One Byte = 8 bits = 28, or 256 options or quanta levels. CDs can store 670 MB of information and DVDs (single sided) store 4.7GB. DVDs store 4700MB/670MB = seven times more capacity. For example, 50 CDs of music can be stored on seven DVDs. Compression tools can compress disk space from about three to 200 times, depending on the stored information (i.e. text, music, video, etc). Music compresses from 1.2x to 3:1 times (MP3 format for 10:1 times), and text compresses only about three times. But, video can compress enormously, depending upon if is (1) stills, like a picture gallery or a power point presentation, or (2) movies which compress the best (roughly 100 times). The amount of compression of video depends upon the acceptability level (quality control) of lossy compression techniques.
Read more at http://www.datadisc.comFriday, March 7, 2008
Friday, February 1, 2008
Tech Tip: Blu-Ray: The Successor
In the mid 1990s, commercial high definition TV (HDTV) sets began entering a larger market. Since there was no cheap way to record or play back more demanding HD content (4x+), and a non-HD movie already takes up the storage of a single DVD, a new media format was needed. Blue lasers with shorter wavelengths for HD DVDs yield optical storage with higher density than red lasers for DVDs (0.62x for wavelength ratio). As a result, two new competing media were created: HD-DVDs (spearheaded by Toshiba) and Blu-Ray DVDs (led by Sony). However, within the past two years, Warner Bros, Best Buy, Wal-Mart and others stalwarts announced they would no longer support HD-DVD format, but join the Blu-Ray camp. In February of 2008, after losing US$ 1 billion, Toshiba announced its decision to discontinue development and marketing of the HD DVDs. Thus, the backers and followers of Blu-Ray technology won the HD "format war".
read more at http://www.datadisc.com
