained as a result of the decoding process, and allowing the generated conditional flag to be stored in the memory area in said macroblock information storage means that is identified by the address of the macroblock that is to be decoded to update the conditional flag.

A decoding method employed in a decoding apparatus that has pixel group information storage means including a plurality of memory areas each of which stores, as pixel group information, information concerning a corresponding pixel group and is referred to with a horizontal address of the pixel group in a frame, and an additional memory area that is located at a left end of the plurality of memory areas and stores a value that indicates invalid pixel group information, the decoding method comprising the steps of:

• a) acquiring the pixel group information stored in memory areas identified by an address of a pixel group that is to be decoded and an address to an immediate left of that address, and generating, as decoding information, information that is necessary for decoding of the pixel group that is to be decoded;
• b) performing a decoding process based on the decoding information;
• and
• c) generating pixel group information concerning the pixel group that is to be decoded based on a value based on the decoding information, and allowing the generated pixel group information to be stored in the memory area in the pixel group information storage means that is identified by the address of the pixel group that is to be decoded to update the pixel group information.

A non-transitory computer-readable medium storing a computer-readable program for causing a computer to execute the following steps, in a decoding apparatus that has pixel group information storage means including a plurality of memory areas each of which stores, as pixel group information, information concerning a corresponding pixel group and is referred to with a horizontal address of the pixel group in a frame, and an additional memory area that is located at a left end of the plurality of memory areas and stores a value that indicates invalid pixel group information:

• a) acquiring the pixel group information stored in memory areas identified by an address of a pixel group that is to be decoded and an address to an immediate left of that address, and generating, as decoding information, information that is necessary for decoding of the pixel group that is to be decoded;
• b) performing a decoding process based on the decoding information;
• and
• c) generating pixel group information concerning the pixel group that is to be decoded based on a value based on the decoding information, and allowing the generated pixel group information to be stored in the memory area in the pixel group information storage means that is identified by the address of the pixel group that is to be decoded to update the pixel group information.

A decoding apparatus, comprising:

• a pixel group information storage section configured to include
• a plurality of memory areas each of which stores, as pixel group information, information concerning a corresponding pixel group and is referred to with a horizontal address of the pixel group in a frame, and
• an additional memory area that is located at a left end of the plurality of memory areas and stores a value that indicates invalid pixel group information;
• a decoding information generation section configured to acquire the pixel group information stored in memory areas identified by an address of a pixel group that is to be decoded and an address to an immediate left of that address, and generate, as decoding information, information that is necessary for decoding of the pixel group that is to be decoded;
• a decoding section configured to perform a decoding process based on the decoding information;
• and
• a pixel group information update section configured to generate pixel group information concerning the pixel group that is to be decoded based on a value based on the decoding information, and allow the generated pixel group information to be stored in the memory area in said pixel group information storage section that is identified by the address of the pixel group that is to be decoded to update the pixel group information.

A decoding apparatus, comprising:

• a macroblock information storage section configured to include
• a plurality of memory areas each of which stores, as macroblock information, a conditional flag used for generating a context index increment for a corresponding macroblock and is referred to with a horizontal address of the macroblock in a frame, and
• an additional memory area that is located at a left end of the plurality of memory areas and stores a value that indicates invalid macroblock information;
• a context index increment generation section configured to generate the context index increment based on the conditional flags stored in memory areas identified by an address of a macroblock that is to be decoded and an address to an immediate left of that address;
• a decoding section configured to perform a context adaptive binary arithmetic coding decoding process based on a context index calculated based on the context index increment;
• and
• a macroblock information update section configured to generate the conditional flag concerning the macroblock that is to be decoded based on a value obtained as a result of the decoding process, and allow the generated conditional flag to be stored in the memory area in said macroblock information storage section that is identified by the address of the macroblock that is to be decoded to update the conditional flag.