A TV tuner card is a kind of

television tuner A tuner is a subsystem that receives radio frequency (RF) transmissions, such as FM broadcasting, and converts the selected carrier frequency and its associated bandwidth into a fixed frequency that is suitable for further processing, usually be ...

that allows

television Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...

signals to be received by a computer. Most TV tuners also function as

video capture Video capture is the process of converting an analog video signal—such as that produced by a video camera, DVD player, or television tuner—to digital video and sending it to local storage or to external circuitry. The resulting digital data ar ...

cards, allowing them to record

television program Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertising, ...

s onto a hard disk much like the digital video recorder (DVR) does. The interfaces for TV tuner cards are most commonly either PCI

bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...

expansion card In computing, an expansion card (also called an expansion board, adapter card, peripheral card or accessory card) is a printed circuit board that can be inserted into an electrical connector, or expansion slot (also referred to as a bus sl ...

or the newer PCI Express (PCIe) bus for many modern cards, but PCMCIA, ExpressCard, or

USB Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad ...

devices also exist. In addition, some

video card A graphics card (also called a video card, display card, graphics adapter, VGA card/VGA, video adapter, display adapter, or mistakenly GPU) is an expansion card which generates a feed of output images to a display device, such as a computer mo ...

s double as TV tuners, notably the

ATI Ati or ATI may refer to: * Ati people, a Negrito ethnic group in the Philippines **Ati language (Philippines), the language spoken by this people group ** Ati-Atihan festival, an annual celebration held in the Philippines *Ati language (China), a ...

All-In-Wonder series. The card contains a tuner and an

analog-to-digital converter In electronics, an analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a digital signal. An ADC may also provide ...

(collectively known as the analog front end) along with demodulation and interface logic. Some lower-end cards lack an onboard processor and, like a Winmodem, rely on the system's CPU for demodulation.

Types

There are many types of tuner cards.

Analog tuners

Analog television cards output a raw video stream, suitable for real-time viewing but ideally requiring some sort of video compression if it is to be recorded. Some cards also have analog input ( composite video or

S-Video S-Video (also known as separate video, Y/C, and erroneously Super-Video ) is an analog video signal format that carries standard-definition video, typically at 525 lines or 625 lines. It encodes video luma and chrominance on two separate chan ...

) and many also provide a

radio tuner A tuner is a subsystem that receives radio frequency (RF) transmissions, such as FM broadcasting, and converts the selected carrier frequency and its associated bandwidth into a fixed frequency that is suitable for further processing, usually be ...

. An early example was the Aapps Corp. ''MicroTV'' for

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ' ...

Macintosh II The Macintosh II is a personal computer designed, manufactured, and sold by Apple Computer from March 1987 to January 1990. Based on the Motorola 68020 32-bit CPU, it is the first Macintosh supporting color graphics. When introduced, a basic sy ...

, which debuted in 1989. More-advanced TV tuners encode the signal to

Motion JPEG Motion JPEG (M-JPEG or MJPEG) is a video compression format in which each video frame or interlaced field of a digital video sequence is compressed separately as a JPEG image. Originally developed for multimedia PC applications, Motion JPEG ...

MPEG The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by ISO and IEC that sets standards for media coding, including compression coding of audio, video, graphics, and genomic data; and transmission and f ...

, relieving the main CPU of this load.

Digital tuners

Hybrid tuners

A hybrid tuner has one tuner that can be configured to act as an analog tuner or a digital tuner. Switching between the systems is fairly easy, but cannot be done immediately. The card operates as a digital tuner or an analog tuner until reconfigured.

Combo tuners

This is similar to a hybrid tuner, except there are two separate tuners on the card. One can watch analog while recording digital, or vice versa. The card operates as an analog tuner and a digital tuner simultaneously. The advantages over two separate cards are cost and utilization of expansion slots in the computer. As many regions around the world convert from analog to digital broadcasts, these tuners are gaining popularity. Like the analog cards, the Hybrid and Combo tuners can have specialized chips on the tuner card to perform the encoding, or leave this task to the CPU. The tuner cards with this 'hardware encoding' are generally thought of as being higher quality. Small USB tuner sticks have become more popular in 2006 and 2007 and are expected to increase in popularity. These small tuners generally do not have hardware encoding due to size and heat constraints. While most TV tuners are limited to the

radio frequencies Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper ...

and

video Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) syst ...

formats used in the country of sale, many TV tuners used in computers use

DSP DSP may refer to: Computing * Digital signal processing, the mathematical manipulation of an information signal * Digital signal processor, a microprocessor designed for digital signal processing * Yamaha DSP-1, a proprietary digital signal ...

, so a firmware upgrade is often all that's necessary to change the supported video format. Many newer TV tuners have flash memory big enough to hold the firmware sets for decoding several different video formats, making it possible to use the tuner in many countries without having to flash the firmware. However, while it is generally possible to flash a card from one analog format to another due to the similarities, it is generally not possible to flash a card from one digital format to another due to differences in decode logic necessary.

