HDTV: 1080p vs. 1080i vs. ?

Discussion in 'Buying Tips and Advice' started by munckee, Dec 28, 2006.

  1. munckee macrumors 65816

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    #1
    I'm looking to purchase a new TV in the next month or so and I'm trying to decifer all the jargon about HDTV, etc. I'll be looking for a 40-42" LCD that's HD ready.

    Can anyone help me understand the advantages of 1080p vs. 1080i vs. all the other stuff they're using to sell these things?

    Thanks!
     
  2. balamw Moderator

    balamw

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    #2
    What HD devices and services are you planning to hook up to this TV?

    It'll help figure that out.

    B
     
  3. mkrishnan Moderator emeritus

    mkrishnan

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    #3
    At least a basic terminology primer may be useful... but probably also available elsewhere! :eek: ;) :D

    You might start with this one:

    http://www.cnet.com/4520-7874_1-5108580-3.html

    The C|Net people have many well deserved pejorative reputations... ;) But I think that they do this sort of thing well.
     
  4. munckee thread starter macrumors 65816

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    #4
    Don't know at this point. It's actually my mom who's looking, but I didn't see the point in explaining all that (until now). So, realistically, it'll get hooked up to a standard DVD player (until HD becomes the norm down the road, if the TV is still kicking of course) and cable with DVR. She may decide to spring for HD cable as well since she'll have the TV for it.

    She's not looking for the best of the best, but would prefer to buy a TV that will be future-proofed for a little while rather than needing to replace it sooner.
     
  5. balamw Moderator

    balamw

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  6. wasimyaqoob macrumors 6502a

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    #6
    When I bought my LG TV, it said 'HD Ready' but it doesnt even have a HDMI Port, only has a DVI Port - Will there be any loss in HD Quality and is it really High-Definition?
     
  7. munckee thread starter macrumors 65816

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    #7
    Thanks, that was helpful. I guess the question now is what's actually being broadcast. It appears that, at least for the time being, 1080p is overkill. So can any 1080i set also display 720p, or do I have to choose between the two?

    How far off are we from needing 1080p sets? Is it worth buying now not to have to buy again later?
     
  8. balamw Moderator

    balamw

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    #8
    HDMI is pin compatible with DVI and just adds in digital audio. As long as your DVI port is HDCP compatible there's no real difference.

    B
     
  9. mkrishnan Moderator emeritus

    mkrishnan

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    #9
    "HD Ready" has typically meant that the TV doesn't have an ATSC tuner and so cannot actually tune over-the-air HD content (although most TVs at this point should have them, I think that there are still some left-overs).

    As far as HDMI...this is something that has been gone over many times but is confusing.

    HDMI and DVI carry the same digital signal. Meaning that generally, the video quality is the same. There are very cheap cable adapters that go from DVI to HDMI (because that is easy, unlike going from component to HDMI, which is very difficult). There are however, some important distinctions:

    1) Not all DVI ports, even today, to my knowledge, support HDCP (copy protection), although the number that do is rapidly increasing. All HDMI ports today are supposed to support HDCP, but some HDMI ports in the past did not.

    2) HDMI bundles audio, whereas DVI is video only.

    So the only time the HDMI video quality would be better than DVI is if you had an HDMI port that did HDCP and your DVI port did not, and you had a device that required HDCP to output at full quality (e.g. a Blu-Ray player).
     
  10. balamw Moderator

    balamw

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    #10
    Anything that calls itself a HDTV MUST downconvert 1080i to 720p.

    1080p will only be an issue if you're planning a HD-DVD/BluRay player or maybe Xbox/PS3.

    B
     
  11. mkrishnan Moderator emeritus

    mkrishnan

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    #11
    Mmm, not quite?

    I think that anything that calls itself an HDTV must either "down" convert to 720p (which is actually a better picture generally, from what I've heard, than 1080i) or upconvert to 1080p. The latter is what the best TVs would do -- they'd scan double the 1080i to 1080p.

    At this point, it does seem that 1080p is several years off being a necessity. It all depends on what you want to do. But I don't think much of anything is going to "require" you to have 1080p for many, many years, since the HDTV standard does not require you to have 1080p.

    It's amazing how murky this is. Is it any less murky in countries that were not as slow to go HD as we were?
     
  12. -hh macrumors 68020

    -hh

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    #12
    The FCC has been requiring manufacturers to include ATSC tuners in their TV's, and it has been phasing in based on screen size - - the biggest stuff first.

    In KISS terms, this means:

    small TV set: NTSC tuner, with ATSC tuner optional
    big TV set: NTSC tuner and the ATSC tuner is mandatory.

    I forget what screen size is part of the mandate today, but I believe that its down to 27" (and larger) TV sets right now.

