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How HDMI Works

electronics.howstuffworks.com — HDMI is more than a port on the back of a TV (and the often expensive cable that fits inside). It's a set of rules for allowing high-definition electronic devices to communicate.

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  • adamriggins, on 10/21/2007, -0/+66if you have never been to monoprice, look them up. VERY inexpensive HDMI cables (and other cables/connectors too). I would link to them but people would think I was spamming this post.

  • HadleyRille, on 10/10/2007, -1/+3Cool article.
    • ravis31, on 10/10/2007, -0/+1yeah,kept hearing HDMI for long and had no idea how it worked!Thanx for the article
    • willynilly, on 10/10/2007, -0/+2Except for inaccuracies like this:

      "Its resolution, or the number of dots that make up the picture on the screen, was about 704 x 480 pixels."

      Good grief, wrong. Standard definition is 720 x 486. DV decided to lop off six scan lines and yield 720 x 480.
  • MrDo, on 10/10/2007, -8/+631) plug the cable into your computer
    2) plug the cable into your screen
    3) Boot Vista
    4) Enjoy the downscaled image because your screen is not MS approved HDCP capable screen
    • RedHerringHack, on 10/10/2007, -7/+6Yeperoonie Posituniee. Copy Protection Sucks. It's really bad for us do it yourself projector hobbyists. High res HDMI HDCP capable LCD controller boards are almost extinct.
    • Ocelot13, on 10/12/2007, -8/+4my 37" displays at its native res or 1080p...so boo yah?
    • skabyss, on 10/10/2007, -5/+13step 5: get a xp disk and remove vista
      • Altanar, on 10/10/2007, -0/+2step 6: Find out that DRM'd HD video doesn't play in XP.
    • oMeSSiaHo, on 10/10/2007, -1/+6HDCP was made by Intel and Microsoft along with many other companies use it. Also, as far as I know it wont be an issue for a few more years now. By then HDCP will be like DVI, every cheap monitor will have it.
  • OrangeCrush, on 10/10/2007, -3/+591) connect HDMI cable to $xxxx TV and new HD cable box you're paying $xx extra per month for.
    2.) Turn on TV and Cable Box. Wow! What a difference!
    3.) Come back later at turn on TV and cable box only to see a message that your TV is not HDCP compliant.
    4.) Scream WTF!? it was working fine a second ago. $%*#*ing DRM!
    5.) Call cable company, they tell you to just turn the box on and off again which you already did.
    6.) Remember nothing ever really turns "off" anymore and unplug the powerstrip by crawling behind the massive TV stand and breaking your arm in three places to reach it.
    7.) Turn everything back on and wait for the d*mn cable box to do a cold boot. Gee that HD splash screen sure is purtty tho.
    8.) Enjoy the last 7 minutes of the show you were going to watch.
    • KF6BBL, on 10/10/2007, -2/+239) Take all your HDMI cables back to the store for refund, and connect it all with analog component video.
      10) Enjoy the next movie
      11) Profit!
      • Sunsetter, on 10/10/2007, -2/+3"Take all your HDMI cables back to the store for refund, and connect it all with analog component video."

        This is the best line here due to the severe limitations of HDMI. Read this article and you will realize that HDMI won't be around for too long anyway.