Radio tuners

Many TV tuners can function as FM radios; this is because there are similarities between broadcast television and FM radio. The FM radio spectrum is close to (or even inside) that used by VHF terrestrial TV broadcasts. And many

broadcast television systems Broadcast television systems (or terrestrial television systems outside the US and Canada) are the encoding or formatting systems for the transmission and reception of terrestrial television signals. Analog television systems were standardized b ...

around the world use FM audio. So listening to an FM radio station is simply a case of configuring existing hardware.

Mobile TV adapter

External TV tuner card attachments are available for

mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whi ...

handset A handset is a component of a telephone that a user holds to the ear and mouth to receive audio through the receiver and speak to the remote party using the built-in transmitter. In earlier telephones, the transmitter was mounted directly on ...

s like the iPhone, for watching

mobile TV Mobile television is television watched on a small handheld or mobile device. It includes service delivered via mobile phone networks, received free-to-air via terrestrial television stations, or via satellite broadcast. Regular broadcast stand ...

, via

TV station A television station is a set of equipment managed by a business, organisation or other entity, such as an amateur television (ATV) operator, that transmits video content and audio content via radio waves directly from a transmitter on the earth ...

s on 1seg in Japan (

SoftBank is a Japanese multinational conglomerate holding company headquartered in Minato, Tokyo which focuses on investment management. The Group primarily invests in companies operating in technology, energy, and financial sectors. It also runs the Vi ...

), and for soon for the proprietary subscription-based MediaFLO in the U.S. ( Qualcomm). There is also a "converter" for watching DVB-H in Europe and elsewhere via

WiFi Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio wa ...

streaming video ( PacketVideo).

Video capture

Video capture Video capture is the process of converting an analog video signal—such as that produced by a video camera, DVD player, or television tuner—to digital video and sending it to local storage or to external circuitry. The resulting digital data ar ...

cards are a class of video capture devices designed to plug directly into expansion slots in personal computers and servers. Models from many manufacturers are available; all comply with one of the popular host bus standards including PCI, newer PCI Express (PCIe) or AGP bus interfaces. These cards typically include one or more

software driver In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabling operating systems and o ...

s to expose the cards' features, via various

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...

s, to software applications that further process the video for specific purposes. As a class, the cards are used to capture baseband analog composite video,

, and, in models equipped with tuners, RF modulated video. Some specialized cards support digital video via digital video delivery standards including Serial Digital Interface (SDI) and, more recently, the emerging

HDMI High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controlle ...

standard. These models often support both standard definition (SD) and high definition (HD) variants. While most PCI and PCI-Express capture devices are dedicated to that purpose, AGP capture devices are usually included with the graphics adapted on the board as an all-in-one package. Unlike

video editing Video editing is the manipulation and arrangement of video shots. Video editing is used to structure and present all video information, including films and television shows, video advertisements and video essays. Video editing has been dramatical ...

cards, these cards tend to not have dedicated hardware for processing video beyond the

analog-to-digital conversion In electronics, an analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a digital signal. An ADC may also provi ...

. Most, but not all, video capture cards also support one or more channels of audio. New technologies allow PCI-Express and HD-SDI to be implemented on video capture cards at lower costs than before. An early example is the Mass Microsystems ''Colorspace FX'' card from 1989.InfoWorld - Jan 30, 1989
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Applications

There are many applications for video capture cards like EasyCap including converting a live analog source into some type of analog or digital media, (such as a VHS tape to a

DVD The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind ...

), archiving, video editing, scheduled recording (such as a DVR), television tuning, or video surveillance. The cards may have significantly different designs to optimally support each of these functions. Capture cards can be used for recording a

video game Video games, also known as computer games, are electronic games that involves interaction with a user interface or input device such as a joystick, controller, keyboard, or motion sensing device to generate visual feedback. This fee ...

longplay (LP) so gamers can make walkthrough

gameplay Gameplay is the specific way in which players interact with a game, and in particular with video games. Gameplay is the pattern defined through the game rules, connection between player and the game, challenges and overcoming them, plot and pl ...

videos. One of the most popular applications for video capture cards is to capture video and audio for live Internet video streaming. The live stream can also be simultaneously archived and formatted for

video on demand Video on demand (VOD) is a media distribution system that allows users to access videos without a traditional video playback device and the constraints of a typical static broadcasting schedule. In the 20th century, broadcasting in the form of ...

. The capture cards used for this purpose are typically purchased, installed, and configured in host PC systems by hobbyists or systems integrators. Some care is required to select suitable host systems for video encoding, particularly HD applications which are more affected by CPU performance, number of

CPU core A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ...

s, and certain motherboard characteristics that heavily influence capture performance.

References

{{Reflist

External links

"PC Project: Choosing a TV tuner card to record digital TV"
pcauthority.com.au, Retrieved 9 January 2011 Computing input devices Set-top box Television technology