BIT STREAM DECODING DEVICE

摘要

PROBLEM TO BE SOLVED: To decode a high picture quality image signal during a one-clock period. SOLUTION: A bit stream decoder includes a shifter, variable length and fixed length decoders, a zero-run and AC decoder 330 for receiving the outputs of the shifter and the variable length decoder 320 and calculating zero-run and AC coefficients in the case of an Escape code otherwise calculating the AC coefficient by zero-run and AC levels decoded by the variable decoder 320, a first selector for selecting the output of the variable length and fixed length decoders 320, 325 and the zero-run and AC decoder 330, a second selector for selecting, according to whether Escape AC is generated or not, a variable length decoding size inputted from the decoder, a fixed length decoding size to be inputted from control logic or a bit size to be shifted by the shifter in the case of Escape AC and a first comparator 310 for comparing a prescribed bit string with the selected bit size and for generating a storing part reading signal.