        http://www.audioholics.com/education/cables/whats- ...
    • zeroMPHfallover, on 10/10/2007, -1/+12You need calcium.
    • HappyScrappy, on 10/10/2007, -2/+11Step 9. Don't buy a Westinghouse TV (or if you do, make sure it has the latest firmware).
      • foxhoundadmin, on 10/10/2007, -0/+1yah... buy an OLEVIA! they're better than westinghouse (and just as cheap). i hear they're manufactured by samsung, too!
      • simplenation, on 10/10/2007, -0/+3serious question. please answer before you dig me down? How do you update the firmware on an Olevia TV?
        • foxhoundadmin, on 10/10/2007, -0/+5goto their website, download firmware to usb device, plug in said usb device, update (via menu)! :D
    • dafragsta, on 10/10/2007, -11/+2Did you blank out prices or did Digg do that? Seriously, what's the point of that? This isn't a ***** retail website, it's a social networking site, so if we wanna talk about prices we should be able to.
      • marx2k, on 10/10/2007, -1/+0That's an unfunny joke, right?
        • dafragsta, on 10/10/2007, -2/+2The overempahsized sense of outrage, but no, why did Digg blank out the prices?
        • arjie, on 10/10/2007, -0/+1I do no think it was the digg that dunnit.
    • xdevit, on 10/10/2007, -0/+2On the cable box.. Hold volume up and down.. then hit info to reboot your box.
  • neiltc13, on 10/11/2007, -11/+4Buried as misleading as yet again a site tries to convince people that 16:9 TV is only available in HD.
  • nonpareil, on 10/10/2007, -1/+3I just bought this one (http://www.amazon.com/HDMI-Feet-Super-Resolution-C ... for like $6 including shipping. Here's hoping it works with the '360.
  • dsmx, on 10/10/2007, -1/+7This whole HD era is completely crap. There so paranoid about people pirating there content that any advantages you gain by going to HD are nullified by the stupid DRM. All the DRM is punish the people who bought the content legally, all the people the DRM was aimed at are unaffected and can watch it on anything they want for free.
    Am I missing something apart from slightly nicer looking shows what possible advantage does it have?
    • SuperSunny, on 10/10/2007, -1/+3Well, it's hard to say. For example, when I watch NBC, ABC, and all that jazz shows, I watch them in HD. Since I began to watch them in HD, I have trouble watching them in normal because my own judgement on quality has increased. My friend brought over a Heroes DVD and we played it on my TV, and it felt like I was watching a piss-poor compressed version of the show, as I'm used to watching it in HD. Everything is just so much more clear. As long as it isn't DRM infected. Same with game consoles. I can't play the 360 on normal TV anymore because I'm used to the wider field of view and clarity given in games by the HD.
    • DarkDx, on 10/10/2007, -9/+2Huh, and a cd is enough, dvd is not needed.
      dvd is enough, bluray/hd-dvd is not needed.
      640k of ram is enough
      16 bits color is enough.
      Go and ***** yourself, pussie.
    • foxhoundadmin, on 10/10/2007, -1/+3also, there's too many standards! 720p/1080i, 1080p... component, dvi, hdcp (ugh)-dvi, hdcp-hdmi... atsc, 64-qam/256-qam, CLEAR qam... hd dvd, blu ray...

      JEEBUS! it's enough to make one's head spin!! :@
      • foxhoundadmin, on 10/10/2007, -0/+2i completely forgot about the different hdmi VERSIONS! oh boy! this just keeps getting better and BETTER!

        i just read the article, and it said, "A new lip-synch feature also reduced that sound and video would fall out of synchronization during playback, making an otherwise immaculate recording look badly-dubbed. Some reports even claimed that any devices that did not have HDMI 1.3 were obsolete."

        HA! HAHA!! OMG!!! y'know what? ***** it! ***** hdmi! ***** hdtv! ***** DIGITAL! i'm going back to crt sdtvs and vcrs! at least THEY worked (and without copy protection)!

        now, where can i find an ntsc crt sdtv these days? :\
    • IllBeBack, on 10/10/2007, -0/+2"slightly nicer looking" ???
      Uhhh, I don't know where you've been getting your HD content from, but to me HD looks WAY nicer looking than SD.
  • Starseed, on 10/10/2007, -2/+2Great article. Thanks for the post!
  • nonposter, on 10/10/2007, -0/+1Some not-so-expensive, decent cables on Amazon: http://www.amazon.com/s/ref=sr_nr_p_3_0/?ie=UTF8&r ...
  • yanked, on 10/10/2007, -1/+10I still want to know why most 1366x768 LCD TVs prevent me from sending more than 1280x720 from computer->DVI->HDMI->TV. Anyone know?
    • Scott802, on 10/10/2007, -0/+5Have you tried a program called Powerstrip? If not google "PowerStrip 3.75 "
    • shredswithpiks, on 10/10/2007, -4/+4because more than 1366x768 cannot fit inside of 1366x768?
      • ultrafez, on 10/10/2007, -0/+2If you hadn't noticed 1280x720 is actually SMALLER than 1366x768, please learn some math before you try and look smart.
    • catalysis, on 10/10/2007, -0/+2Interestingly, when I was using a radeon x800xl, the output to my HDTV was fine. Now that I upgraded to the 2600xt I am having the same problem as you. It must be the way the outputs on the cards are manufactured.
    • totorototoro, on 10/10/2007, -0/+5or SwitchResX or DisplayConfigX if you are on OSX :p
    • yanked, on 10/10/2007, -0/+6Sorry, I should clarify: the problem is not with my computer sending 1366x768 over DVI/HDMI, the problem is that the TV won't recognize anything greater than 1280x720 coming in on the HDMI port. I've used SwitchResX (on OSX) and can send 1366x768 fine; it's the TV that's the issue, and as far as I can tell, this is a common issue with LCD TVs advertising 1366x768. What I don't understand is why TV manufacturers build in this constraint, or if there's any way around it.
  • Ascendancy5, on 10/10/2007, -3/+3These articles are popping up way too much on Digg now.
    • punkisnotdead, on 10/10/2007, -0/+1Well it won't be long before the domain is banned for spamming Digg and then we will be rid of them!
  • Avaseal, on 10/11/2007, -7/+2lawl.. well basically that 1080p picture that you're raving about on your super hifi home theater system...ya, unless you have an HDMI 1.1 cable that is rated for 4.5Gbps then you're not getting that true 1080p picture you keep telling people about. when it comes to HDMI 1.3b (1440p) you're gonna need a spiffy lil HDMI cable that can handle up to 10Gbps..and around 20Gbps (HDMI 1.3c?) if you expect to run 2160p, which isnt out of course but its gonna be the latest and greatest. oh ya and DRM ftl.
  • pigfister, on 10/10/2007, -0/+6it goes something like this, sony and buddies at the mpaa want to control everyone's hardware and cripple everything they can with drm. They delay the ticking bomb so all the old incompatible equipment can be sold then they turn the drm on!

