What is HDMI?

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HDMI is a Data cable used in A/V equipment for transmission of video and audio. It is a digital transmission as opposed to an analog one. HDMI has been evolving so you may find different answers but in it’s current incarnation HDMI is capable of higher than HD resolution video, uncompressed 8 channel audio, control functions and greater color range. HDMI cable vary greatly in price. Some of that has to do with marketing hype but it isn’t something to skimp on. Some people say there is no difference between an expensive cable and a cheap one for quality of picture but usually they are wrong. HDMI is prone to signal loss and timing error of longer lengths of cable more so than analog cables are. Also cheaper cables often have earlier specs on HDMI and don’t have the bandwidth to carry all the newer features. You wouldn’t have noticed if you were hooking up an HD cable box because it isn’t 1080P and doesn’t have HD audio anyway but you would notice on a Blu-Ray player. Hope this helps.

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What Is HDMI Cable Used for

High Definition Multimedia Interface (HDMI) cables are the primary cables used to transmit high definition digital video and audio to various types of visual media.

    History

  1. HDMI technology was first released to the market in December 2002. This was around the same time that high definition technology for televisions first hit the market. HDMI cables were developed to reduce the amount of cords necessary to transmit both digital video and digital audio to HD-capable devices.
  2. Function

  3. HDMI cables take uncompressed digital video and audio from an HD capable source such as a Blu-Ray player or HD capable digital cable box and allow them to be displayed on HDTVs.
  4. Benefits

  5. HDMI cables allow a user to get both video and audio to an HDTV without the need to use multiple cables. This is an improvement over DVI cables which only transmit video.
  6. Considerations

  7. As the length of HDMI cable increases, there is an increased risk of signal degradation. For instance, most HDMI cables are unable to transmit true 1080p resolution signal beyond distances of 50 feet. HDMI version 1.3 which offers support for Deep Color, has a signal degradation range of less than 20 feet.
  8. Fun Fact

  9. PCs can be attached to HDTVs if the PC contains a graphics card with a DVI port and a DVI to HDMI cable is used.

Read more: What Is HDMI Cable Used for? | eHow.com http://www.ehow.com/facts_5405477_hdmi-cable-used.html#ixzz15hmgwVnM

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HDMI (High-Definition Multimedia Interface) is a compact audio/video interface for transmitting uncompressed digital data.[1] It represents a digital alternative to consumer analog standards, such as radio frequency (RF) coaxial cable, composite video, S-Video, SCART, component video, D-Terminal, or VGA. HDMI connects digital audio/video sources—such as set-top boxes, upconvert DVD players, HD DVD players, Blu-ray Disc players, AVCHD camcorders, personal computers (PCs), video game consoles such as the PlayStation 3, Xbox 360, and AV receivers—to compatible digital audio devices, computer monitors, video projectors, and digital televisions.[1]

HDMI supports, on a single cable, any uncompressed TV or PC video format, including standard, enhanced, and high-definition video; up to 8 channels of compressed or uncompressed digital audio; and a Consumer Electronics Control (CEC) connection. The CEC allows HDMI devices to control each other when necessary and allows the user to operate multiple devices with one remote control handset.[2] Because HDMI is electrically compatible with the signals used by Digital Visual Interface (DVI), no signal conversion is necessary, nor is there a loss of video quality when a DVI-to-HDMI adapter is used.[3] As an uncompressed connection, HDMI is independent of the various digital television standards used by individual devices, such as ATSC and DVB, as these are encapsulations of compressed MPEG video streams (which can be decoded and output as an uncompressed video stream on HDMI). The HDMI standard was not designed to include passing closed caption data (for example, subtitles) to the television for decoding.[4] As such, any closed caption stream has to be decoded and included as an image in the video stream(s) prior to transmission over an HDMI cable to be viewed on the DTV. This limits the caption style (even for digital captions) to only that decoded at the source prior to HDMI transmission. This also prevents closed captions when transmission over HDMI is required for upconversion.

