HOME

TheInfoList



OR:

A digital video recorder (DVR), also referred to as a personal video recorder (PVR) particularly in
Canadian Canadians () are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of their being ''C ...
and
British English British English is the set of Variety (linguistics), varieties of the English language native to the United Kingdom, especially Great Britain. More narrowly, it can refer specifically to the English language in England, or, more broadly, to ...
, is an
electronic device Electronics is a scientific and engineering discipline that studies and applies the principles of physics to design, create, and operate devices that manipulate electrons and other electrically charged particles. It is a subfield of physics and ...
that records video in a digital format to a disk drive,
USB flash drive A flash drive (also thumb drive, memory stick, and pen drive/pendrive) is a data storage device that includes flash memory with an integrated USB interface. A typical USB drive is removable, rewritable, and smaller than an optical disc, and u ...
, SD
memory card A memory card is an electronic data storage device used for storing digital information, typically using flash memory. These are commonly used in digital portable electronic devices, such as digital cameras as well as in many early games conso ...
,
SSD A solid-state drive (SSD) is a type of solid-state storage device that uses Integrated circuit, integrated circuits to store data persistence (computer science), persistently. It is sometimes called semiconductor storage device, solid-stat ...
or other local or networked
mass storage In computing, mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. In general, the term ''mass'' in ''mass storage'' is used to mean ''large'' in relation to contemporaneous hard disk drive ...
device. The term includes
set-top box A set-top box (STB), also known as a cable converter box, cable box, receiver, or simply box, and historically television decoder or a converter, is an information appliance device that generally contains a Tuner (radio)#Television, TV tuner inpu ...
es (STB) with direct to disk recording,
portable media player A portable media player (PMP) or digital audio player (DAP) is a portable consumer electronics device capable of storing and playing digital media such as audio, images, and video files. Normally they refer to small, Electric battery, batter ...
s and TV gateways with recording capability, and digital
camcorder A camcorder is a self-contained portable electronic device with video and recording as its primary function. It is typically equipped with an articulating screen mounted on the left side, a belt to facilitate holding on the right side, hot-sw ...
s. Personal computers can be connected to video capture devices and used as DVRs; in such cases the
application software Application software is any computer program that is intended for end-user use not operating, administering or programming the computer. An application (app, application program, software application) is any program that can be categorized as ...
used to record video is an integral part of the DVR. Many DVRs are classified as consumer electronic devices. 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.


History


Hard-disk-based digital video recorders

The first working DVR prototype was developed in 1998 at Stanford University Computer Science department. The DVR design was a chapter of Edward Y. Chang's PhD dissertation, supervised by Professors Hector Garcia-Molina and Jennifer Widom. Two design papers were published at the 1998 VLDB conference, and the 1999 ICDE conference. The prototype was developed in 1998 at Pat Hanrahan's CS488 class: Experiments in Digital Television, and the prototype was demoed to industrial partners including Sony, Intel, and Apple. Consumer digital video recorders ReplayTV and
TiVo TiVo ( ) is a digital video recorder (DVR) developed and marketed by Xperi (previously by TiVo Corporation and TiVo Inc.) and introduced in 1999. TiVo provides an on-screen guide of scheduled broadcast programming television programs, whose fea ...
were launched at the 1999
Consumer Electronics Show CES (; formerly an initialism for Consumer Electronics Show) is an annual trade show organized by the Consumer Technology Association (CTA). Held in January at the Las Vegas Convention Center in Winchester, Nevada, United States, the event typi ...
in
Las Vegas, Nevada Las Vegas, colloquially referred to as Vegas, is the most populous city in the U.S. state of Nevada and the county seat of Clark County. The Las Vegas Valley metropolitan area is the largest within the greater Mojave Desert, and second-l ...
. 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. ReplayTV 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. '' Ad Age'' cited
Forrester Research Forrester Research, Inc. is a research and advisory firm. Forrester serves clients in North America, Europe, and Asia Pacific. The firm is headquartered in Cambridge, Massachusetts, Cambridge, MA with global offices in Amsterdam, London, New D ...
as saying that market penetration by the end of 1999 was "less than 100,000". Legal action by media companies forced ReplayTV to remove many features such as automatic commercial skip and the sharing of recordings over the Internet, 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 The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by International Organization for Standardization, ISO and International Electrotechnical Commission, IEC that sets standards for media coding, includ ...
format for compressing the digital video. Video recording capabilities have become an essential part of the modern
set-top box A set-top box (STB), also known as a cable converter box, cable box, receiver, or simply box, and historically television decoder or a converter, is an information appliance device that generally contains a Tuner (radio)#Television, TV tuner inpu ...
, 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 Broadcasting is the data distribution, distribution of sound, audio audiovisual content to dispersed audiences via a electronic medium (communication), mass communications medium, typically one using the electromagnetic spectrum (radio waves), ...
'
cable Cable may refer to: Mechanical * Nautical cable, an assembly of three or more ropes woven against the weave of the ropes, rendering it virtually waterproof * Wire rope, a type of rope that consists of several strands of metal wire laid into a hel ...
,
satellite A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...
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

