| 摘要 |
<p>A dynamic image decoder wherein an MB (micro-block) buffer (111) absorbs a difference in speed between the reading from an IDCT (inverse discrete cosine transform) circuit (110) and the writing into a reference frame memory (117) in a motion compensation unit, and a buffer (115) for writing into a DRAM adjusts the timing between the reading from, and writing into, the reference frame memory (117). The adder (114) adds an estimated macro-block signal (S10) from the reference frame memory (117) and an output signal (S9) from the MB buffer (111), and writes the result into the buffer (115) for writing into DRAM. The buffer (115) for writing into DRAM holds the data until the reference frame memory (117) is ready for being written, and then writes the data into the reference frame memory (117). This permits an inexpensive DRAM to be used as a reference frame memory. Here, when a speed for reading of the reference frame memory (117) is higher than a speed of the IDCT circuit (110), a bank (116) is provided in the buffer (115) for writing into DRAM. The data input to the bank (116) are read out before a next data arrives. Therefore, at the time when the next block data is input, the buffer (115) is becoming empty. This makes it possible to reduce the memory size necessary for the timing-adjusting buffer and, hence, to reduce the scale of the hardware.</p> |
