| 摘要 |
<p>PURPOSE:To limit number of quantization bits, to allow picture quality between frames to hardly cause a difference and to improve the transmission efficiency by discriminating a type of an input picture signal. CONSTITUTION:A subtractor 2, a DCT circuit 3, a quantization circuit 4, an inverse quantization circuit 5, an adder 8, a frame memory 10, a motion compensation circuit 9, a loop filter 7, a motion detection circuit 11 quantize a picture signal and a variable length coding circuit 12 implements the variable length coding. In this system, in-frame processing and inter-frame processing are selected adaptively in response to a picture motion of the input picture signal and its output is inputted to a buffer memory 13. In this case, the periodicity of a memory occupancy rate of data in the buffer memory 13 is detected by a periodicity detection circuit 21 and when any periodicity is in existence, a quantization table selection circuit 22 limits a bit number of quantization to be a prescribed value or below.</p> |