HDMI products started shipping in late 2003.[5] Over 850 consumer electronics and PC companies have adopted the HDMI specification (HDMI Adopters).[6][7][8] In Europe, either DVI-HDCP or HDMI is included in the HD ready in-store labeling specification for TV sets for HDTV, formulated by EICTA with SES Astra in 2005. HDMI began to appear on consumer HDTV camcorders and digital still cameras in 2006.[9][10][11][12][13] Shipments of HDMI were expected to exceed that of DVI in 2008, driven primarily by the consumer electronics market.[14][15]

http://en.wikipedia.org/wiki/HDMI

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Built in ATSC/QAM digital/NTSC analog tuner

Answer

An NTSC/ATSC/QAM digital tuner, in the case of a TV, means that the TV supports the NTSC, ATSC, and QAM broadcast standards with its included tuner. NTSC is the old analog over-the-air (OTA) standard, ATSC is the newer digital over-the-air supporting High Definition video and Dolby Digital AC3 audio, and QAM means that the TV can decode digital cable signals without a set-top box.

My internet research indicates that QAM will receive unencrypted broadcasts only. While encrypted channels varies by geography, it seems that most cable stations are encrypted while major networks are not. So, best I’ve determined, is that if you want more than just the major networks in high def you still need the set-top box or Cablecard.

From Wikipedia, the free encyclopedia

Jump to: navigation, search

Multiple MPEG programs are combined then sent to a transmitting antenna. In the US broadcast digital TV system, an ATSC receiver then decodes the TS and displays it on a TV.

An ATSC (Advanced Television Systems Committee) tuner, often called an ATSC receiver or HDTV tuner, allows reception of ATSC digital television (DTV) signals broadcast over-the-air by TV stations in North America, parts of Central America and South Korea. Such tuners may be integrated into the television, VCR, digital video recorder, and set-top box which provides audio/video output-connectors of various types.

Contents

[hide]

//

[edit] Technical overview

The terms “tuner” and “receiver” are used loosely, and it is perhaps more appropriately called an ATSC receiver, with the tuner being part of the receiver (see Metonymy). The receiver generates the audio and video (AV) signals needed for television, and performs the following tasks: demodulation, error correction, MPEG transport stream demultiplexing, decompression, AV synchronization, and media reformatting to match what is optimal input for one’s TV. Examples of media reformatting include: interlace to progressive scan or vice versa, picture resolutions, aspect ratio conversions (16:9 to or from 4:3), frame rate conversion, even scaling. Zooming is an example of resolution change. It is commonly used to convert a low-resolution picture to a high-resolution display. This lets the user eliminate letterboxing or pillarboxing by stretching or cropping the picture. Some ATSC receivers, mostly those in HDTV sets, will stretch automatically, either by detecting black bars, or reading the Active Format Descriptor.

[edit] How an ATSC Tuner Works

An ATSC tuner works by generating audio and video signals that are picked up from over-the-air TV broadcasts. ATSC tuners provide the following functions: selective tuning, demodulation, transport stream demultiplexing, decompression, error correction, analog-to-digital conversion, AV synchronization and media reformatting to fit the specific type of TV screen optimally.

Selective tuning
Selective tuning is the process by which an RF channel is selected by a receiver from within a band of transmitted RF signals. The tuner usually performs the function of frequency-agile selection, along with rejection of unwanted out-of-band signals.
Demodulation
Demodulation means transforming the signal from the tuner into a usable signal that a TV set can use to produce quality images and sound without further consideration for the frequency at which it was transmitted. It is separation of a standard baseband signal from the RF carrier that was used to transmit it through the air (or down a coaxial cable or other long-distance medium.)
Transport-stream demultiplexing
In the US, multiple digital signals are combined and then transmitted from one antenna source to create over the air broadcasts. By the reverse process, an ATSC receiver first receives the combined MPEG transport stream and then decodes it to display one of its component signals on a TV set. (In principle, more than one signal within the same transport stream could be decoded by one receiver and displayed on multiple TV sets or as picture-in-picture on a single set, with only one Selective Tuning and Demodulation block.)
Decompression
Since digital signals that are broadcast over the air are compressed (packed smaller), once they are received by the ATSC tuner, these compressed packets of digital data are then decompressed (unpacked to their original size). The ATSC system uses lossy compression, so while the decompressed data size is the same as the original compressed data size, the data produced is not exactly the same as the original data fed into the system at the transmitting site, but it is close enough that most people don’t notice much degradation in the picture and sound.
Error correction
Error correction is a technology that is used by the ATSC tuner to make sure that any data that is missing can be corrected. For instance, sometimes interference or a poor-quality signal will cause the loss of some data that the ATSC tuner receives. With error correction, the tuner has the ability to perform a number of checks and repair data so that a signal can be viewed on a TV set. Error correction works by adding to the signal before transmission some extra information that can be used upon reception to fill in gaps. Therefore, error correction has the opposite effect of compression–it increases the amount of data to transmit, rather than reducing it like compression does, and it improves the quality and robustness of the signal rather than reducing it. Compression removes redundant (and some non-redundant) data, while error correction adds some redundant data. The reason for using error correction rather than just using less compression and keeping the redundancy that was already there is that error correction systems are specially designed to get the maximum benefit out of a very small amount of redundant data, whereas the natural redundancy of the data doesn’t do this job as efficiently, so with error correction the net amount of data needed is still smaller.

