| 摘要 |
An apparatus and a method for compressing a picture by wavelet transform and entropy coding, in which the processing load of arithmetic coding may be relieved and rate control may be carried out effectively, while still maintaining the picture quality. An encoding object prediction unit predicts bitplanes to be encoded and extracts only those bitplanes which are to be encoded. An EBCOT unit generates an encoding pass from one bitplane to be encoded to another to execute arithmetic coding. In controlling the code volume to a target code volume, a rate controller sums the arithmetic codes in a sequence from the arithmetic code with the highest bit position in the totality of the code blocks of an input picture to the arithmetic code of the lowermost bit, from one bitplane to another or from one encoding pass to another, and halts the summation when the predetermined target code volume is exceeded.
|