    http://www.boingboing.net/2006/05/23/hdmi-the-manc ...

    quote from link >>> " HDMI, the Manchurian DRM - a Broadcast Flag dormant until 2010
    Posted by Cory Doctorow, May 23, 2006 1:16 AM | permalink
    Hollywood studios and some CE manufacturers have reportedly entered into an informal agreement to hold off on using the "image constraint token" in HDMI DRM until 2010 or 2012. The image constraint token is a flag in a video signal that instructs receivers, DVD players and other high-definition sources to "down-rez" their output to a low-definition signal when connecting to an "untrusted" screen or other sink.

    The effect is that if your screen or recorder isn't blessed by Hollywood, they can limit the video they send to it to a low-resolution image. Manufacturers who want the full signal have to enter into the HDMI license agreement and agree to cripple their hardware in lots of ways -- and have to promise not to make their equipment compatible with anyone else's, unless they, too, agree to cripple their hardware. "

  • diggB, on 10/11/2007, -1/+6One of my greatest pet peeves is going to Best Buy or Circuit City or whatever large consumer electronics store and seeing $80 HDMI Monster cables (or, for that matter, $30 USB or firewire cables). They prey on the ignorance of the consumer who just bought their shiny new Xbox 360 or HDTV. "Oh, you want have HD on your TV in full 1080p? Then let me show you these gold plated cables that will make your HD video that much better ... " Please, for God sake, don't pay over $10 for a f'cking cable! Every time you buy a Monster cable, they kill a kitten! Do it for the kitten!
    • oMeSSiaHo, on 10/11/2007, -1/+3Gasp! A store that wants to make money!! Bastards!
      • arjie, on 10/11/2007, -0/+3Gasp! A consumer who wants to inform other consumers about cheaper alternatives!! Bastard!
  • zdiggler, on 10/10/2007, -2/+7if you have a DVI Cable and you got two DVI to HDMI adapters it will becomes a 100% HDMI cable basically there was nothing wrong with DVI cable from first place. but they wanted to put DRM so they came up with HDMI.

    Highly DRM'ed Multimedia Interface
    • diggB, on 10/10/2007, -0/+6Sorta of. You forgot about the digital audio. Running a SINGLE cable from your component to your TV for both your audio and video is really pretty sweet (no more messy tangle of cables).
      • Burn, on 10/10/2007, -0/+2Sure, if your TV speakers don't suck...but they usually do. External receiver FTW.
        • diggB, on 10/10/2007, -0/+1True. But then many of the newer receivers can accept multiple HDMI inputs from multiple sources. Thus, instead of running both a video cable and an audio cable from your Xbox 360 to your receiver, you can use single HDMI cable to your receiver and then a single HDMI cable to your HDTV. In fact, if you happen to have a Blu-ray player or a series 3 Tivo, then you just need to run an HDMI cable from each to the receiver and then one more to your HDTV. 3 cables! i.e. Sweeeeet!
  • pigfister, on 10/10/2007, -3/+1buried as inaccurate as no mention of hdcp handshake issues that are happening and ppl with out of date warranty are having to pay to make supposed hdcp compatible screens work!
    • MacSuxWindozSux, on 10/10/2007, -0/+1Yeah there are a few errors or vague points.