At the 1999 CES, Dish Network demonstrated the hardware that would later have DVR capability with the assistance of Microsoft software, which also included access to the WebTV service. By the end of 1999 the Dishplayer had full DVR capabilities and within a year, over 200,000 units were sold. 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, although the platform's first DVR, the Pace Twin, dates to 2002. British Sky Broadcasting marketed a popular combined receiver and DVR as Sky+, now replaced by the Sky Q box.
TiVo TiVo ( ) is a digital video recorder (DVR) developed and marketed by Xperi (previously by TiVo Corporation and TiVo Inc.) and introduced in 1999. TiVo provides an on-screen guide of scheduled broadcast programming television programs, whose fea ...
launched a UK model in 2000, and is no longer supported, except for third party services, and the continuation of TiVo through
Virgin Media Virgin Media Limited is a British telecommunications company which provides telephone, television and internet services in the United Kingdom. Its headquarters are at Green Park in Reading, England. It is owned by Virgin Media O2, a 50:50 ...
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
Technicolor SA Vantiva SA (formerly Technicolor SA, Thomson SARL, Thomson SA, and Thomson Multimedia) is a French multinational corporation that provides technology products and services for the communication, media and entertainment industries. Headquarter ...
, Topfield, Fusion, Commscope, Humax, VBox Communications, AC Ryan Playon and Advanced Digital Broadcast (ADB). Many satellite, cable and
IPTV Internet Protocol television (IPTV), also called TV over broadband, is the service delivery of television over Internet Protocol (IP) networks. Usually sold and run by a Telephone company, telecom provider, it consists of broadcast live telev ...
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. 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. 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 Free-to-air (FTA) services are television (TV) and radio services broadcast in unencrypted form, allowing any person with the appropriate receiving equipment to receive the signal and view or listen to the content without requiring a subscri ...
and
Pay TV Pay television, also known as subscription television, premium television or, when referring to an individual service, a premium channel, refers to subscription-based television services, usually provided by multichannel television providers, b ...
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

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. 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 Durban ( ; , from meaning "bay, lagoon") is the third-most populous city in South Africa, after Johannesburg and Cape Town, and the largest city in the Provinces of South Africa, province of KwaZulu-Natal. Situated on the east coast of South ...
, South Africa) and used by
Multichoice MultiChoice is a South Africa, South African company that operates DStv, a major satellite television service in Sub-Saharan Africa. The company also operates GOtv Africa, GOtv, a minor satellite TV service operating in 9 countries, and Showmax, ...
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). 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.Battaglio, Stephen. "Why the New Shows Aren't Working" ''
TV Guide TV Guide is an American digital media In mass communication, digital media is any media (communication), communication media that operates in conjunction with various encoded machine-readable data formats. Digital content can be created, vi ...
''; October 18, 2010; Pages 6–7


Types


Integrated television sets

DVRs are integrated into some
television set A television set or television receiver (more commonly called TV, TV set, television, telly, or tele) is an electronic device for viewing and hearing television broadcasts, or as a computer monitor. It combines a tuner, display, and loudspeake ...
s (TVs). These systems simplify wiring and operation because they employ a single power cable, have no interconnected ports (e.g.,
HDMI High-Definition Multimedia Interface (HDMI) is a proprietary digital interface used to transmit high-quality video and audio signals between devices. It is commonly used to connect devices such as televisions, computer monitors, projectors, gam ...
), and share a common
remote control A remote control, also known colloquially as a remote or clicker, is an consumer electronics, electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operat ...
.


VESA compatibility

VESA VESA (), formally known as Video Electronics Standards Association, is an American standards organization, technical standards organization for computer display standards. The organization was incorporated in California in July 1989To retrieve ...
-compatible DVRs are designed to attach to the VESA mounting holes (100×100 mm) on the back of an LCD television set (TV), allowing users to combine the TV and DVR into an integrated unit.


Set-top boxes (STB)

''Over-the-air'' DVRs are standalone receivers that record broadcast television programs. Several companies have launched over-the-air DVR products for the consumer market over the past few years. Some pay-TV operators provide receivers that allow subscribers to attach their own
network-attached storage Network-attached storage (NAS) is a file-level computer data storage server connected to a computer network providing data access to a Heterogeneous computing, heterogeneous group of clients. In this context, the term "NAS" can refer to both th ...
(NAS) hard drives or solid-state or flash memory to record video and other media files (e.g., audio and photos).


PC-based

Software and hardware are available which can turn personal computers running
Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...
,
Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...
, and
Mac OS X macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...
into DVRs, and is a popular option for home-theater PC (HTPC) enthusiasts.


