Released in 1995, DVD is a removable storage device. They quickly overtook VHS to become the most popular format for the distribution of video due to their durability (approximately 100 years) and the superior quality of the image. DVD is slowly being overtaken by Blu-Ray which provides a further improvement in terms of quality. Another threat to the sales of DVDs are the rise of online streaming services such as Netflix which allow a user instant access to video with similar or superior picture quality. At its peak several hundred million DVDs were sold yearly.
DVD uses a MPEG-1 or MPEG-2 compression, however MPEG-2 supports higher resolution, up to 720x576 pixels. The DVD format also supports several types of audio including MP2 and Dolby Digital. A DVD may also include subtitles which are stored as bitmap images meaning that any language can be stored as subtitles. DVDs may also contain chapters which allow the user to easily navigate to a specific point in the video. Although not part of the official DVD Video specification, a number of distributors have added copy protection to limit the ease with which a DVD may be ripped and copied.
WMV files are a type of video file (usually containing audio) from Microsoft. These files can be played on a variety of video players on both Mac and PC machines. Some WMV files may have digital rights management (DRM) protection which prevents users from making unauthorized copies of files purchased in online stores.
Windows Media Video (WMV) is a compressed video file format for several proprietary codecs developed by Microsoft. These files are based on the Microsoft Advanced Systems Format (ASF) container format encoded using the Windows Media Video (WMV) codec.
MPlayer Microsoft Windows Media Player PowerDVD RealPlayer VideoLAN VLC Media Player