ENCODER AND ENCODING METHOD

摘要

PROBLEM TO BE SOLVED: To change code quantity of a compressed picture efficiently. SOLUTION: Compressed picture data JPGDI from a code memory 7 are separated into a quantization step value DQT (D), code table information DHT (D) and a variable length code CODE (D). The variable length code CODE (D) is decoded in a run length RRRR (D), a size SSSS (D) and an addition bit ADBIT (D) to write then in a size memory 14. A size transformation part 5f transforms the run length RRRR (M), the size SSSS (M) and addition bit ADBIT (M) each from the size memory 14 based on a frequency domain and the quantity of size transformation each set by size transformation table 5e. The variable length code is allocated to a run length RRRR (C)/size SSSS (C) after conversion. The addition bit is added and a variable length code CODE (E) is generated. The variable length code CODE (E), a quantization step value DQT (E) and a code table information DHT (E) are multiplexed to generate the compressed picture data JPGDO.