DVD技术的发展是很快的,新产品越来越多,让人目不暇接。最近市场上又出现了一种逐行扫描DVD机(PDVD),引起了大家的关注,但是许多人对这种新产品并不十分了解。PDVD到底是怎么回事?它到底有什么优点和缺点?它会成为今后的主流产品吗?要了解这些,还是让我们从最基本的原理开始说起。 隔行扫描与逐行扫描 我们知道,一幅完整的电视画面是由若干条扫描线组成的,例如PAL制为每幅画面625条扫描线。这样的一幅画面称为一“帧”。在隔行扫描方式下,一帧画面需要由两遍扫描完成,第一遍只扫描奇数行,即1、3、5、7、9……行,第二遍只扫描偶数行,即2、4、6、8……行。这样的一遍扫描称为一“场”。两个场的扫描虽然不是同时发生的,但由于显像管的余辉和我们眼睛 DVD technology is developing rapidly, more and more new products, people dizzying. The recent emergence of a progressive-scan DVD player (PDVD) on the market has aroused everyone’s attention, but many people do not quite understand this new product. What is PDVD in the end? What are its advantages and disadvantages in the end? It will become the mainstream products in the future? To understand this, let us start from the most basic principle. Interlaced and Progressive Scanning We know that a complete television picture consists of a number of scan lines, such as PAL, which produces 625 scan lines per picture. Such a picture is called a “frame.” In the interlaced mode, a picture needs to be scanned by two passes, the first pass only scans the odd lines, ie 1, 3, 5, 7, 9 ..., the second passes only the even lines, ie 2, 4 , 6,8 ...... OK. Such a scan is called a “field.” Although the two field scanning is not simultaneous, but because of the persistence of the CRT and our eyes