公开(公告)号：EP1445958A1

公开(公告)日：2004-08-11

申请号：EP03002443.4

申请日：2003-02-05

Applicant: STMicroelectronics S.r.l.

Inventor： Filippini, Gianluca ,  Piccinelli, Emiliano Mario ,  Pau, Danilo Pietro

IPC: H04N7/26 ,  H04N7/50

CPC classification number: H04N19/90 ,  H04N19/124 ,  H04N19/126 ,  H04N19/40

Abstract: Digital signals are converted between a first (IS) and second (OS) format by a conversion process including the step of generating coefficients (X n representing such digital signals. Such coefficients may be e.g. Discrete Cosine Transform (DCT) coefficient generated during encoding/transcoding of MPEG signal. The coefficients are subject to quantization (q) by generating a dither signal (W n ) that is added to the coefficients (X n ) before quantization (q) to generate a quantized signal. Preferably, each coefficient (X n ) is first subject to a first quantization step (q1) in the absence of any dither signal (W n ) added to generate an undithered quantized coefficient. If the undithered quantized signal is equal to zero the undithered quantized coefficient is taken as the output quantized signal. If the undithered quantized coefficient is different from zero, the dither signal (W n ) is added and the dithered coefficient thus obtained is subject to a quantization step (q2) to generate the output quantized signal.

Abstract translation: 通过包括产生系数（Xn表示这种数字信号）的步骤的转换处理，在第一（IS）和第二（OS）格式之间转换数字信号，这样的系数可以是编码/转码期间产生的离散余弦变换（DCT）系数 通过生成与量化前的系数（Xn）相加的抖动信号（Wn）来生成量化信号，对系数进行量化（q），优选地，每个系数（Xn）是第一 在不加任何抖动信号（Wn）的情况下进行第一量化步骤（q1）以生成未抖动的量化系数，如果未调制的量化信号为零，则将未调制量化系数作为输出量化信号，如果 未校准的量化系数不同于零，将抖动信号（Wn）相加，并且由此获得的抖动系数经受量化步长（q2）以产生outpu t量化信号。