| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent underflow of a buffer memory concerning an image coding method and device. SOLUTION: This device is provided with block dividers 2, 12 and 22 for dividing a digital image signal into blocks, two-dimensional DC transformers 3, 13 and 23 and quantizers 4, 14 and 24 for orthogonally transforming and quantizing the data divided into blocks, and variable length encoders 6, 16 and 26 for outputting the quantized data as a variable length code. Based on the amount of codes generated by the quantizers 4, 14 and 24, a prescribed scale factor is calculated by code amount error integrators 5, 15 and 25 and a scale factor computing element 8 and quantization is controlled by the scale factor. A threshold value discriminator 34 compares the scale factor with a prescribed threshold value and corresponding to the compared result, dummy data generated by a dummy data generator 33 are added to the variable length code. Thus, a multiplexer controller 35 performs control so as to always output data more than a prescribed amount from a multiplexer 27.</p> |
