Digital video recorder - DVR
Digital video recorder - DVR

A digital video recorder (DVR) is an electronic device that records video in a digital format to a disk drive, USB flash drive, SD memory card, SSD or other local or networked mass storage device. The term includes set-top boxes with direct to disk recording, portable media players and TV gateways with recording capability, and digital camcorders.[1] Personal computers are often connected to video capture devices and used as DVRs; in such cases the application software used to record video is an integral part of the DVR. Many DVRs are classified as consumer electronic devices; such devices may alternatively be referred to as personal video recorders (PVRs), particularly in Canada. Similar small devices with built-in (~5 inch diagonal) displays and SSD support may be used for professional film or video production, as these recorders often do not have the limitations that built-in recorders in cameras have, offering wider codec support, the removal of recording time limitations and higher bitrates.

Contents

 

1History

o 1.1Hard-disk-based digital video recorders

1.1.1Digital video recorders tied to a video service

o 1.2Introduction of dual tuners

2Types

o 2.1Integrated television sets

o 2.2VESA compatibility

o 2.3Set-top boxes

o 2.4PC-based

2.4.1Linux

2.4.2Mac OS

2.4.3Windows

o 2.5Embeddable

3Source video

o 3.1Analog sources

3.1.1Analog broadcast copy protection

o 3.2Digital sources

3.2.1ATSC broadcast

3.2.1.1Copy protection

3.2.2DVB

3.2.3Digital cable and satellite television

3.2.4DVD

3.2.5Digital camcorders

4File formats, resolutions and file systems

5Applications

o 5.1Security

5.1.1Hardware features

5.1.2Software features

6Privacy concerns

7Television advertisements

8Patent and copyright litigation

9See also

10Notes

11References

 

12External links

 

Hard-disk-based digital video recorders

Back view of a TiVo Series2 5xx-generation unit

Consumer digital video recorders ReplayTV and TiVo were launched at the 1999 Consumer Electronics Show in Las Vegas, Nevada.[2] 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.[3] ReplayTV won the "Best of Show" award in the video category[4] with Netscape co-founder Marc Andreessen as an early investor and board member,[5] but TiVo was more successful commercially.

Legal action by media companies forced ReplayTV to remove many features such as automatic commercial skip and the sharing of recordings over the Internet,[6] but 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.

In contrast to VCRs, hard-disk based digital video recorders make "time shifting" more convenient and also allow for functions such as pausing live TV, instant replay, chasing playback (viewing a recording before it has been completed) and skipping over advertising during playback.

Many DVRs use the MPEG format for compressing the digital video.[7] 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' cable, satellite and terrestrial 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.

Digital video recorders tied to a video service[edit]

At the 1999 CES, Dish Network demonstrated the hardware that would later have DVR capability with the assistance of Microsoft software.[8] which also included WebTV Networks internet TV.[8] By the end of 1999 the Dishplayer had full DVR capabilities and within a year, over 200,000 units were sold.[9][10]

In the UK, digital video recorders are often referred to as "plus boxes" (such as BSKYB's Sky+ and Virgin Media's V+ which integrates an HD capability, and the subscription free Freesat+ and Freeview+). Freeview+ have been around in the UK since the late 2000s. British Sky Broadcasting markets a popular combined receiver and DVR as Sky+. TiVo launched a UK model in 2000, and is no longer supported, except for third party services, and the continuation of TiVo through Virgin Media in 2010. South African based Africa Satellite TV beamer Multichoice recently launched their DVR which is available on their DStv platform. In addition to ReplayTV and TiVo, there are a number of other suppliers of digital terrestrial (DTT) DVRs, including Thomson, Topfield, Fusion, Pace Micro Technology, Humax, VBox Communications, AC Ryan Playon and Advanced Digital Broadcast (ADB).

Many satellite, cable and IPTV companies are incorporating digital video recording functions into their set-top box, such as with DirecTiVo, DISHPlayer/DishDVR, Scientific Atlanta Explorer 8xxx from Time Warner, Total Home DVR from AT&T U-verse, Motorola DCT6412 from Comcast and others, Moxi Media Center by Digeo (available through Charter, Adelphia, Sunflower, Bend Broadband, and soon Comcast and other cable companies), or Sky+. Astro introduced their DVR system, called Astro MAX, which was the first PVR in Malaysia but was phased out two years after its introduction.

In the case of digital television, there is no encoding necessary in the DVR since the signal is already a digitally encoded MPEG stream. The digital video recorder simply stores the digital stream directly to disk. Having the broadcaster involved with, and sometimes subsidizing, the design of the DVR can lead to features such as the ability to use interactive TV on recorded shows, pre-loading of programs, or directly recording encrypted digital streams. It can, however, also force the manufacturer to implement non-skippable advertisements and automatically expiring recordings.

In the United States, the FCC has ruled that starting on July 1, 2007, consumers will be able to purchase a set-top box from a third-party company, rather than being forced to purchase or rent the set-top box from their cable company.[11] This ruling only applies to "navigation devices," otherwise known as a cable television set-top box, and not to the security functions that control the user's access to the content of the cable operator.[12] The overall net effect on digital video recorders and related technology is unlikely to be substantial as standalone DVRs are currently readily available on the open market.

In Europe Free-To-Air[13] and Pay TV[14] TV gateways with multiple tuners have whole house recording capabilities allowing recording of TV programs to Network Attached Storage or attached USB storage, recorded programs are then shared across the home network to tablet, smartphone, PC, Mac, Smart TV.

Introduction of dual tuners[edit]

In 2003 many Satellite and Cable providers introduced dual-tuner digital video recorders. In the UK, BSkyB introduced their first PVR Sky+ with dual tuner support in 2001.[15] 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.com introduced a dual-tuner PVR 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 PVR manufactured by UEC (Durban, South Africa) and used by Multichoice and Scientific Atlanta 8300DVB PVR 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 PVRs can record two channels and view a third, so long as all three subchannels are on two channels (or one).[16]

 

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.[17]

 

Side view of an LCD monitor with built-in DVR

DVRs are integrated into some television sets (TVs). These systems simplify wiring and operation because they employ a single power cable, have no interconnected ports (e.g., HDMI), and share a common remote control.

 

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