Digital video recorder
This article's lead section may be too short to adequately summarize the key points. (November 2023) |
A digital video recorder (DVR) is an
History
Hard-disk-based digital video recorders
The first working DVR prototype
Consumer digital video recorders
Legal action by media companies forced ReplayTV to remove many features such as automatic commercial skip and the sharing of recordings over the Internet,[11] 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
Many DVRs use the
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
In the UK, digital video recorders are often referred to as "plus boxes" (such as BSKYB's
(ADB).Many satellite, cable and
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.[17] 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.[18] 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
Introduction of dual tuners
In 2003 many Satellite and Cable providers introduced dual-tuner digital video recorders. In the UK,
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).[22]
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.[23]
Types
Integrated television sets
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.
VESA compatibility
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.[24]
Some pay-TV operators provide receivers that allow subscribers to attach their own network-attached storage (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
Linux
There are many
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.[26] 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.
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
There are also several
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, as well as most editions of Windows 7. 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.[29]
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 and video 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 (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 in NTSC, PAL or SECAM 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 pixels 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
DVRs such as TiVo also detect and act upon
Digital sources
Recording digital signals is generally a straightforward capture of the binary
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 (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
Copy protection
The U.S.
DVB
Digital cable and satellite television
Recording satellite television 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 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 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 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
File formats, resolutions and file systems
DVRs can usually record and play
).Some devices can be
Applications
Security
Digital video recorders configured for physical security applications record video signals from closed-circuit television 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
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 optical fiber cable. 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 bussingindividual 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, video monitors.
- 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 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.
- Alarmand 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 or Internet (or any other way) can gather and send real-time data on users' viewing habits.[32] This problem was noted back in 2000[10] and was still considered a problem, specifically with TiVo, in 2015.[33]
Television advertisements
Digital video recorders are also changing the way television programs advertise products. Watching pre-recorded programs allows users to fast-forward through
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.[34] 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.[citation needed]
In 1999, the first DVR which had a built-in commercial skipping feature introduced by
Many[
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).[citation needed] 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
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.
In January 2012,
Patent and copyright litigation
The examples and perspective in this US may not represent a worldwide view of the subject. (December 2010) |
On July 14, 2005,
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.[42]
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.[43] 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.[44] 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".[44]
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
- Home theater PC (Media PC)
- Digital media player
- Smart TV
- Comparison of PVR software packages
- 10-foot user interface
- CRID
- Direct-to-disk recording
- DTE (Direct To Edit)
- DTVPal
- Freeview+
- Freesat+
- Hopper (DVR)
- List of portable software § Recorders
- Media server (Consumer)
- Time shifting
- Space shifting(place shifting)
- Remote storage digital video recorder
- MythTV
- Network video recorder
- SubRip
- Sky+
- Tablo (DVR)
- TiVo
- TV-Anytime
- PVR-resistant advertising
- Remote control
- USB hard disk
- USB On-The-Go
- Vu+
- Video server (Broadcast)
- Kodi (software)
- Xbox One
Notes
- ^ "USER-Digital Video Recorder Or Personal Video Recorder". ShenZhen USER Special Display Technologies, Co., Ltd. Archived from the original on 2014-05-02. Retrieved 2017-04-10.
- ^ "DVR Prototype, Stanford University". 1998-10-01.
- ^ "Effective Memory Use in a Media Server", Edward Y. Chang and Hector Garcia-Molina, Proceedings of the 23rd Very Large Data Base (VLDB) Conference, p.496-505, Athene Greece, 1998.
- ^ "MEDIC: A Memory & Disk Cache for Multimedia Clients", Edward Y. Chang and Hector Garcia-Molina, IEEE International Conference on Multimedia Computing and Systems, p.493-99, Florence, Italy, June 1999.
- ^ "CS448, Experiments in Digital Television". Computer Graphics at Stanford University. Fall 1998. Archived from the original on Oct 31, 2023.
- ^ "What is a PVR?". wiseGEEK. Archived from the original on Apr 25, 2017. Retrieved 2017-04-10.
- ^ "Happy Blue Moon! TiVo celebrates its birthday (a little early)". TiVo Blog. March 22, 2012. Archived from the original on 2019-12-17. Retrieved 2019-12-17.
- ^ "ReplayTV Wins CES 1999 'Best of Show' Award". Business Wire. Find Articles. Jan 6, 1999. Archived from the original on Dec 28, 2011. Retrieved 2011-11-21.
- ^ Markoff, John (1998-11-09). "Netscape Pioneer to Invest in Smart VCR". The New York Times. Archived from the original on Sep 29, 2013. Retrieved 2011-11-21.
- ^ Advertising Age. Archivedfrom the original on 3 Apr 2024.
- ^ Taub, Eric A. (2003-07-21). "ReplayTV's New Owners Drop Features That Riled Hollywood". The New York Times. Archived from the original on Sep 29, 2013. Retrieved 2011-11-21.