Linux

There are many free and
open source software Open-source software (OSS) is Software, computer software that is released under a Open-source license, license in which the copyright holder grants users the rights to use, study, change, and Software distribution, distribute the software an ...
DVR applications available for
Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...
. For example, TV gateway interfaces to DVB tuners and provides network tuner and TV server functions, which allows live viewing and recording over IP networks. Other examples include MythTV, Video Disk Recorder (VDR), LinuxMCE,
TiVo TiVo ( ) is a digital video recorder (DVR) developed and marketed by Xperi (previously by TiVo Corporation and TiVo Inc.) and introduced in 1999. TiVo provides an on-screen guide of scheduled broadcast programming television programs, whose fea ...
, VBox Home TV Gateway, and
Kodi Kodi may refer to: Arts, entertainment, and media * KODI, a radio station in Cody, Wyoming, USA * Kodi (film), ''Kodi'' (film), India, 2016 * Kodi, a dog in the 2004 film ''Balto III: Wings of Change'' Other uses * Kodi (software), an open sour ...
(formerly XBMC).


macOS

Geniatech makes a series of digital video recording devices called EyeTV. The software supplied with each device is also called EyeTV, and is available separately for use on compatible third-party tuners from manufacturers such as Pinnacle, TerraTec, and Hauppauge. SageTV provided DVR software for the Mac but no longer sells it. Previously sold devices support the Hauppauge HVR-950, myTV.PVR and HDHomeRun hardware with its DVR software. SageTV software also included the ability to watch YouTube and other online video with a remote control. MythTV (see above) also runs under
Mac OS X macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...
, but most recording devices are currently only supported under Linux. Precompiled binaries are available for the MythTV front-end, allowing a Mac to watch video from (and control) a MythTV server running under Linux. Apple provides applications in the FireWire software developer kit which allow any Mac with a FireWire port to record the MPEG2 transport stream from a FireWire-equipped cable box (for example: Motorola DCT62xx, including HD streams). Applications can also change channels on the cable box via the firewire interface. Only broadcast channels can be recorded as the rest of the channels are encrypted. ''FireRecord (formerly iRecord)'' is a free scheduled-recording program derived from this SDK.


Windows

There are several free digital video recording applications available for
Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...
including GB-PVR, MediaPortal, and Orb (web-based remote interface). There are also several commercial applications available including CyberLink, SageTV (which is no longer available after Google acquired it in June 2011), Beyond TV (which is considered discontinued despite an official announcement from SnapStream since the last update was October 2010 and they are concentrating on their enterprise search products), DVBViewer, Showshifter, InterVideo WinDVR, the R5000-HD and Meedio (now a dead product – Yahoo! bought most of the company's technology and discontinued the Meedio line, and rebranded the software Yahoo! Go – TV, which is now a free product but only works in the U.S.). Most TV tuner cards come bundled with software which allows the PC to record television to hard disk. See TV tuner card. For example, Leadtek's WinFast DTV1000 digital TV card comes bundled with the WinFast PVR2 software, which can also record analog video from the card's composite video input socket. Windows Media Center is a DVR software by Microsoft which was bundled with the Media Center edition of Windows XP, the Home Premium / Ultimate editions of
Windows Vista Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, released five years earlier, which was then the longest time span between successive releases of Microsoft W ...
, as well as most editions of
Windows 7 Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on July 22, 2009, and became generally available on October 22, ...
. When Windows 8 was released in 2012, Windows Media Center was not included with Windows 8 OEM or Retail installations, and was only available as a $15 add-on pack (including DVD Playback codecs) to Windows 8 Pro users. The Windows Game Bar specifies all recordings made by it as being titled "Microsoft Game DVR" followed by the game or application's title.


Embeddable

An ''embeddable'' DVR is a standalone device that is designed to be easily integrated into more complex systems. It is typically supplied as a compact, bare circuit board that facilitates mounting it as a subsystem component within larger equipment. The control keypad is usually connected with a detachable cable, to allow it to be located on the system's exterior while the DVR circuitry resides inside the equipment.


Source video

Television Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...
and
video Video is an Electronics, electronic medium for the recording, copying, playback, broadcasting, and display of moving picture, moving image, visual Media (communication), media. Video was first developed for mechanical television systems, whi ...
are terms that are sometimes used interchangeably, but differ in their technical meaning. Video is the visual portion of television, whereas television is the combination of video and audio modulated onto a
carrier frequency In telecommunications, a carrier wave, carrier signal, or just carrier, is a periodic waveform (usually sinusoidal) that conveys information through a process called ''modulation''. One or more of the wave's properties, such as amplitude or fre ...
(i.e., a television channel) for delivery. Most DVRs can record both video and audio.


