What+is+a+DVD+and+how+does+a+DVD+Player+work?


 * WHAT IS A DVD AND HOW DOES A DVD PLAYER WORK **

A DVD is a digital video disc, which has more space than a CD, which has only 4.7 GB, while a DVD has about 12.5 GB of storage. A DVD player works by using these steps. First, a drive motor will spin the disc around. Second, a laser and lens system focuses on the bumps and reads them. Lastly, a tracking mechanism moves the laser assembly so that the laser beam can follow the track.Then the tracking system has to be able to move the laser at micron resolutions. Then the movie starts up. A DVD plays when you put the DVD in, and you have to put it in properly.

Blu-ray discs are a different kind of disc compared to a DVD. A Blu-ray player only plays certain movies(Blu-ray ones) while a DVD can play the movies that are out. A Blu-ray disc can hold up to 50 GB, while a regular DVD can only hold 4.7 GB. A Blu-ray disc can be more money than a regular DVD, but a Blu-ray disc is has better quality and is clearer than a DVD.
 * Blu-ray Discs **



A DVD is very similar to a CD but it has a much larger capacity A single layer DVD holds about 7 times more data than a CD, which means it has enough room to store a full-length, MPEG 2-encoded movie, as well as slot of other information A DVD movie usually includes the following-
 * Fun Facts **
 * up to 133 min of high resolution video
 * The video compression ratio is typically 40:1, using MPEG-2 compression
 * a soundtrack presented in to eight languages, using 5.1 Dolby digital surround sound
 *  Subtitles up to 32 languages




 * Glossary **
 * DVD **- digital video disc
 * GB **<span style="font-family: Arial,sans-serif; font-size: 12pt;">- gigabyte, a type of space that is bigger than a megabyte.
 * <span style="font-family: Arial,sans-serif; font-size: 12pt;">Blu-ray **<span style="font-family: Arial,sans-serif; font-size: 12pt;">- <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">an <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|optical disc] [|storage medium] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;"> designed to supersede the <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|DVD] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;"> format.
 * <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">Subtitles **<span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">- the little words you sometimes see at the bottom of a movie or TV screen
 * <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">Video compression ratio **<span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">- The size of the video signal that's not yet compressed, compared to that same signal after it's compressed.
 * <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">High resolution **<span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">- **HRHD (high-resolution high-definition)** (also **HR**, **HRHDTV**, or **HR.HDTV**) is an <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|initialism] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;"> referring to an <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|image resolution] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;"> derived from <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|high-definition video] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">, often seen as part of the <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|filename] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;"> of TV shows shared on the Internet
 * <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">MPEG-Moving Picture Experts Group **<span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">- The **Moving Picture Experts Group** (**MPEG**) is a <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|working group] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;"> of experts that was formed by <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|ISO] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;"> and <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|IEC] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;"> to set standards for <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|audio] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;">and <span style="color: #0b0080; font-family: Arial,sans-serif; font-size: 12pt;">[|video compression] <span style="background-color: white; font-family: Arial,sans-serif; font-size: 12pt;"> and transmission

Brain, Marshall. How //Stuff Works.// New York. Hungry Minds.2001.Print. McGrath, Kimberly A. //The Gale Encyclopedia of Science.// Farmington Hills, MI. Gale Group//.// 2001. Print. DVD. Wikipedia. Wikipedia. September 28, 2012. Web. September 19,2012. <span style="background-color: #ebebeb; font-family: Arial,sans-serif; font-size: 12pt;">"**DVD.**" //Encyclopedia Britannica//. //Encyclopedia Britannica Online School Edition//.
 * <span style="font-family: Arial,sans-serif; font-size: 12pt;">Citations **

<span style="font-family: Arial,sans-serif; font-size: 12pt;">Encyclopedia Britannica, Inc., 2012. Web. 27 Sept. 2012.