Patent ID: 8094726
Filing Date: 2012-01-10
Classification: H04N

Abstract:
1. An image encoding apparatus which, defining a region including a plurality of pixels as a block, and a region including a plurality of blocks as a macro block, inputs image data including a plurality of macro blocks, generates encoded data of each macro block by processing the block as a minimum unit, and generates encoded data of the image data by arranging the encoded data of the macro blocks in a preset order, comprising: an input unit which inputs the image data including the plurality of macro blocks; a frequency conversion unit which frequency-converts each block to obtain one DC component data and a plurality of AC component data from each block; a block overlap processing unit which filters data in a region across a boundary between adjacent blocks to suppress discontinuity of data at the boundary; a setting unit which sets one of “0”, “1”, and “2” as an execution count of said block overlap processing unit based on a resolution of the image data of an encoding target; a quantizing unit which quantizes each component data obtained by said frequency conversion unit; an entropy encoding unit which entropy-encodes each component data after quantization by said quantizing unit; and a control unit which executes said frequency conversion unit twice, and executes said block overlap processing unit as many times as the count set by said setting unit, wherein when the execution count set by said setting unit is “0”, said control unit (a) executes said frequency conversion unit a first time to frequency-convert each block in the macro block including the plurality of blocks, thereby calculating a plurality of DC component data of first level and a plurality of AC component data of first level, (b) executes said frequency conversion unit a second time to calculate one DC component data of second level and a plurality of AC component data of second level, while defining the plurality of DC component data of first level as a block, and executes the processes (a) and (b) for the image data including the plurality of macro blocks, when the execution count set by said setting unit is “1”, said control unit (c) executes said block overlap processing unit to execute the block overlap processing for each block in the macro block including the plurality of blocks, (d) executes said frequency conversion unit a first time to frequency-convert each block in the macro block processed by said block overlap processing unit, thereby calculating a plurality of DC component data of first level and a plurality of AC component data of first level, (e) executes said frequency conversion unit a second time to calculate one DC component data of second level and a plurality of AC component data of second level, while setting the plurality of DC component data of first level as a frequency conversion target, and executes the process (c) to (e) for the image data including the plurality of macro blocks, and when the execution count set by said setting unit is “2”, said control unit (f) executes said block overlap processing unit a first time to execute the block overlap processing for each block in the macro block including the plurality of blocks, (g) executes said frequency conversion unit a first time to frequency-convert each block in the macro block processed by said block overlap processing unit the first time, thereby calculating a plurality of DC component data of first level and a plurality of AC component data of first level, (h) executes said block overlap processing unit a second time to execute the block overlap processing for each block including the plurality of DC component data of first level in the image data including the plurality of macro blocks, the plurality of DC component data of first level being obtained by executing said frequency conversion unit of first level, and (i) executes said frequency conversion unit a second time to execute frequency conversion as many times as the number of blocks included in a set of the DC component data of first level obtained by said block overlap processing unit the second time.