Analog sources

The first digital video recorders were designed to record
analog television Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, instantaneous phase and frequency, ...
in
NTSC NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170. In 1953, a second ...
, PAL or
SECAM SECAM, also written SÉCAM (, ''Séquentiel de couleur à mémoire'', French for ''sequential colour memory''), is an analog color television system that was used in France, Russia and some other countries or territories of Europe and Africa. ...
formats. To record an analog signal a few steps are required. In the case of a television signal, a television tuner must first demodulate the radio frequency signal to produce baseband video. The video is then converted to digital form by a frame grabber, which converts each video image into a collection of numeric values that represent the
pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, p ...
s within the image. At the same time, the audio is also converted to digital form by an analog-to-digital converter running at a constant sampling rate. In many devices, the resulting digital video and audio are compressed before recording to reduce the amount of data that will be recorded, although some DVRs record uncompressed data. When compression is used, video is typically compressed using formats such as H.264 or MPEG-2, and audio is compressed using AAC or MP3.


Analog broadcast copy protection

Many consumer DVRs implement a copy-protection system called ''Copy Generation Management System—Analog'' ( CGMS-A), which specifies one of four possible copy permissions by means of two bits encoded in the vertical blanking interval: * Copying is freely allowed * Copying is prohibited * Only one copy of this material may be made * This is a copy of material for which only one copy was allowed to be made, so no further copies are allowed. CGMS-A information may be present in analog broadcast TV signals, and is preserved when the signal is recorded and played back by analog VCRs. VCRs do not understand the meanings of the bits but preserve them in case there is a subsequent attempt to copy the tape to a DVR. DVRs such as TiVo also detect and act upon analog protection systems such as Macrovision and DCS Copy Protection which were originally designed to block copying on analog VCRs.


Digital sources

Recording digital signals is generally a straightforward capture of the binary
MPEG The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by International Organization for Standardization, ISO and International Electrotechnical Commission, IEC that sets standards for media coding, includ ...
data being received. No expensive hardware is required to quantize and compress the signal (as the
television broadcaster A television broadcaster or television network is a telecommunications network for the distribution of television show, television content, where a central operation provides programming to many television stations, pay television providers or ...
has already done this in the studio). DVD-based PVRs available on the market as of 2006 are not capable of capturing the full range of the visual signal available with
high-definition television High-definition television (HDTV) describes a television or video system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since at least 1933; in more recent times, it ref ...
(HDTV). This is largely because HDTV standards were finalized at a later time than the standards for DVDs. However, DVD-based PVRs can still be used (albeit at reduced visual quality) with HDTV since currently available HDTV sets also have standard A/V connections.


ATSC broadcast

ATSC television broadcasting is primarily used in North America. The ATSC data stream can be directly recorded by a digital video recorder, though many DVRs record only a subset of this information (that can later be transferred to DVD). An ATSC DVR will also act as a
set-top box A set-top box (STB), also known as a cable converter box, cable box, receiver, or simply box, and historically television decoder or a converter, is an information appliance device that generally contains a Tuner (radio)#Television, TV tuner inpu ...
, allowing older televisions or monitors to receive digital television.


=Copy protection

= The U.S. FCC attempted to limit the abilities of DVRs with its "
broadcast flag A broadcast flag is a bit field sent in the data stream of a digital television program that indicates whether or not the data stream can be recorded, or if there are any restrictions on recorded content. Possible restrictions include the inabili ...
" regulation. Digital video recorders that had not won prior approval from the FCC for implementing "effective"
digital rights management Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures, such as access control technologies, can restrict the use of proprietary hardware and copyrighted works. DRM ...
would have been banned from
interstate commerce The Commerce Clause describes an enumerated power listed in the United States Constitution ( Article I, Section 8, Clause 3). The clause states that the United States Congress shall have power "to regulate Commerce with foreign Nations, and amon ...
from July 2005, but the regulation was struck down on May 6, 2005.


DVB

DVB
digital television Digital television (DTV) is the transmission of television signals using Digital signal, digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an ...
contains audio/visual signals that are broadcast over the air in a
digital Digital usually refers to something using discrete digits, often binary digits. Businesses *Digital bank, a form of financial institution *Digital Equipment Corporation (DEC) or Digital, a computer company *Digital Research (DR or DRI), a software ...
rather than analog format. The DVB data stream can be directly recorded by the DVR. Devices that can use external storage devices (such as hard disks, SSDs, or other flash storage) to store and recover data without the aid of another device are sometimes called telememory devices.


Digital cable and satellite television

Recording
satellite television Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location.ITU Radio Regulations, Section IV. Radio Stations and Systems ...
or digital cable signals on a digital video recorder can be more complex than recording analog signals or broadcast digital signals. There are several different transmission schemes, and the video streams may be encrypted to restrict access to subscribers only. A satellite or cable
set-top box A set-top box (STB), also known as a cable converter box, cable box, receiver, or simply box, and historically television decoder or a converter, is an information appliance device that generally contains a Tuner (radio)#Television, TV tuner inpu ...
both decrypts the signal if encrypted, and decodes the MPEG stream into an analog signal for viewing on the television. In order to record cable or satellite digital signals the signal must be captured after it has been decrypted but before it is decoded; this is how DVRs built into set-top boxes work. Cable and satellite providers often offer their own digital video recorders along with a service plan. These DVRs have access to the encrypted video stream, and generally enforce the provider's restrictions on copying of material even after recording.


