What is HDMI®?

R. Kayne

HDMI® (High-Definition Multimedia Interface) is an interface standard used for audiovisual equipment, such as high-definition television and home theater systems. With 19 wires wrapped in a single cable that resembles a USB wire, the cable is able to carry a bandwidth of 5 gigabits per second (Gbps). This is more than twice the bandwidth needed to transmit multi-channel audio and video, future-proofing the interface for some time to come. This and several other factors make HDMI® much more desirable than its predecessors, component video, S-Video, and composite video.

A HDMI® cable.
A HDMI® cable.

Signals that travel through the HDMI® interface are uncompressed and all-digital, while the previous interfaces were all analog. With an analog interface, a clean digital source is translated into less precise analog, sent to the television, then converted back to a digital signal to display on screen. At each translation, the digital signal loses integrity, resulting in some distortion of picture quality. HDMI® preserves the source signal, eliminating analog conversion to deliver the sharpest, richest picture possible.

Used in most modern HDTVs, the high definition video devices are connected through HDMI® cables.
Used in most modern HDTVs, the high definition video devices are connected through HDMI® cables.

Previous video interfaces required separate audio cables, with the vast majority of people using standard RCA L/R analog audio jacks. HDMI®, with its abundant bandwidth and speed, carries not only video but also up to eight digital audio channels for uncompromised surround-sound. It replaces the tangle of wires behind the system with a single cable, greatly simplifying the entire setup process of the home theater system while delivering top tier performance.

Though standard HDMI® or "Type A" has 19 wires, "Type B" will have 29 wires. The latter is targeted for the motion picture industry and other professional applications. Both varieties are "Intelligent HDMI®," referring to the built-in capability for components to talk to each other via the interface. Auxiliary information can provide all-in-one remote functionality and other interoperable features not possible in previous interface technologies.

This interface supports standard video formats, enhanced video, and high-definition. It is also backward compatible with DVI (Digital Video Interface). High-end graphics cards featuring a DVI port can connect to the interface via a DVI/HDMI® cable. This is simply a cable with a DVI connector on one end and a HDMI® connector on the other. As a rule, cables should not run longer than 15 feet (5 meters), or degradation of the signal could occur.

Most modern television sets are sold with at least one HDMI® interface. Some experts advise that two interfaces will provide more flexibility, and for those who want to connect a game console, Blu-ray™ player, or other device, three might serve better. Multiple interfaces are likely become common on digital TVs as the industry incorporates this interface into more peripheral components.

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Discussion Comments


I think if you want to buy a cheap and high quality HDMI cable, Hinsung will be a good choice. Hinsung, is short for Shenzhen Hinsung Electronics Co., Ltd. which is a professional cable company in china.


Can an hd receiver (dish network, time warner, etc) stop emitting an hd signal?


I connect my LCD Sony Bravia tv to my new HP laptop through a HDMI cable (for Netflix and Itunes). The picture and sound appear fine for about 10 minutes. After that the tv screen goes black for a few seconds intermittently. Also it starts to lose color. I re-connected the cable and it fixes the problem for a while but then it recurs. Any idea what could be causing this issue?


My TV has no sound when the hdmi is connected to the dish receiver. Please help.


A quick HDMI 101 folks. HDMI (High Definition Multi-media Interface) will take care of all your problems. If you are unfortunate enough to be using RCA jacks then remember this tip: in with RCA out with RCA. It is well worth upgrading to and utilizing the optimal clarity and ease of HDMI on all of you equipment. HDMI in HDMI out.

It is easy and much less wires and the best clearest reception the fine makers of state of the art technology ever came up with. HDMI has no equal.


Just purchased AppleTV and cannot select HDMI2 to operate the device. DISH is connected to HDMI1. Any suggestions? thanks


i have a home theatre system and cable box both with hdmi. i currently have my audio coming out of my home theatre system. now what i would like to do is, hook an hdmi cable from my home theatre system to my cable box just for my sound, and use an rca for picture. will this work if i do that, and if it does, will my sound have better quality than my rca's?


Rainbow Fish Corporation will soon have a fiber optic HDMI cable. it will be up to 300 meter without the need for a repeater.


I was able to solve the HDMI picture without sound issue by going to my converter remote settings (for Comcast Scientific Atlanta type, I hit "Menu" twice) and changed the audio output to HDMI. One would think somebody I spoke to on the phone would have given me this simple fix.