  • There is a subsection in the ATSC standard (ATSC-E) that allows broadcasters to add extra (and variable types) of error correction to their broadcast streams.
  • This error correction service is not mandatory in the US, nor is it mandatory in Canada.
  • It is not known how many HDTV receivers support this error correction standard.
  • For the transmission of HDTV at 720 or 1080, an extra 1% to 3% added error correction codes will help reduce some of ATSC’s poorer performance with weak signals under adverse multipath conditions.
  • Reception is greatly reduced due to EMI in the shortwave to VHF and UHF bandwidth from nearby computers of all sorts [light], portable WiFi and Broadband internet , microwave ovens [burst while activated], cell phones and the towers they communicate with, and even power lines with electronic {00100} transmissions.
AV synchronization
AV synchronization is the coordination of audio and video signals being displayed on a digital TV in proper time. AV synchronization ensures that the audio does not lag behind the video that is being displayed on the TV set or vice versa, so that both audio and video are in sync.
Image reformatting
Media reformatting is extremely important because the formatting of images on TV sets differs significantly according to the technology employed. For instance, some televisions have an interlaced picture, whereas others have a progressive-scan picture. Different televisions have a different aspect ratio.

Answer

An NTSC/ATSC/QAM digital tuner, in the case of a TV, means that the TV supports the NTSC, ATSC, and QAM broadcast standards with its included tuner. NTSC is the old analog over-the-air (OTA) standard, ATSC is the newer digital over-the-air supporting High Definition video and Dolby Digital AC3 audio, and QAM means that the TV can decode digital cable signals without a set-top box.

My internet research indicates that QAM will receive unencrypted broadcasts only. While encrypted channels varies by geography, it seems that most cable stations are encrypted while major networks are not. So, best I’ve determined, is that if you want more than just the major networks in high def you still need the set-top box or Cablecard.***

From Wikipedia, the free encyclopedia

Jump to: navigation, search

Multiple MPEG programs are combined then sent to a transmitting antenna. In the US broadcast digital TV system, an ATSC receiver then decodes the TS and displays it on a TV.

An ATSC (Advanced Television Systems Committee) tuner, often called an ATSC receiver or HDTV tuner, allows reception of ATSC digital television (DTV) signals broadcast over-the-air by TV stations in North America, parts of Central America and South Korea. Such tuners may be integrated into the television, VCR, digital video recorder, and set-top box which provides audio/video output-connectors of various types.

Contents

[hide]

//

[edit] Technical overview

The terms “tuner” and “receiver” are used loosely, and it is perhaps more appropriately called an ATSC receiver, with the tuner being part of the receiver (see Metonymy). The receiver generates the audio and video (AV) signals needed for television, and performs the following tasks: demodulation, error correction, MPEG transport stream demultiplexing, decompression, AV synchronization, and media reformatting to match what is optimal input for one’s TV. Examples of media reformatting include: interlace to progressive scan or vice versa, picture resolutions, aspect ratio conversions (16:9 to or from 4:3), frame rate conversion, even scaling. Zooming is an example of resolution change. It is commonly used to convert a low-resolution picture to a high-resolution display. This lets the user eliminate letterboxing or pillarboxing by stretching or cropping the picture. Some ATSC receivers, mostly those in HDTV sets, will stretch automatically, either by detecting black bars, or reading the Active Format Descriptor.