DVD

Many DVD-based DVRs have the capability to copy content from a source DVD ( ripping). In the United States, this is prohibited under the
Digital Millennium Copyright Act The Digital Millennium Copyright Act (DMCA) is a 1998 United States copyright law that implements two 1996 treaties of the World Intellectual Property Organization (WIPO). It criminalizes production and dissemination of technology, devices, or ...
if the disc is encrypted. Most such DVRs will therefore not allow recording of video streams from encrypted movie discs.


Digital camcorders

A digital
camcorder A camcorder is a self-contained portable electronic device with video and recording as its primary function. It is typically equipped with an articulating screen mounted on the left side, a belt to facilitate holding on the right side, hot-sw ...
combines a camera and a digital video recorder. Some DVD-based DVRs incorporate connectors that can be used to capture digital video from a camcorder. Some editing of the resulting DVD is usually possible, such as adding chapter points. Some digital video recorders can now record to solid state flash memory cards (called ''flash camcorders''). They generally use Secure Digital cards, can include wireless connections (
Bluetooth Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is li ...
and
Wi-Fi Wi-Fi () is a family of wireless network protocols based on the IEEE 802.11 family of standards, which are commonly used for Wireless LAN, local area networking of devices and Internet access, allowing nearby digital devices to exchange data by ...
), and can play SWF files. There are some digital video recorders that combine video and graphics in real time to the flash card, called DTE or "direct to edit". These are used to speed-up the editing workflow in video and television production, since linear videotapes do not then need to be transferred to the edit workstation (see
Non-linear editing system Non-linear editing (NLE) is a form of offline editing for audio, video, and image editing. In offline editing, the original content is not modified in the course of editing. In non-linear editing, edits are specified and modified by speciali ...
).


File formats, resolutions and file systems

DVRs can usually record and play H.264, MPEG-4 Part 2, MPEG-2 .mpg, MPEG-2 . TS, VOB and ISO images video, with MP3 and AC3 audio tracks. They can also display images (
JPEG JPEG ( , short for Joint Photographic Experts Group and sometimes retroactively referred to as JPEG 1) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degr ...
and PNG) and play music files ( MP3 and Ogg). Some devices can be updated to play and record in new formats. DVRs usually record in proprietary file systems for
copy protection Copy protection, also known as content protection, copy prevention and copy restriction, is any measure to enforce copyright by preventing the reproduction of software, films, music, and other media. Copy protection is most commonly found on vid ...
, although some can use
FAT In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers specif ...
file systems. Recordings from
standard-definition television Standard-definition television (SDTV; also standard definition or SD) is a television system that uses a resolution that is not considered to be either high or enhanced definition. ''Standard'' refers to offering a similar resolution to the ...
usually have 480p/i/576p/i while
HDTV High-definition television (HDTV) describes a television or video system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since at least 1933; in more recent times, it ref ...
is usually in 720p/1080i.


Applications


Security

Digital video recorders configured for
physical security Physical security describes security measures that are designed to deny unauthorized access to facilities, equipment, and resources and to protect personnel and property from damage or harm (such as espionage, theft, or terrorist attacks). Physi ...
applications record video signals from
closed-circuit television Closed-circuit television (CCTV), also known as video surveillance, is the use of closed-circuit television cameras to transmit a signal to a specific place on a limited set of monitors. It differs from broadcast television in that the signa ...
cameras for detection and documentation purposes. Many are designed to record audio as well. DVRs have evolved into devices that are feature rich and provide services that exceed the simple recording of video images that was previously done through VCRs. A DVR CCTV system provides a multitude of advanced functions over VCR technology including video searches by event, time, date and camera. There is also much more control over quality and frame rate allowing disk space usage to be optimized and the DVR can also be set to overwrite the oldest security footage should the disk become full. In some DVR security systems remote access to security footage using a PC can also be achieved by connecting the DVR to a LAN network or the Internet. Some of the latest professional digital video recorders include video analytics firmware, to enable functionality such as 'virtual tripwire' or even the detection of abandoned objects on the scene. Security DVRs may be categorized as being either PC-based or embedded. A PC-based DVR's architecture is a classical personal computer with video capture cards designed to capture video images. An embedded type DVR is specifically designed as a digital video recorder with its
operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...
and
application software Application software is any computer program that is intended for end-user use not operating, administering or programming the computer. An application (app, application program, software application) is any program that can be categorized as ...
contained in
firmware In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, h ...
or
read-only memory Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing sof ...
.


