DVD refers to "digital versatile disc" or "digital video disc". It is an optical storage disc mainly used for video, audio and computer date storage. With the same size as CD, most DVDs can store more than six times data and run much faster than CDs do. As well, DVD has high quality digital video, audio, picture and other sort information. Standard DVD use red light laser in the wavelength of 650 nm.
DVD physical formats can be described as the way that data is stored on it:
DVD-ROM, means Read Only Memory, the data stored on it can only be read but not written. It is the basic format that data be held.
DVD-R and DVD+R, only can record data one time, the other functions are as DVD-ROM.
DVD-RW, DVD+RW and DVD-RAM, this variation can record, erase and written data many times.
DVD application formats include DVD-Video, DVD-Video Recording (DVD-VR), DVD+RW Video Recording (DVD+VR), DVD-Audio Recording (DVD-AR), DVD-Audio (DVD-A), and Super Audio CD (SACD). DVD-Video and DVD-Audio discs respectively refer to properly formatted and structured video and audio content. Other types of DVDs, including those with video content, may be referred to as DVD-Data discs. There are also special application formats designed for game consoles such as Sony PlayStation 2 and Microsoft Xbox.
DVD achieves computers, business and home entertainment with just a single digital format. Many CD-ROM applications, such as video tape, laser disc and many video game cartridge formats. DVD has widely supported from all major electronics companies, computer hardware companies, and movie and music studios. This unprecedented support makes DVD become the most successful consumer electronic product in history in only less than three years introduction. The years after DVD launch in the market, in 2007, there have been more than one billion DVD devices all over the world, like DVD PCs, DVD players, and DVD game consoles.