I desperately need help. When my PC is connected with HDMI cable to LG TV it starts to blink or maybe batter words are to pulse. What could be a problem? I downloaded latest driver for my GeForce9800, replaced cable for other one but problem is still the same. On TV picture is perfect.


I have dish sat with r.c.a. jacks to samsung flatscreen, also have blu-ray to tv with r.c.a jacks to 2nd input to tv but picture from blu-ray is only black and white. would hdmi cable from either satbox or blue correct this problem?


is it possible to receive audio using by dvi cable?


All of you folks with HDMI audio problems. Try changing your audio on the TV to PCM only. This works for me.


To comment 32. Make sure you are using the proper version of HDMI cable. You may need version 1.3


This is the answer: plug the cord into the slot where it fits. Love, jimmu


i was wondering, can you hook up your ps3 to the laptop using an HDMI cable? i tried but it didn't work, is that normal? thanks!


All of you who are having problems with audio, I think there are 2 types of HDMI cables. One which transmits both audio and video Signals and the Other whohc transfers only video signals. Please check on that, it might solve your problem.


I have sony bravia 32" LCD TV. I want to connect my laptop to the LCD with HDMI Cable. I have one HDMI cable but i m unable to see the display of laptop on tv screen. What would be the problem.


I have a new lg 42 1080p tv and a dell laptop with vista. My hdmi cable connection has suddenly stopped working. The tv just displays no signal. I purchased a new cable and it did not make a difference. Any suggestions?


I have a Panasonic HD TV, a Samsung Blue Ray DVD player and a Direct tv receiver. I hooked them up to an HDMI switcher. I have video, but no audio. I have made multiple changes on my set up on every piece of equipment, without success. I have connected every piece separate to the switcher and still do not get any sound. Anyone with an idea of what to do? --Fritz


I'm trying to connect an IBM P275 CRT monitor to my HP laptop via a HDMI to DVI cable. I can't get the laptop to display from the HDMI output.

I've used the VGA output on the laptop to connect, but want to be able to switch from the laptop/hdmi to the tower/vga with the built-in input switch on the CRT. Do I have the wrong type of DVI cable?

Monitor is listed as DVI-A, but I don't know if the cable is DVI specific. I believed they were backward compatible (with later DVI formats)


I hooked up the HDMI cable with my TV and digital box, but there was no signal. I had to use those normal colorful wires connecting my TV with the digital box then it worked. Why is that?


I have CRT TV, I bought the cable one end is component the other end is HDMI. In the back of my t.v. has component outlet and in the back of my DVD Player/Recorder has HDMI outlet. I try to hook it up but I only have sound (audio) but then I have no picture (video). Help!


can I use hdmi port for video capturing?


Well this is the problem. i have my HDMI 2 running but the problem is the screen picture. It has different colors to it and i know for a fact it wasn't like this. Is it a cable problem or what? Don't get me wrong -- the features work but the screen pictures are in colors and i want it to be normal black and white.


Hooked up my HDMI output from my computer graphics card, Nvidia geforce 9800 pci express. Works great on the HDTV, but no sound Is this normal? PS3 works the same way and there is sound. please someone answer this :D


Got my HDMI cables online and it shows 1080p, but how is a $200 cable worth it since you can't get any better than 1080p?


how do i connect my aquarium with HDMI to my tv?


How to connect(use) HDMI port in my Sony Bravia S-series?Is there need of any Special HDMI Player? Please give a procedure. --Balaji.


my samsung has 2 HDMI ports. is my tv HD?


I have bought a Samsung LE32A756 TV and connected my HTPC to it via the HDMI connection on the motherboard (motherboard ASUS M3N78-EMH HDMI). Result: no picture, TV message: no signal found.


this is in reply to marvin with picture, no sound.

I had the same problem. purchased hdtv and exchange cable box for hdtv cable box. using hdmi cable had great picture no sound. Check the settings on your cable box remote. Press settings twice, should read current settings. go to audio control, set at fixed no variable. Then go to audio digital out. scroll to hdmi, hit select. you should get picture and sound. don't know how important, but i use the audio l/r just below the hdmi inputs. hope this helps.


I bought a full Hd 1080 46 inch Lcd From samsung and I try to connect my daewoo dvd player through HDMI but every time I search for the device it tell me that the scan was completed,when I switch the inputs to the hdmi 1,2, or 3 there's nothing, I switch HDMI cable thinking I needed another hdmi cable but with no result please help I don't know what to do.


I have a LG HDTV and Have a xbox 360. I have connected the hdmi cable to the back of tv and it is not showing up. Whats the problem?