Hardware features

Hardware features of security DVRs vary between manufacturers and may include but are not necessarily limited to: * Designed for rack mounting or desktop configurations. * Single or multiple video inputs with connector types consistent with the analogue or digital video provided such as
coaxial cable Coaxial cable, or coax (pronounced ), is a type of electrical cable consisting of an inner Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulat ...
, twisted pair or
optical fiber cable A fiber-optic cable, also known as an optical-fiber cable, is an assembly similar to an electrical cable but containing one or more optical fibers that are used to carry light. The optical fiber elements are typically individually coated with p ...
. The most common number of inputs are 1, 2, 4, 8, 16 and 32. Systems may be configured with a very large number of inputs by networking or bussing individual DVRs together. * Looping video outputs for each input which duplicates the corresponding input video signal and connector type. These output signals are used by other video equipment such as matrix switchers,
multiplexer In electronics, a multiplexer (or mux; spelled sometimes as multiplexor), also known as a data selector, is a device that selects between several Analog signal, analog or Digital signal (electronics), digital input signals and forwards the sel ...
s, and
video monitor A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signa ...
s. * Controlled outputs to external video display monitors. * Front panel switches and indicators that allow the various features of the machine to be controlled. * Network connections consistent with the network type and utilized to control features of the recorder and to send and/or receive video signals. * Connections to external control devices such as keyboards. * A connection to external pan-tilt-zoom drives that position cameras. * Internal CD, DVD, VCR devices typically for archiving video. * Connections to external storage media. * Alarm event inputs from external security detection devices, usually one per video input. * Alarm event outputs from internal detection features such as motion detection or loss of video.


Software features

Software features vary between manufacturers and may include but are not necessarily limited to: * User-selectable image capture rates either on an all input basis or input by input basis. The capture rate feature may be programmed to automatically adjust the capture rate on the occurrence of an external alarm or an internal event * Selectable
image resolution Image resolution is the level of detail of an image. The term applies to digital images, film images, and other types of images. "Higher resolution" means more image detail. Image resolution can be measured in various ways. Resolution quantifies ...
either on an all input basis or input by input basis. The image resolution feature may be programmed to automatically adjust the image resolution on the occurrence of an external alarm or an internal event. * Compression methods determine quality of playback. H.264 hardware compression offers fast transfer rates over the Internet with high quality video. * Motion detection: Provided on an input by input basis, this feature detects motion in the total image or a user definable portion of the image and usually provides sensitivity settings. Detection causes an internal event that may be output to external equipment and/or be used to trigger changes in other internal features. * Lack of motion detection. Provided on an input by input basis, this feature detects the movement of an object into the field of view and remaining still for a user definable time. Detection causes an internal event that may be output to external equipment and/or used to trigger changes in other internal features. * Direction of motion detection. Provided on an input by input basis, this feature detects the direction of motion in the image that has been determined by the user as an unacceptable occurrence. Detection causes an internal event that may be output to external equipment and/or be used to trigger changes in other internal features. * Routing of input video to video monitors based on user inputs or automatically on alarms or events. * Input, time and date stamping. *
Alarm ALARM (Air Launched Anti-Radiation Missile) is a British anti-radiation missile designed primarily to destroy enemy radars for the purpose of Suppression of Enemy Air Defenses (SEAD). It was used by the Royal Air Force, RAF and is still used by ...
and event logging on appropriate video inputs. * Alarm and event search. * One or more sound recording channels. * Archival.


Privacy concerns

Some (very few), but certainly not all, digital video recorders which are designed to send information to a service provider over a
telephone line A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. It is designed to reproduce speech of a quality that is understandable. It is the physical wire or oth ...
or
Internet The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...
(or any other way) can gather and send real-time data on users' viewing habits. This problem was noted back in 2000 and was still considered a problem, specifically with TiVo, in 2015.


