[Visual functions of DVD-Video] ![]()
Thanks to the adoption of MPEG2 digital image compression technology, it is possible to achieve excellent picture quality comparable to that of a studio master tape. Compared to MPEG1 which is used for video CDs, etc., MPEG2's image size is approximately 4 times greater and the number of frames per second, 60, is double. With video CD, the data transfer rate which determines the picture quality is fixed at 1.15 Mbit/second, but with DVD it can be set at maximum of 9.80 Mbit/second. Moreover, adoption of variable bit rate makes it possible for the transfer rate to be changed in accordance with the degree of compression. Therefore, picture quality can always be maintained at the optimum level, while at the same time realizing efficient long-playback-time storage on a single disc. Compared with video decks or laser disc players aimed at the mass market, DVD achieves an image with less noise, and that's true even for dark scenes. And because the resolution is so high, outlines are clear, and an image with depth and presence is achieved. With analog equipment the image quality you get basically depends on how much you spend. In contrast, with digital technology excellent picture quality is attainable even with low-cost equipment.
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