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Displays Hardware Technology

HDMI Brands Don't Matter 399

Posted by timothy
from the but-the-monster-won't-die dept.
adeelarshad82 writes "I'm sure most of us looking for an HDMI cable have been in a situation where a store clerk sidles up, offers to help and points to some of the most expensive HDMI cables — because apparently these are 'superior cables' which we all absolutely need for the best possible home theater experience. Well, as it turns out the claims are, for the vast majority of home theater users, utter rubbish. According to tests ran on five different HDMI cables, ranging in price from less than $5 up to more than $100, HDMI brands really don't matter."
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HDMI Brands Don't Matter

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  • by Anonymous Coward on Saturday May 14, 2011 @02:50PM (#36128358)

    For short cable runs, any old HDMI cable will do. When you get into the 50-100 ft lengths, the cable quality absolutely matters.

    HDMI signals may be digital, so there's none of the subjective analog concerns, but it's also a real-time signal, which makes it susceptible to even small delays in transmission across the cable. This isn't a concern in a sub-20 ft cable, but becomes noticeable in the cheap longer cables.

  • by Anonymous Coward on Saturday May 14, 2011 @02:52PM (#36128368)

    ... but the delays in the cable will be governed by the laws of physics, not by the price of the cable!

  • Real time? (Score:5, Informative)

    by overshoot (39700) on Saturday May 14, 2011 @02:57PM (#36128412)
    No, sorry. 200 ns (flight time for 100 foot cables) is negligible. HDMI doesn't have critical round-trip timing and it's relatively insensitive to skew between conductor groups.

    The only difference between cables that really matters is dispersion (frequency-dependent losses.) A difference of 1 dB/meter in loss between cables is going to make quite a difference at 30 meters. However, I wouldn't bet one way or the other on which brands have better or worse loss characteristics.

  • Denon Gets It (Score:5, Informative)

    by Petersko (564140) on Saturday May 14, 2011 @03:02PM (#36128448)
    This is my favorite cable ever. [denon.com] Denon gets it - idiots want to give their money away, why not make it easy for them?
  • by kevinmenzel (1403457) <kevinmenzel@noSpam.gmail.com> on Saturday May 14, 2011 @03:04PM (#36128482)
    I think the point is more: Either the signal on the cable has distinguishable 0s and 1s, or it doesn't. Which is absolutely how it works. Over long distances, you might have some interference - that EVENTUALLY will lead to a 0 and a 1 not being that different anymore, or at least severely corrupted - but frankly it's entirely different than it was with analog cables, because so long as 0 and 1 are different enough for a given situation - it doesn't matter HOW DIFFERENT they are. Making them MORE different does NOT improve signal quality. Therefore - with HDMI, or any other digital cable - you should buy a cable that is the cheapest that will do the job. A more expensive cable will not improve signal in the situation where the cheaper cable works. A more expensive cable might have better connectors - by which I do NOT mean "plated with gold" I mean "designed in such a way that the cable does not fall apart on repeated unplugging and plugging back in" - so if that's a common use case, by all means, factor that in. If you are in the 0.00001% case where you absolutely need more sheilding around your cable, because there is just SO MUCH damned inteference, or because your cable run just HAS to be 200 un-amped feet over copper... well then, buy the more expensive cable. But there are $300 6-foot HDMI cables out there, with "features" that don't matter one damn, and nobody should be buying them.
  • by gweihir (88907) on Saturday May 14, 2011 @03:10PM (#36128522)

    Actually, gold plating decreases signal quality (by a tiny bit). The thing is that when current flows over changes in conductor material, noise is added. With gold, you usually have other material below, as copper diffuses though gold layered directly on it. So copper-nickel-gold---gold-nickel-copper is actually worse than copper-nickel---nickel-copper. One of the dirty secrets of audio contacts. Not that you could hear the difference.

  • by beelsebob (529313) on Saturday May 14, 2011 @03:11PM (#36128528)

    The point of the article being that many people think that a better cable will give them higher quality video... It won't... It'll give them video at all if a lower quality cable will fail. Not only that, but given that all HDMI cable is required to meet a spec, unless the consumer is doing something out of spec (very very rare), all HDMI cables, including the $1 ones will give them a signal.

  • where i get 'em (Score:4, Informative)

    by Anonymous Coward on Saturday May 14, 2011 @03:23PM (#36128618)

    (i promise i'm not a shill)

    monoprice.com

    they do an awesome job of getting any type of cable i need, at an awesome price.

  • by Coolhand2120 (1001761) on Saturday May 14, 2011 @03:31PM (#36128676)
    About the only thing you said that is true here is that you're not really qualified to speak about it. There are more "checksums, checkbits, res etc" than you can shake a space worm at. See all thoes things that say "bit" and "stream" and "PCM". Ya, all those things have "checksums, checkbits, res etc". What I would really like to know is why you bothered posting when all you had to say was so much garbage? Does it somehow make you feel more important to "educate" people even when what you're saying is at best a guess and at worst totally wrong? I sort of understand HDMI, but you are more of a mystery to me.

