Image data encoding method and apparatus

An image encoding apparatus, comprising:

• a first processing unit receiving a block of input data of an image, performing thereon an operation comprising one of a two-dimensional orthogonal transformation and a linear quantization to produce and output a first block of output data;
• a storage unit comprising a first memory area and a second memory area, said storage unit receiving the first block of output data into one of the memory areas, and contemporaneously and in parallel outputting from the other memory area a second block of output data of the image, where the second block of output data was processed with the same operation used to produce the first block of output data, and where the memory areas alternate between receiving and outputting;
• and
• a second processing unit receiving the second block of output data and performing thereon one of a linear quantization and a variable length encoding operation.

An image encoding method, comprising:

• performing on a block of input data of an image a first operation comprising one of a two-dimensional orthogonal transformation and a linear quantization to produce and output a first block of output data of the image;
• receiving into one of a first memory area and a second memory area the first block of output data and contemporaneously and in parallel therewith outputting from the other memory area a second block of output data of the image that was generated with the same first operation used to produce the first block of output data, where the memory areas alternate between the receiving and the outputting;
• and
• receiving the second block of output data and performing thereon a second operation comprising one of a linear quantization and a variable length encoding operation.

An image encoding method, comprising:

• storing a first block of original image data into one of a first memory area and a second memory area and contemporaneously and in parallel therewith outputting a second block of original image data from the other first and second memory areas, each of the first and second blocks comprising N2 picture elements of an original image, where N is an integer greater than 1, and where the first and second memory areas alternate between the storing and the outputting;
• orthogonally transforming the output second block of original image data, to produce and output a first orthogonal transform coefficient block;
• storing the output first block of orthogonal transform coefficients into one of a third memory area and a fourth memory area, and contemporaneously and in parallel therewith outputting from the other of the third and fourth memory areas a second block of orthogonal transform coefficients produced by said orthogonally transforming, where the third and fourth memory areas alternate between the storing and the outputting;
• linearly quantizing the second block of orthogonal transform coefficients to produce and output a first block of quantized coefficients;
• storing the first block of quantized coefficients into one of a fifth memory and a sixth memory area, and contemporaneously and in parallel therewith outputting from the other of the fifth and sixth memory areas a second block of quantized coefficients produced by said linearly quantizing, where the fifth and sixth memory areas alternate between the storing and the outputting;
• and
• encoding the second block of output quantized coefficients produced by said linearly quantizing.