Image coding apparatus and image decoding apparatus
View Patent ↗An image coding apparatus which reduces buffer capacity to a minimum and includes an image coding processing unit which generates intermediate data by executing a part of a process in the coding on the image data; a packetizing unit which generates an image stream by executing a process other than the part of the process in the coding on the intermediate data, such as for example arithmetic coding, and packetizes the generated image stream in synchronization with the image stream generation process.
1. An image coding apparatus which performs coding on image data representing a moving image, said image coding apparatus comprising:
a first coding unit configured to generate first data by executing, on the image data, processing in and before a binarization process performed during the coding of the image data;
a buffer unit configured to temporarily store the generated first data;
a second coding unit configured to generate second data by reading out the first data stored in said buffer unit and executing an arithmetic coding process on the read-out first data; and
a packetizing unit configured to, subsequent to the arithmetic coding process, packetize and output the second data without temporarily recording the generated second data,
wherein said second coding unit is configured to change an amount of the second data to be output to said packetizing unit by changing an amount of the first data to be read out from said buffer unit and an amount of processing on the read-out first data so that a difference between a preset target value and an amount of data which said packetizing unit actually outputs is reduced.
2. The image coding apparatus according to claim 1 ,
wherein said second coding unit is configured to increase the amount of the first data to be read out from said buffer unit and increase the amount of processing on the read-out first data, when the amount of data which said packetizing unit outputs is smaller than the preset target value.
3. The image coding apparatus according to claim 2 ,
wherein an amount of data which said second coding unit reads out from said buffer unit per unit time and an amount of data which said packetizing unit outputs per unit time are substantially the same.