    Here's the link to the specifications: [wikipedia.org]
    From the WIKI:

    HDMI uses the Consumer Electronics Association/Electronic Industries Alliance 861 standards. HDMI 1.0 to HDMI 1.2a uses the EIA/CEA-861-B video standard, and HDMI 1.3+ uses the CEA-861-D video standard.[2] The CEA-861-D document defines "video formats and waveforms; colorimetry and quantization; transport of compressed and uncompressed, as well as Linear Pulse Code Modulation (LPCM), audio; carriage of auxiliary data; and implementations of the Video Electronics Standards Association (VESA) Enhanced Extended Display Identification Data Standard (E-EDID)."[42]

    To ensure baseline interoperability between different HDMI-sources and displays (as well as backward compatibility with the electrically compatible DVI standard), all HDMI compliant devices are required to support sRGB video 4:4:4, at 8 bits per component. Support for YCbCr color-space and higher color-depths ("deep color") are optional. HDMI permits xvYCC 4:4:4 (8–16 bits per component), YCbCr 4:4:4 (8–16 bits per component), or YCbCr 4:2:2 (8–12 bits per component).[43][44] The color spaces that can be used by HDMI are ITU-R BT.601, ITU-R BT.709-5 and IEC 61966-2-4.[43]

    For digital audio, if an HDMI device supports audio, it is required to support the baseline format: stereo (uncompressed) PCM. Other formats are optional, with HDMI allowing up to 8 channels of uncompressed audio at sample sizes of 16-bit, 20-bit and 24-bit, with sample rates of 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz and 192 kHz.[21][45] HDMI also supports any IEC 61937-compliant compressed audio stream, such as Dolby Digital and DTS, and up to 8 channels of one-bit DSD audio (used on Super Audio CDs) at rates up to four times that of Super Audio CD.[45] With version 1.3, HDMI supports lossless compressed audio streams Dolby TrueHD and DTS-HD Master Audio.[45] As with the YCbCr video, device support for audio is optional.

    The HDMI standard was not designed to include passing closed caption data (for example, subtitles) to the television for decoding.[46] 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. For example, a DVD player sending an upscaled 720p/1080i format via HDMI to an HDTV has no method to pass Closed Captioning data so that the HDTV can decode as there is no line 21 VBI in that format.

  • Re:Cat5 (Score:2, Informative)

    by Mashiki (184564) <mashiki&gmail,com> on Saturday May 14, 2011 @03:33PM (#36128686) Homepage

    What really ruins Cat5 is how good the shielding wire is. You can get good, cheap cat 5 cable. But if the shielding wire is 28-34ga while the main conductor is 24ga you get what you pay for. That also really makes a difference when they 'stretch' out the twists for shielding. Both twist, and gauge count matter in Cat5.

  • Re:Cat5 (Score:4, Informative)

    by DarthStrydre (685032) on Saturday May 14, 2011 @03:43PM (#36128742)

    You do realize that the vast majority of ethernet cables are unshielded right? And that the shielding actually decreases performance measurably?

  • Re:Cat5 (Score:5, Informative)

    by tweak13 (1171627) on Saturday May 14, 2011 @03:47PM (#36128770)
    What are you talking about? The vast majority of Cat 5 is unshielded. On the off chance it does have shielding it's usually foil. The main noise rejection strategy with twisted pair is running a balanced signal, thus the requirement for signal lines in pairs.
  • Re:Cat5 (Score:5, Informative)

    by RobertM1968 (951074) on Saturday May 14, 2011 @03:59PM (#36128858) Homepage Journal

    I used to think the same thing about Ethernet cables. it's all digital right? And yet I've seen speeds increase 10 fold when replacing old one.

    Define "old one". Are you referring to a 10/100 cable that does not support gigabit? I've seen quite a few such cables (heck, even being sold today) that only have two pairs and will not negotiate at gigabit speeds. I recently replaced a few at a client's office actually, and they were installed only 5 or so years ago.

    I've even found some that have all four pairs - but only two actually crimped into the connector (the other two pairs simply terminate in the plug, uncrimped). Again, no gigabit speeds there.

    I make my own ethernet cables from boxed wire bought at Home Depot or Lowes (Cat 5e - or occasionally Cat 6), and they all (even at various lengths, up to and including a few 100+ foot runs) perform just as well as any of the name brand, uber-expensive cables we've got lying around here. Oh - and I'm knowledgeable enough to actually check for things like retransmissions, "collisions" (ie: apparent ones due to echo/crosstalk, as switches shouldnt have such an issue), errors, etc. I can most definitely tell you, that unless you try very very hard to buy a crap cable, the results are generally within the norm regardless of price.