Television advertisements

Digital video recorders are also changing the way television programs advertise products. Watching pre-recorded programs allows users to fast-forward through
commercials A television advertisement (also called a commercial, spot, break, advert, or ad) is a span of television programming produced and paid for by an organization. It conveys a message promoting, and aiming to market, a product, service or idea. ...
, and some technology allows users to remove commercials entirely. Half of viewers in the United States, for example, use DVRs to skip commercials entirely. This feature has been controversial for the last decade, with major television networks and movie studios claiming it violates copyright and should be banned. In 1985, an employee of Honeywell's Physical Sciences Center, David Rafner, first described a drive-based DVR designed for home TV recording, time shifting, and commercial skipping. U.S. Patent 4,972,396 focused on a multi-channel design to allow simultaneous independent recording and playback. Broadly anticipating future DVR developments, it describes possible applications such as streaming compression, editing, captioning, multi-channel security monitoring, military sensor platforms, and remotely piloted vehicles. In 1999, the first DVR which had a built-in commercial skipping feature was introduced by ReplayTV at the
Consumer Electronics Show CES (; formerly an initialism for Consumer Electronics Show) is an annual trade show organized by the Consumer Technology Association (CTA). Held in January at the Las Vegas Convention Center in Winchester, Nevada, United States, the event typi ...
in Las Vegas. In 2002, five owners of the ReplayTV DVR sued the main television networks and movie studios, asking the federal judge to uphold consumers' rights to record TV shows and skip commercials, claiming that features such as commercial skipping help parents protect their kids from excessive
consumerism Consumerism is a socio-cultural and economic phenomenon that is typical of industrialized societies. It is characterized by the continuous acquisition of goods and services in ever-increasing quantities. In contemporary consumer society, the ...
. ReplayTV was purchased by SONICblue in 2001 and in March 2003, SONICblue filed for Chapter 11 bankruptcy after fighting a copyright infringement suit over the ReplayTV's ability to skip commercials. In 2007,
DirecTV DirecTV, LLC is an American Multichannel television in the United States, multichannel video programming distributor based in El Segundo, California. Originally launched on June 17, 1994, its primary service is a digital Satellite television, s ...
purchased the remaining assets of ReplayTV. A third-party add-on for Windows Media Center called "DVRMSToolbox" has the ability to skip commercials. There is a command-line program called Comskip that detects commercials in an MPEG-2 file and saves their positions to a text file. This file can then be fed to a program like MEncoder to actually remove the commercials. Many speculate that television advertisements will be eliminated altogether, replaced by advertising in the TV shows themselves. For example, ''Extreme Makeover: Home Edition'' advertises
Sears Sears, Roebuck and Co., commonly known as Sears ( ), is an American chain of department stores and online retailer founded in 1892 by Richard Warren Sears and Alvah Curtis Roebuck and reincorporated in 1906 by Richard Sears and Julius Rosen ...
, Kenmore, Kohler, and
Home Depot The Home Depot, Inc., often referred to as Home Depot, is an American multinational corporation, multinational home improvement retail corporation that sells tools, construction products, appliances, and services, including fuel and transportat ...
by specifically using products from these companies, and some sports events like the Sprint Cup of
NASCAR The National Association for Stock Car Auto Racing, LLC (NASCAR) is an American auto racing sanctioning and operating company that is best known for stock car racing. It is considered to be one of the top ranked motorsports organizations in ...
are named after sponsors. Another type of advertisement shown more and more, mostly for advertising television shows on the same channel, is where the ad overlays the bottom of the television screen, blocking out some of the picture. "Banners", or "logo bugs", as they are called, are referred to by media companies as Secondary Events (2E). This is done in much the same way as severe weather warnings are done. Sometimes, these take up only 5–10% of the screen, but in the extreme, can take up as much as 25% of the viewing area. Some even make noise or move across the screen. One example of this is the 2E ads for '' Three Moons Over Milford'' in the months before its premiere. A video taking up approximately 25% of the bottom-left portion of the screen would show a comet impacting into the moon with an accompanying explosion, during another television program. Because of this widely used new technology, advertisers are now looking at a new way to market their products on television. An excerpt from the magazine ''
Advertising Age ''Ad Age'' (known as ''Advertising Age'' until 2017) is a global media brand that publishes news, analysis, and data on marketing and media. Its namesake magazine was started as a broadsheet newspaper in Chicago in 1930. ''Ad Age'' appears in ...
'' reads: "As advertisers lose the ability to invade the home, and consumer's minds, they will be forced to wait for an invitation. This means that they have to learn what kinds of advertising content customers will actually be willing to seek out and receive." With ad skipping and the time-sensitive nature of certain ads, advertisers are wary of buying commercial time on shows that are heavily digitally video-recorded. However, technology today makes it possible for networks to insert ads dynamically on videos being played in DVRs. Advertisers could inject time-relevant ads to recorded programs when the program is viewed. This way the ads could be not just topical but also personalized to viewers interests.
DirecTV DirecTV, LLC is an American Multichannel television in the United States, multichannel video programming distributor based in El Segundo, California. Originally launched on June 17, 1994, its primary service is a digital Satellite television, s ...
in March 2011 signed an arrangement with NDS Group to enable the delivery of such addressable advertisement. It is believed that viewers prefer to forward ads, than to switch the channel. By switching channels, viewers will have the probability of skipping the beginning of their program. Users might switch to a channel that is also showing ads. Having the ability to pause, rewind, and forward live TV gives users a chance to change the channel fewer times. Forwarding ads can have a later effect on the viewer. Ads that get the viewers' attention will influence the viewers' to rewind and watch what was missed. In January 2012, Dish Network announced Hopper service, costing $10 extra per month, which recorded prime-time programming from the four major broadcast networks. With the Auto Hop feature, viewers can watch the programs they choose without commercials, without making the effort to fast-forward. On May 24, 2012, Dish and the networks filed suit in federal court.