    However, there was a loophole in this regulation that some manufacturers exploited: the FCC-mandated ATSC tuner need only be present if the set included an NTSC tuner.

    As a result, some models aren't "TV's" anymore because they have NO tuner whatsoever. These are typically referred to as "(HDTV ready) Monitors", and you'll need to figure out how to get the signal into them. Which means we have to add a third line to the above:

    small TV set: NTSC tuner included; ATSC tuner optional
    a big TV set: NTSC tuner and ATSC tuner included
    Any Monitor: No NTSC tuner, No ATSC tuner


    If you're on Cable TV, getting a monitor shouldn't be a big deal, as you'll probably be using a cable box. However, having no ATSC tuner means that you won't be able to find out if you can grab the free HD Over-the-Air (OTA) signal (needs a UHF antenna - cheap), which may allow you to drop cable TV and its accompanying monthly bill

    YMMV, but I'm going to try for the free OTA ATSC signal, as this would let me pocket roughly $50 per month.


    -hh
     
  13. mkrishnan Moderator emeritus

    mkrishnan

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    #14
    The C|Net article also said that the cut line was at 25" (so TVs larger than this must have ATSC). But as far as I know, this doesn't prevent liquidation of old stock... and I think that's where the problem comes in. If you get a Best Buy item on sale, fine. But if you shop at TigerDirect, or even less egregious online sources, you have to be very careful about this.

    But, so this is the thing that I wonder about... I have no ATSC antenna. And I don't know anyone who does, either. How good is the quality, typically? It seemed like, except for people lucky enough to have the bigger roof antennas held over from the 70s, NTSC was never very good at all over the air....
     
  14. mkrishnan Moderator emeritus

    mkrishnan

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    #15
    flopticalcube, according to that chart... at my viewing distance (12'), I would need to have a 65" television to need 1080p... Which would feel a lot like sitting way in front in the movie theater... which I don't particularly want.

    So it would rather seem to make the case against needing 1080p than for it. :D
     
  15. jtown macrumors 6502

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    #16
    It's not really murky. The specs are clearly spelled out. And "balamw" is just plain wrong.

    There are currently two types of HD being broadcast in the US. 720p and 1080i. (Some cable companies try to sneak 480p into their HD lineup but it doesn't count in my opinion.)

    If you're buying an LCD panel, they have fixed resolutions. They'll either be 1366x768 or 1920x1080. (Okay, there are some 1280x768 displays out there, too.) If you get a 1366x768 display, it will show 720p programming in its native resolution and will scale 1080i programming down to 720 lines and 480i/p up to 720 lines. If you get a 1920x1080 display, it will show 1080i programming in its native resolution and scale 720p programming up to 1080 lines and 480i/p up to 1080 lines.

    Which is best? Depends on what you want to watch. Your cable/satellite company can tell you which resolution is used by each channel. If you're buying the set mostly to watch sports and the sports channels are broadcast at 720p, then it makes sense to buy a 1366x768 display because you will see the truest representation of the original source material. If the channels you will watch the most are broadcasting 1080i, get a 1920x1080 display. If you're going to hook it up to a computer, Xbox, PS3, etc. get a 1920x1080 display and make sure it can accept true 1080p input.

    If you get a CRT, you can think of it like any old multi-sync monitor you've owned in the last 15 years. They adapt well to multiple resolutions due to the way CRTs work. They don't have a "native" resolution. IMHO, this makes them a better choice if your viewing will be purely HDTV with no computer or game console hookup. However, HD CRTs top out around 34". And I haven't seen any HD CRTs that can display 1080p (which is odd considering I used to run higher resolutions computer monitors).

    As for HDMI/DVI, think of HDMI as DVI+. It carries the exact same video signal as DVI as well as audio. DVI doesn't carry audio. There are also some new features coming out in the next HDMI spec but it will still be able to take input from DVI sources. You can buy DVI->HDMI and HDMI->DVI cables for ten bucks online. They just change the connectors. There's no circuitry in there. And no reason to go spending $100 at Best Buy. It's a digital signal. It'll either work or it won't.

    BTW, at this point, future-proofing your HD display means making sure you have plenty of inputs. My new TV has 6 HD inputs and, between the tivo, upscaling dvd player, two computers, and PS2 (plugged into component even tho it's not HD), I only have one left.
     
  16. mr_matalino macrumors 6502a

    mr_matalino

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    #17
    Huh. I didn't know about the HDCP...thanks for the info (although I had to read the post about 5x before I understood) :eek:
     
  17. balamw Moderator

    balamw

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    #18
    You're right I was going to correct it, but had to step away.

    It's been known to happen. :p

    What I meant to say is that any HDTV must accept both 720p and 1080i and display them to the best of its abilities, but is not required to do anything with 1080p.

    I agree fully with the inputs. Get as many as you can preferably with HDCP, just in case it ever takes off.

