The greater amount of information stored on a DVD is chiefly due to the smaller pit size and tighter track spacing,but another factor comes into play,namely compression.

• 一张DVD能储存较大数量的信息，主要是因为光盘较小的凹坑和紧密的轨迹相间隔，但是另外一个因素也发挥了作用，即压缩。