| 摘要 |
PURPOSE:To give a CPU such a margin that another kind of control is performed by calculating one-line code data every time the code data is transferred to an FIFO buffer and reducing the frequency of calculation per line. CONSTITUTION:The CPU 1 reads the contents of the line memory of an RAM 3 firstly to detect the black-and-white run length of each picture signal, and detects code data by referring to the code data table in an ROM 2 on the basis of the run length and also detects the length N2 of the code data at the same time (processing 12). A variable N3 in a register which indicates the remaining number of bits is set to 8 in the beginning of line-by-line code conversion and decreased every time processing 13 is performed. When this variable N3 becomes 0, the result of a judgement 14 is YES, and the CPU 1 transfers 8-bit data stored in the register to the FIFO buffer (processing 15). Then, the variable N1 is increased by eight every time this buffer transfer is performed, and the amount of transfer data on the line is added to the variable N1 (processing 30). |