    B
     
  18. jtown macrumors 6502

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    #19
    I wouldn't get too hung up on the internal tuner issue. Honestly, why do you have cable/satellite now if you'd be happy with what's available OTA? Switching from cable to OTA would mean going from several dozen channels to, at most, a dozen.
     
  19. -hh macrumors 68020

    -hh

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    #20
    You're assuming that I had a real choice in the matter.

    The problem is that in a lot of newer suburban housing developments, there are a ton of deed restrictions. One typical deed restriction is what color you're allowed (or not allowed) to paint your house or front door. The deed restriction that applies here is a prohibition from installing any "large, unsightly" antennas on your house, which is specifically targeted to eliminate the traditional VHF antenna on your roof.

    VHF reception from an antenna hidden inside the attic is a snowstorm at best, which effectively means no choice but to pay for cable (or Sat). Considering how little TV we watch, this is a $600/year irritation.

    When Sat TV came into being a few years ago, one of the strategic moves that they did politically to position themselves was to get a Federal regulation that nullifies these sorts of local deed restrictions. Naturally, they did it for only "small, unobtrusive dishes", not for 'old fashioned' VHF, since this move was intended to be self-serving. But its good enough for me to use it to get OTA ATSC.

    So I'm now able to put up a dish-style UHF antenna (wineguard S-1000 or S-2000 flat panel) and grab the OTA ATSC signal for free, and get rid of my CATV monthly bill.

    Will I have fewer channels? Sure, but it saves me $50 per month for what I'm underutilizing, and the quality of what I do watch will be improved.

    A better picture at a lower price. Hard to beat that.


    -hh
     
  20. flopticalcube macrumors G4

    flopticalcube

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    #21
    Indeed. I sit at about 10 to 12 feet and with my less than perfect eyesight, 480p on a 42" plasma does me just fine (better with SD programming as well). You will have to be your own judge on this one. Remember that resolution is not nearly as important as contrast ratio or colour saturation. Look particularly at black levels. This is where plasma shines.
     
  21. swingerofbirch macrumors 68030

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    #22

    I am not debating what you are saying, but want to make sure I understand. When you say that 1080i scales down to 720, does that mean it takes some of each 1/60th of a second's lines and combine them in 1/30th of a second? Because as I understand it 1080i shows 540 lines every 1/60th of a second, and 720p shows 720 lines every 1/30th of a second.

    So my assumption would be that this conversion process takes, 2/3 of the lines from a 1080i broadcast and combines them with 2/3 of the lines from the next 1/60th second, into a "progressive" 1/30th of a second?
     
  22. jtown macrumors 6502

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    #23
    HH, try an amplified indoor antenna. You can get them for $20-40. Some people have reported great success with them (including OTA HD). Of course, that still leaves you with a comparatively small number of choices compared to cable or satellite but simply living among jack-booted HOA thugs doesn't rule it out.

    Worst case, it doesn't work and you take it back.
     
  23. wasimyaqoob macrumors 6502a

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    #24
    Well my TV can with a HD Ready sign, so im assuming its ready for HD just doesnt have a HDMI Slot!
     
  24. -hh macrumors 68020

    -hh

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    #25
    Agreed. I don't recall exactly how the FCC regulations are worded - - if its 'cessation of manufacture' or 'cessation of retail sales'. Main thing is to simply be aware of it during this transition period.


    Actually, if you have a standard VHF/UHF antenna to receive NTSC, you already have an "ATSC Antenna".

    The designation of ATSC merely identifies the signal protocol. It does not directly designate the frequency being used: ATSC uses (mostly) UHF, which we know as the old NTSC channels 14-81.

    This means that if you can get UHF channels today on NTSC, you can almost certainly get digital ATSC channels from the same antenna and wiring.

    You can check here to see what channels are available to you now, and how big of a directional antenna you need, such as one of these. In my case, I'm looking at the $100 wineguard SS-2000, which is a dish "look alike" and which means that going to OTA will will pay for itself in 2 months.


    Typically, if you get a reasonable NTSC signal, you'll get a crystal-clear ATSC digital signal, which means that your picture will be as clear as current cable TV, and because it will be HD instead of NTSC, the OTA signal will actually be sharper.


    Those 'big' VHF/UHF antennas have never gone away - - although they've been "legislated" away by housing development deed restrictions. A large one with 20 dB of gain typically retails for just under $200 and will need to be replaced every 5-10 years, depending on how harsh your local weather is.

    Needless to say, the Cable TV operators are not prone to volunteering that OTA ATSC is a viable competitor to them, at the hard-to-beat price of "free". One thing you may have also noticed is that stand-alone OTA ATSC tuner boxes for existing NTSC TV sets are rare, and at $200 and up, relatively expensive.


    -hh
     

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