| 摘要 |
PURPOSE: An apparatus for controlling a bit rate of an MPEG(Motion Picture Expert Group) encoder is provided to improve a compression rate of a motion picture by using PSNR(Peak Signal to Noise Ratio) information to control a bit rate. CONSTITUTION: A motion estimation and compensation portion(17) extracts a motion vector and obtains a predicting value of a macro block of an input picture. A subtracter(10) calculates a difference value between the predicted block and an input picture block. A DCT portion(11) converts the difference value by DCT. A quantization portion(12) quantizes the converted data. A variable length coding portion(13) codes the quantized data. An inverse quantization portion(15) quantizes inversely the coded data. A bit rate control portion(14) controls an output of the quantization portion. A PSNR calculation portion(18) compares PSNR of each picture to each other. |