I bought a new tv and DVD player with HDMI connection. TV is connected to regular antenna. Should I use a HDMI cable for connection of the tv and dvd units? Will it help for a better picture?


I just got an HD cable box that can handle 1080i resolution but when i connect the hdmi wire and attempt to switch to 1080i it tells me that the setting cannot be changed using the hdmi wire. is the problem with wire or the cable box?


I just bought a Dell 2407 1920x1200 LCD Monitor,

it is not HDMI. Am I already obsolete?


I just bought new Dvd recordable with hdmi. I connected it to DVI on TV. It won't show any close caption. Can you help me?



Maybe you need some kind of HDMI converter. To convert one kind of signal to another.


Maybe your Sharp HD TV has some problem.

RE: If your laptop has HDMI port, it means that your computer can output HDMI signal. eg, you can connect your computer to the display that has a HDMI port.

RE:Yeah, the HDMI signal is dependent on the source, not HDMI cable or converter.

RE:"I just bought a HDTV and I have a HD cable box. My receiver doesn't have a HDMI plug, only S connector and component cable. Should I connect the tv to cable with HDMI and use component cables from receiver to cable, or can I only use one? "

Please make sure that your receiver can display high definition signal, such as 720P, 1080P. As you know your HDTV is high definition source, it can only be displayed on the display machine that have ability to display high definition HDTV signal.

RE:"Posted by: khad

I have a HDTV with 2 HDMI slots, a Duel Tuner DVR HD cable box, a HD DVD player, VCR, XBOX 360, WII, and a Surround Sound System, if I use HDMI cables for 2 things does that mean I will not need component cables or HD audio cables or optical digital audio cables for the 2 things I use the HDMI cables for? "

If you choose HDMI output and input, then you only have to use one HDMI cable as the HDMI can transmit both audio and video. If you use other component video source machine, then you can use a HDMI converter to convert the component video to HDMI, you can use HDMI converter from Gefen, Grandbeing, etc.


any answer for the issue of hdmi cable vision no sound- I have the same problem


I have a HDTV with 2 HDMI slots, a Duel Tuner DVR HD cable box, a HD DVD player, VCR, XBOX 360, WII, and a Surround Sound System, if I use HDMI cables for 2 things does that mean I will not need component cables or HD audio cables or optical digital audio cables for the 2 things I use the HDMI cables for?

Also, please tell me the best way to hook up all these things? What type of cables do I need?

Should I use HDMI, S, Digital Optical, and Component cables for each thing or do I only need one?


I just bought a HDTV and I have a HD cable box. My receiver doesn't have a HDMI plug, only S connector and component cable. Should I connect the tv to cable with HDMI and use component cables from receiver to cable, or can I only use one?


If the cable TV signal from the wall in my house is carried on a coaxial cable, hasn't the signal already been down-converted to analog? So the HDMI cable is only good for the connection between the cable box and the TV. Is that correct?


Why buy high dollar HDMI cables when your cable/sat feed comes in on co-ax?


I just bought a coffee maker and it has HDMI...what does that mean? ;)


I just bought a laptop and it has HDMI...what does that mean?


Hi, I just bought a brand new Sharp HD TV. There are 3 inputs for HDMI. I connected the HDMI cable from the cable box to the TV but when I turned on the TV, I get no audio - only a picture. I tried the other slots and same result. Why is that?


Kendinlv: Is your receiver an all in one home theater with a DVD player or is it a stand alone receiver to get surround sound?


If the cable coming from the dish (on the outside of the house) into the dish receiver (box) is a coaxial cable then doesn't that mean that it has been compressed and the quality already diminished?


You can go directly to your TV with you want and get HD.

But, if you use a cable box, the cables from the cable box to the TV sends an analog signal to the TV. Your TV has to reconvert it back to HD which loses some quality. The HDMI cable sends the HD signal directly to TV.


I don't get all this. My signal comes in from the cable company through a coaxial cable, right? It goes to the cable box and then I need some fancy expensive connecting wire to get great picture and sound. But this is the same picture and sound that are originally brought to me by the cable company's coaxial cable. Why can't I just use a coaxial cable from the box to the TV? This whole thing just doesn't make sense.


Can I view closed captions on a HDTV if I connect to cable box with HDMI?


I just bought a HDTV and I have a HD cable box. My receiver doesn't have a HDMI plug, only S connector and component cable. Should I connect the tv to cable with HDMI and use component cables from receiver to cable, or can I only use one?

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