| 摘要 |
<p>PURPOSE:To improve quantization accuracy with respect to an input digital signal by applying quantization of a discrete cosine transformation DCT coefficient in a quantization stage decided by a main quantization step controller provided in a feedforward system and applying real time processing. CONSTITUTION:After a digital video signal is converted into a DCT coefficient at a DCT transformation circuit 12, the result is fed to an operation transformation circuit 21, from which the coefficient is read in zigzag pattern. The DCT coefficient is subjected to a predetermined delay by a delay circuit 22 and the result is fed to a quantization circuit 13 and it is quantized by a main quantization step controller 30. The data are compressed by a variable length coding circuit 14 and variable length coding processing is executed. The coding data are stored in a buffer memory 15 and smoothed. Since some processing time is required to calculate a quantization step by a quantization circuit 13, the delay circuit 1 22 is provided on a pre-stage of the circuit 13. Thus, real time processing is attained for the input digital video signal.</p> |
