| 摘要 |
<p>A device for compressing still image data has a discrete cosine transformer (20) for discrete-cosine-transforming video data output in block units from a frame buffer in a digital camcorder, a quantizer (22) for quantizing the video data transformed in the discrete cosine transformer (20), a variable-length coder (24) for variable-length-coding the video data quantized in the quantizer (22), and a quantization interval determiner (26) for producing a quantizer number for controlling a quantization interval, and outputting the quantizer number to the quantizer. The device further has a comparator (28) for comparing the bit number of video data variable-length-coded at quantization intervals for the first frame with a reference bit number for the best image quality, and outputting a flag signal on the basis of the comparison, and a flag buffer (30) for temporally storing the flag signal output from the comparator (28), so that a quantization interval is determined according to the result of the comparison output from the flag buffer (30) to make the bit number of video data of the frames following the first frame approximate to the predetermined reference bit number for the best image quality. Since the bit number of variable-length-coded data of the first frame is compared with its reference bit number, and a quantizer number for the following frame is determined on the basis of the comparison, so that the bit number of the second frame data is approximate to its reference bit number.</p> |
