| 摘要 |
PURPOSE:To improve picture quality without increasing a transmission rate or to uniformize picture quality so as to decrease the transmission rate. CONSTITUTION:A luminance signal (Y) supplied to an input terminal 1 is supplied to a block circuit 3 through an A/D converter 2, and is converted into the processing block of 8X8 (picture elements), for example. The signal which is made into a block is supplied to a DCT circuit 4 and a signal which is made into DCT is supplied to a variable length encoding circuit 6 through a quantizing circuit 5. A signal whose variable length is encoded is fetched by an output terminal 7. The signal which is made into DCT from the DCT circuit 4 is supplied to a DC detection circuit 8 and a value Qs corresponding to a detected DC value is supplied to the quantizing circuit 5 and the variable length encoding circuit 6. Thus, the width of steps in quantization in the quantizing circuit 5 is changed. |