      The viewing area picture implies that older NTSC cuts off part of the picture on the sides. They only do this with VHS/DVD movies on NTSC screens purposely.
      In reality the NTSC screen shows black bars ar the top and bottom to keep the wide screen aspect ratio, or the image is just squished.

      Also "Extra Processing Power" used to convert from analog to digital. This is a TV. Not a computer. It's too easy for an extra device in back to decode the signal in real time.
      No processing power used. It does however contradict the latest trends to miniaturize/simplify design. And it is less prone to interference.

      I think the main reason for HDMI is HDCP, the copy protection. Otherwise DVI which is used by LCD Monitors would probably have been used.
      It's too easy to make DVI connectors without screws or to even shrink the form factor for small devices, like they did with USB.
    • ArcaneDevice, on 10/10/2007, -0/+1comment dugg down for not being able to read. Handshake issue on page 2 of the article.
  • xqb4dpx, on 10/10/2007, -0/+3HDMI is great, the picture is brilliant, but soon enough my TV started to dislike the DRM that my cable box was sending to my TV, and since my sony TV didn't have the PROPRIETARY software to decode the cool DRM signals, now I have to take up another one of my composite hd plugs. ***** hdmi, ***** DRM. Anti-DRM day is my birthday.
  • Smedley42, on 10/21/2007, -1/+1Does this guy get paid by the word??
    Some good info buried in a lot of useless babble.
  • LinuxGalore, on 10/10/2007, -0/+7HDMI is a stupid technology, a standard DVI connection will do the same (even better).

    1. Little old lady buys a new TV and Video with HDMI connectors after 19 year old sales man says how good it is.
    2. Little old lady plugs TV into Video and gets a message that TV isnt HDMI 2.28 compliant..
    3. Little old lady rings TV manufacturer and gets told to connect TV to router and download update.
    4. Little old lady scratches head "what is a router ?".
    5. Little old lady throws TV in bin and buys a CRT that "just works".
    • rolf, on 10/11/2007, -0/+2Can you tell me where this Little old lady is? I'd like to be nice and take that HDMI TV off her hands since it's such a bother.
    • arjie, on 10/10/2007, -0/+1Why is Little old lady doing that? With her eyesight, she won't be able to make out the difference. Also, I sincerely apologise if you are the said little old lady, but I had an image of a female Yoda doing all that.
  • RallyRocks, on 10/10/2007, -1/+1good writeup about how HDMI works (as usual for Howstuffworks). It's nice to have sites such as theirs which are able to break technical concepts down into layman's terms. They probably still provide a little too much technical detail for people looking to buy into the HDTV market, but for the curious, it's a great resource!
  • Enlightenment, on 10/11/2007, -1/+5Salesman can talk a long line of ***** to steal your money. Bloggers can also talk a long line of ***** too . So here is REAL proof that it is ok to use any cheap brand of cables shorter than 6 feet. When the data rate (screen resolution) and cable length increases, you are more likely to see problems with cheaper cables. This test states "It never pays to buy a Monster cable first", "Even if you're going for the long haul, try a cheaper cable from a reliable vendor first". This information is really for the common person, and not for someone like Bill Gates who can actually burn money in his fireplace and still be rich.

    http://gizmodo.com/gadgets/field-notes/the-truth-a ...
    http://gizmodo.com/gadgets/hdmi-cable-battlemodo/t ...
    http://gizmodo.com/gadgets/top/the-truth-about-mon ...


  • Xorp, on 10/10/2007, -0/+2Another good read: http://www.bluejeanscable.com/articles/whats-the-m ...

    Component was fine, HDMI is just a scam with a pretty name to put DRM on every freaking thing we buy.
  • digits12, on 10/10/2007, -2/+0Boot Vista
  • Enlightenment, on 10/11/2007, -0/+1http://www.cdfreaks.com/news/Optical-fibers-to-tra ...

    Optical fibers to transmit HDMI and USB Signals
    According to a news published at Tech-On, Pioneer Corporation has developed a signal converter that can bi-directionally transmit not only HDMI and DVI signals but also USB, RS-232C and analog audio signals through a single optical fiber by multiplexing the signals. Signals can be transferred at high distances (300m according the news). There are not yet details about marketing schedule of this product nor about prices (nor about if this device will contain other DRM stuff...)

  • edric9, on 05/26/2008, -0/+0http://www.genericsmed.com
    http://www.generics.ws
  •  

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