[edit] How an ATSC Tuner Works

An ATSC tuner works by generating audio and video signals that are picked up from over-the-air TV broadcasts. ATSC tuners provide the following functions: selective tuning, demodulation, transport stream demultiplexing, decompression, error correction, analog-to-digital conversion, AV synchronization and media reformatting to fit the specific type of TV screen optimally.

Selective tuning
Selective tuning is the process by which an RF channel is selected by a receiver from within a band of transmitted RF signals. The tuner usually performs the function of frequency-agile selection, along with rejection of unwanted out-of-band signals.
Demodulation
Demodulation means transforming the signal from the tuner into a usable signal that a TV set can use to produce quality images and sound without further consideration for the frequency at which it was transmitted. It is separation of a standard baseband signal from the RF carrier that was used to transmit it through the air (or down a coaxial cable or other long-distance medium.)
Transport-stream demultiplexing
In the US, multiple digital signals are combined and then transmitted from one antenna source to create over the air broadcasts. By the reverse process, an ATSC receiver first receives the combined MPEG transport stream and then decodes it to display one of its component signals on a TV set. (In principle, more than one signal within the same transport stream could be decoded by one receiver and displayed on multiple TV sets or as picture-in-picture on a single set, with only one Selective Tuning and Demodulation block.)
Decompression
Since digital signals that are broadcast over the air are compressed (packed smaller), once they are received by the ATSC tuner, these compressed packets of digital data are then decompressed (unpacked to their original size). The ATSC system uses lossy compression, so while the decompressed data size is the same as the original compressed data size, the data produced is not exactly the same as the original data fed into the system at the transmitting site, but it is close enough that most people don’t notice much degradation in the picture and sound.
Error correction
Error correction is a technology that is used by the ATSC tuner to make sure that any data that is missing can be corrected. For instance, sometimes interference or a poor-quality signal will cause the loss of some data that the ATSC tuner receives. With error correction, the tuner has the ability to perform a number of checks and repair data so that a signal can be viewed on a TV set. Error correction works by adding to the signal before transmission some extra information that can be used upon reception to fill in gaps. Therefore, error correction has the opposite effect of compression–it increases the amount of data to transmit, rather than reducing it like compression does, and it improves the quality and robustness of the signal rather than reducing it. Compression removes redundant (and some non-redundant) data, while error correction adds some redundant data. The reason for using error correction rather than just using less compression and keeping the redundancy that was already there is that error correction systems are specially designed to get the maximum benefit out of a very small amount of redundant data, whereas the natural redundancy of the data doesn’t do this job as efficiently, so with error correction the net amount of data needed is still smaller.

  • There is a subsection in the ATSC standard (ATSC-E) that allows broadcasters to add extra (and variable types) of error correction to their broadcast streams.
  • This error correction service is not mandatory in the US, nor is it mandatory in Canada.
  • It is not known how many HDTV receivers support this error correction standard.
  • For the transmission of HDTV at 720 or 1080, an extra 1% to 3% added error correction codes will help reduce some of ATSC’s poorer performance with weak signals under adverse multipath conditions.
  • Reception is greatly reduced due to EMI in the shortwave to VHF and UHF bandwidth from nearby computers of all sorts [light], portable WiFi and Broadband internet , microwave ovens [burst while activated], cell phones and the towers they communicate with, and even power lines with electronic {00100} transmissions.
AV synchronization
AV synchronization is the coordination of audio and video signals being displayed on a digital TV in proper time. AV synchronization ensures that the audio does not lag behind the video that is being displayed on the TV set or vice versa, so that both audio and video are in sync.
Image reformatting
Media reformatting is extremely important because the formatting of images on TV sets differs significantly according to the technology employed. For instance, some televisions have an interlaced picture, whereas others have a progressive-scan picture. Different televisions have a different aspect ratio.

http://en.wikipedia.org/wiki/ATSC_tuner

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