    Now, if you MAKE cables, that's different. (1) I've found ones poorly crimped, (2) ones where the pairs have been unwound for feet, (3) ones where they used aluminum core wires for speeds such are not rated for, (4) ones where the wire gauge is not to spec (ie: smaller than it should be), (5) ones where the insulation is stripped off the wire before it's inserted into the plug, and so on.

    But that's not a flaw in cheap cables - it's a flaw in having someone who doesn't know what they are doing making cables.

  • by BitterOak (537666) on Saturday May 14, 2011 @04:39PM (#36129152)

    ... but the delays in the cable will be governed by the laws of physics, not by the price of the cable!

    Actually, the speed of signal propagation is determined in part by the physical properties of the cable. And there are also issues of slewing and jitter, which might be less of a problem with higher quality designs. Not to mention that cheaply manufactured cables will probably sooner develop problems with connectors and so forth.

  • by Sycraft-fu (314770) on Saturday May 14, 2011 @05:02PM (#36129292)

    You can run HDMI over Cat-5 sometimes, depending on the resolution. The thing with HDMI is the bandwidth needed varies with the signal resolution. If you just want to do 1280x720@24Hz the bandwidth (in terms of digital bits) you need is very low and thus the cable bandwidth (in terms of analogue frequency) is also very low. If you want to do 1920x1080@120Hz it is much higher.

    It also depends on how noisy your environment is. Your example with power cables is a bad one since that is too low frequency to matter to HDMI. However if you have noise in the 100s of MHz, that is the range of the signal over the cable and thus interference can happen if the run is too long, or if the shield is bad (or non existent as in your case).

    So for consumers the easy guide to follow is just to check the cable's certification. Any cable worth buying will tell you if it is certified standard speed or high speed. Standard speed is a certification for 720p or 1080i, high speed is for 1080p. If you get a cable that is certified to the speed you need, you are good to go. All the cables from cheap places like Monoprice are.

    Now the certifications are overkill, as is usually the case with this stuff. You'll find that you can usually get a longer "standard speed" cable and run 1080p over it no problem. However the reason for the overkill certifications is that it'll work in more or less any conditions. The farther you go out of the spec, the more likely a problem is.

    Same deal with Ethernet. If you try it, you discover that you can indeed have cable runs over 100 meters, sometimes WAY over. Thing is, sometimes you'll have problems if you try. 100 meters is the "going to work almost no matter what" spec.

    Thus "just follow the spec" is my advice for regular users. High speed HDMI cables are cheap as hell from Monoprice and you just won't have any trouble.

  • by Sycraft-fu (314770) on Saturday May 14, 2011 @05:18PM (#36129408)

    So upsampling is basically just using a technology that is better than nearest neighbour to increase resolution. DVDs are 720x480, and a full HD LCD is 1920x1080. Obviously you have to deal with that difference. If you just stretch the pixels that works fine, but doesn't look that good. What you can do is use more advanced math to try and make the upsampling look better.

    A simple example would be bicubic interpolation. You can find that in most 2D graphics programs like Photoshop. Try taking something and playing it up with nearest neighbour, and then with bicubic. While it isn't magic, bicubic looks much better.

    For more advanced examples look at 2xSal. hq4x and the like (http://en.wikipedia.org/wiki/Pixel_art_scaling_algorithms). These ones are designed for pixel art for things like old video games, but it shows you what I'm talking about. The result is much better than things scaled with straight pixel duplication.

    In terms of the specifics for video upsampling, well it varies based on the chip used to do it, and it is all proprietary. They won't release the details. However the idea is the same. They use various algorithms to look at a frame (and sometimes data from surrounding frames) to do a more intelligent upsample.

    The result is pretty good when done well. It is amazing how good an upsampled DVD can look. Not as clear as something actually shot in HD, of course, but not bad.

  • Re:Denon Gets It (Score:5, Informative)

    by Dahamma (304068) on Saturday May 14, 2011 @05:19PM (#36129418)

    How can you even refer to that cable without the Amazon page?? ;)

    http://www.amazon.com/Denon-AKDL1-Dedicated-Link-Cable/dp/B000I1X6PM [amazon.com]

    If you haven't read the user comments, you need to...

  • Re:no (Score:4, Informative)

    by DarwinSurvivor (1752106) on Saturday May 14, 2011 @05:42PM (#36129548)
    There's another possibility. Look at the history (click on the actual score). There's a good chance they already had 2 negative mods and 2 +1 informative (thus showing 0). When you add +1 funny, they get a final score of +1 and "informative" has more votes than "funny" and so takes the lead.

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