Patent and copyright litigation

On July 14, 2005, Forgent Networks filed suit against various companies alleging infringement on , entitled "Computer controlled video system allowing playback during recording". The listed companies included EchoStar, DirecTV, Charter Communications, Cox Communications, Comcast, Time Warner, and Cable One. Scientific-Atlanta and
Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois. It was founded by brothers Paul and Joseph Galvin in 1928 and had been named Motorola since 1947. Many of Motorola's products had been ...
, the manufacturers of the equipment sold by the above-mentioned companies, filed a counter-suit against Forgent Networks claiming that their products do not violate the patent, and that the patent is invalid. The two cases were combined into case 6:06-cv-208, filed in the United States District Court for the Eastern District of Texas, Tyler Division. According to court documents, on June 20, 2006, Motorola requested that the United States Patent and Trademarks Office reexamine the patent, which was first filed in 1991, but has been amended several times. On March 23, 2007, Cablevision Systems Corp lost a legal battle against several Hollywood studios and television networks to introduce a network-based digital video recorder service to its subscribers. However, on August 4, 2008, Cablevision won its appeal. John M. Walker Jr., a Second Circuit judge, declared that the technology "would not directly infringe" on the media companies' rights. An appeal to the Supreme Court was rejected. In court, the media companies argued that network digital video recorders were tantamount to video-on-demand, and that they should receive license fees for the recording. Cablevision and the appeals court disagreed. The company noted that each user would record programs on his or her own individual server space, making it a DVR that has a "very long cord". In 2004, TiVo sued EchoStar Corp, a manufacturer of DVR units, for patent infringement. The parties reached a settlement in 2011 wherein EchoStar pays a one-time fee (in three structured payments) that grants Echostar full rights for life to the disputed TiVo patents upon first payment(as opposed to indefinite and escalating license fees to be constantly renegotiated), and Echostar granted TiVo full rights for life to certain Echostar patents and dropped their counter-suit against TiVo. In January 2012, AT&T settled a similar suit brought by TiVo claiming patent infringement (just as with Echostar) in exchange for cash payments to TiVo totaling $215 million through June 2018 plus "incremental recurring per subscriber monthly license fees" to TiVo through July 2018, but grants no full lifetime rights as per the Echostar settlement. In May 2012, Fox Broadcasting sued Dish Network, arguing that Dish's set-top box with DVR function, which allowed the users to automatically record prime-time programs and skip commercials, was copyright infringement and breach of contract. In July 2013, the 9th circuit rejected Fox's claims.


See also

*
Set-top box A set-top box (STB), also known as a cable converter box, cable box, receiver, or simply box, and historically television decoder or a converter, is an information appliance device that generally contains a Tuner (radio)#Television, TV tuner inpu ...
* Home theater PC (Media PC) * Digital media player *
Smart TV A smart TV, also known as a connected TV (CTV or, rarely, CoTV), is a traditional television set with integrated Internet and interactive Web 2.0 features that allow users to stream music and videos, browse the internet, and view photos. Smart T ...
* Comparison of PVR software packages * 10-foot user interface * CRID *
Direct-to-disk recording A hard disk recorder (HDR) is a system that uses a high-capacity hard disk to record digital audio or digital video. Hard disk recording systems represent an alternative to reel-to-reel audio tape recording and video tape recorders, and provide n ...
* DTE (Direct To Edit) * DTVPal * Freeview+ * Freesat+ * Hopper (DVR) * * Media server (Consumer) * Time shifting * Space shifting (place shifting) * Remote storage digital video recorder * MythTV * Network video recorder * SubRip * Sky+ * Tablo (DVR) *
TiVo TiVo ( ) is a digital video recorder (DVR) developed and marketed by Xperi (previously by TiVo Corporation and TiVo Inc.) and introduced in 1999. TiVo provides an on-screen guide of scheduled broadcast programming television programs, whose fea ...
* TV-Anytime * PVR-resistant advertising *
Remote control A remote control, also known colloquially as a remote or clicker, is an consumer electronics, electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operat ...
* USB hard disk * USB On-The-Go * Vu+ * Video server (Broadcast) * Kodi (software) *
Xbox One The Xbox One is a home video game console developed by Microsoft. Announced in May 2013, it is the successor to Xbox 360 and the third console in the Xbox#Consoles, Xbox series. It was first released in North America, parts of Europe, Austra ...


Notes


References


Free-to-Air Television and other PVR Challenges in Europe
, technical report of the
European broadcasting union The European Broadcasting Union (EBU; , UER) is an alliance of Public broadcasting, public service media organisations in countries within the European Broadcasting Area (EBA) or who are member states of the Council of Europe, members of the ...
{{DEFAULTSORT:Digital Video Recorder Digital media Set-top box Television terminology