Digital Video Recorders

Nov 3
07:45

2011

paul polkinghorne

paul polkinghorne

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A digital video recorder (DVR) is a consumer electronics device or application software that records video in a digital format to a disk drive, USB flash drive, SD memory card or other local or networked mass storage device.

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The term includes set top boxes (STB) with direct to disk recording facility,Digital Video Recorders Articles portable media players (PMP) with recording, camcorders that record onto Secure Digital memory cards and software for personal computers which enables video capture and playback to and from a hard disk. A television set with built in digital video recording facilities was introduced by LG in 2007, followed by other manufacturers.

Consumer digital video recorders Replay TV and TiVo were launched at the 1999 Consumer Electronics Show in Las Vegas, USA. Microsoft also demonstrated a unit with DVR capability, but this did not become available until the end of 1999 for full DVR features in Dish Network's DISHplayer receivers. TiVo shipped their first units on March 31, 1999. Replay TV won the Best of Show award in the video category with Netscape co-founder Marc Andreessen as an early investor and board member, but TiVo was more successful commercially. While early legal action by media companies forced Replay TV to remove many features such as automatic commercial skip and the sharing of recordings over the Internet, newer devices have steadily regained these functions while adding complementary abilities, such as recording onto DVDs and programming and remote control facilities using PDAs, networked PCs, and Web browsers.

Hard disk based digital video recorders make the time shifting feature (traditionally done by a VCR) much more convenient, and also allow for trick modes such as pausing live TV, instant replay of interesting scenes, chasing playback where a recording can be viewed before it has been completed, and skipping of advertising. Most DVRs use the MPEG format for compressing the digitized video signals. Video recording capabilities have become an essential part of the modern set top box, as TV viewers have wanted to take control of their viewing experiences. As consumers have been able to converge increasing amounts of video content on their set tops, delivered by traditional broadcast as well as IP networks, the ability to capture programming and view it whenever they want has become a must have function for many consumers.

In 2003 many Satellite and Cable providers introduced dual tuner digital video recorders. In the UK, BSkyB introduced their first DVR Sky with dual tuner support in 2001. These machines have two independent tuners within the same receiver. The main use for this feature is the capability to record a live program while watching another live program simultaneously or to record two programs at the same time, possibly while watching a previously recorded one. Kogan Technologies introduced a dual tuner DVR in the Australian market allowing free to air television to be recorded on a removable hard drive. Some dual tuner DVRs also have the ability to output to two separate television sets at the same time. The DVR manufactured by UEC (Durban, South Africa) and used by Multichoice and Scientific Atlanta 8300DVB DVR have the ability to view two programs while recording a third using a triple tuner.

Where several digital subchannels are transmitted on a single RF channel, some DVRs can record two channels and view a third, so long as all three subchannels are on two channels (or one). In the United States, DVRs were used by 32 percent of all TV households in 2009, and 38 percent by 2010, with viewership among 18 to 40 year olds 40 percent higher in homes that have them.