- ^ "Digital Video Recorders What are they and where they are going?". Tom Zonts. INFO 300. Archived from the original on 2014-05-02. Retrieved 2017-04-10.
- ^ "WebTV Networks and EchoStar Communications Introduce First Internet TV Satellite Product and Service". Microsoft.com. 1999-01-07. Archived from the original on 2009-02-21. Retrieved 2011-11-21.
- ^ Stephen Manes, 06.11.01, 12:00 AM ET (2001-06-11). "Forbes". Retrieved 2011-11-21.
{{cite news}}
: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link) - ^ "Judge Stops Countersuit against TiVo". SatelliteGuys.US. Archived from the original on 2008-12-06. Retrieved 2011-11-21.
- ^ "From recordable Freeview to YouView in a decade". 30 September 2012.
- ^ Wildstrom, W. H., An Early Independence Day, archived from the original on 2007-07-05
- ^ "FCC Press Release". Fcc.gov. Retrieved 2011-11-21.
- ^ "Turn iPhone and iPad, PC, tablet and smartphone Android into a PVR TV Wi.TV – TELE System Digital Srl". TELE System.
- ^ "Digitenne and CanalDigitaal live TV across your home". vboxcomm.com.
- ^ "Sky's second PVR to debut by March 2001". 12 September 2000. Archived from the original on 2017-04-07.
- ^ Manual of a PVR which can record 2 programs and watch a third if only 2 multiplexes used; see section 3.5.2: watching television while dual recording Archived 2014-04-26 at the Wayback Machine Retrieved 2014-04-25.
- ^ a b Battaglio, Stephen. "Why the New Shows Aren't Working" TV Guide; October 18, 2010; Pages 6–7
- ^ "Most anticipated tech of 2014 (pictures)". CNET. CBS Interactive. Archived from the original on 2014-03-22. Retrieved 2014-03-13.
- ^ "The XBMC Live TV and PVR/DVR Setup Guide". xbmc Media Centre. 2013-07-03. Retrieved 9 December 2013.
- ^ "What's Next for SageTV Customers Post-Google?". GeekTonic. 2011-06-21. Retrieved 2011-11-21.
- ^ Please note: Yahoo! Go for TV currently is only available inside the U.S., for Windows-based systems. Yahoo! Connected TV. Yahoo! Connected TV. Retrieved 09 December 2013
- ^ "turn your PC into a powerful DVD video recorder" … "recording and capturing digital video from digital TV", Media Release, October 1st, 2007 Archived 2016-04-13 at the Wayback Machine. Leadtek. Retrieved 09 December 2013
- ^ Getting Windows Media Center on Windows 8 bought through DreamSpark. Windows. Retrieved 9 December 2013
- ^ "Questions about copy protection – TiVo". Support.tivo.com. 2009-06-23. Archived from the original on 2012-07-18. Retrieved 2011-11-21.
- ^ "Differo – Telememory". Differo.es. Archived from the original on 2011-09-23. Retrieved 2011-11-21.
- ^ Martin, David: "TiVo's Data Collection and Privacy Practices." Archived 2011-09-28 at the Wayback Machine 26 March 2001. Last Viewed 18 September 2007.
- ^ "Using TiVo? Your personal choices may be going straight to advertisers". Los Angeles Times. November 6, 2015.
- ^ "Digital Video Recorders". Archived from the original on 2014-05-02. Retrieved 2017-04-10.
- ^ "1999 Consumer Electronics Show - Las Vegas". hometheaterhifi.com. Retrieved 2023-06-11.
- ^ Jenkins, Henry. "Convergence Culture: Where Old and New Media Collide. Buying Into American Idol". (p. 66–67)
- ^ Young, Susan (2009-04-28). "Devotees delay 'Lost' passion". Variety. Retrieved 2009-04-29.
- ^ Lucas, Amy. "DIRECTV Chooses NDS Dynamic™ to Support Addressable Advertising". Corporate Communications. NDS. Archived from the original on 26 July 2011. Retrieved 3 April 2011.
- S2CID 145337108.
- ^ Jeffrey, Don (June 5, 2012). "Dish's Ad-Skip Tool May Benefit From Cablevision DVR Case". Bloomberg. Retrieved June 5, 2012.
- ^ "Home | Asure Software". Forgent.com. Archived from the original on January 14, 2006. Retrieved November 21, 2011.
- ^ "Home | Asure Software" (PDF). Forgent.com. Archived from the original (PDF) on May 25, 2019. Retrieved November 21, 2011.
- ^ "AOL TV". Pvrwire.com. Archived from the original on 2009-01-16. Retrieved 2011-11-21.
- ^ a b Stelter, Brian (August 5, 2008). "A Ruling May Pave the Way for Broader Use of DVR". The New York Times. Retrieved May 1, 2010.
References
- Free-to-Air Television and other PVR Challenges in Europe Archived 2006-09-27 at the European broadcasting union