> All this HD stuff has me majorly confused. But I know crunch time is > coming in about 18 months or so regarding mandated broadcasting in HD. > Maybe then I'll have a better understanding. Hopefully, this Tivo > will last a bit longer before I have to replace it.
So in my last email I talked about crunch time in Feb 09, and what it really means to us (summary: not that much). But let's suppose you're interested in taking advantage of HDTV anyway. Where do you start? There's a lot of information out there and, worse yet, a lot of misinformation. (Sometimes I wander through Best Buy and here the most outrageous things said to people. I feel like interrupting the sales kid and telling the customers the truth, but experience has taught me that that just gets me kicked out, or at least earns me some very odd looks.) As I mentioned in my last email, there is a difference between digital TV (DTV) and high definition TV (HDTV). DTV just means a digital broadcast, whereas HDTV tends to mean a high resolution broadcast. (I'll get to numbers in a sec.) As I also mentioned, nearly everybody gets their TV from one or more of the following sources: cable, satellite, or over-the-air via antenna (OTA). Now the first question many people ask is, "Why should I?" The answer is, "Go see it in action." Go see some HDTV, and you'll know. I can give you numbers and stats and describe it until I'm blue in the face, but none of that will convince you. If you see it in action, however, you'll be sold. Even if you have to see it at a big box store with horrible lighting and the TVs set to the worst possible settings. Go right now. I'll wait for you to get back. OK. Convinced now? So let's talk about where you can get HDTV programming first, and then we'll talk about TVs and resolutions and all that nonsense. Satellite: both Dish and DirecTV offer a variety of HDTV channels. Dish currently has more, although a lot of them are the old VOOM channels that, on the whole, strike me as a waste of time. But one person's waste of time is another person's weekend of bliss, so don't go by me. Unfortunately, neither offer a Tivo-based solution. :( You can still get the only Tivo-based HD satellite DVR (the HR10-250) on eBay, but it won't work with the satellite-based HD locals that DirecTV now offers, and it won't work with the new channels DirecTV is adding in a couple of months. On the other hand, it works with both satellite *and* DTV OTA broadcasts, so if you have decent reception for OTA signals, you can at least get that. Cable: depending on where you live, your cable provider may offer a nice selection of HD channels. As an added bonus, you can use a Series 3 Tivo with cable, using devices known as "CableCards." CableCards are little cards you get from your cable company that slide into slots on the S3 Tivo and allow it to tune encrypted cable channels without a cable box. OTA: depending on where you live, stations may be broadcasting HD signals that you can pick up with an antenna for free. If you're pretty rural, then you may be out of luck, but if you live in a city or suburban area, there might be oodles and boodles of stations. You can also find "subchannels" which, I think, require a bit of explanation by way of example. My local ABC station is on channel 7 (analog). OTA DTV broadcasts use decimals to represent themselves, so the OTA DTV channel for my ABC station is 7.1 (or 7-1 on some receivers). But there is also 7.2, which has reruns of the local news, and 7.3, which has 24 hour weather. Cable systems and satellite systems only carry the main 7.1 feed. A lot of the time the subchannels are fluff -- the weather feed being a prime example. After all, in addition to the weather channel on cable/sat, there's also weather.com. :) But sometimes they've got good stuff. In my market, WGN (9 analog, 9.1 DTV) has a 24-hour music video network called "The Tube" on 9.2 that has a pretty good variety of music. And I don't know if this is still the case, but as of a couple of years ago, the Fox affiliate in Champaign-Urbana used their ".2" subchannel for NFL broadcasts WITHOUT announcers -- just ambient stadium noise. Seriously, I'd pay a fee for that. :) OK, so there's definitely programming out there. What do you need, TV-wise? I'm not going to get into plasma versus LCD versus DLP versus...etc. Everyone has a budget and everyone has personal preferences. Go look at the sets and see what you like. If possible, make the store give you the remote so you can adjust the settings -- most TVs in the store are left at the default settings, which are often referred to as "torch mode" because the brightness, contrast, etc. are cranked up to the max. It's just awful. What I will say is that I would insist on a minimum of two HDMI ports. HDMI is a way of connecting external boxes (cable/sat box, HD-DVD or Blu-Ray player, etc.) for HD video and audio. But more importantly, they allow for a copy-protected connection that some things insist on. (If you want the best resolution out of HD-DVD or Blu-Ray, I think you need HDMI. Actually it's not HDMI itself so much as the copy-protection protocol HDCP, but that only really matters to us nerds.) Cable and satellite boxes don't seem to require HDMI w/HDCP yet -- they can also use component video connections -- but other devices do and more of them will. (Heck, I got an upscaling DVD player that requires it, for no adequately-explored reason.) The other thing to consider is the resolution of the TV, and for this part I need to issue a WARNING ** WARNING ** WARNING ** WARNING TECHNOBABBLE TO FOLLOW! I hate to do this, because an awful lot of this is just gobbledygook, but this is where so much misinformation lives. I'll try and keep the technobabble to a minimum. If this isn't clear, let me know. TV broadcasts: the old-fashion type Here in the US, the TV system that we all grew up with is referred to as NTSC. NTSC broadcasts have 480 "lines of resolution" and 60 interlaced fields per second. "In English," I hear you say. OK. Um...well the 480 lines is the resolution of the image. There are 480 lines of video, stacked on top of each other. Except...not all at once. NTSC uses something called "interlacing" as a technique to fit more "video information" into the picture. Without interlacing, the original TV might have only been half as high! In any case, what you really see is the odd-numbered lines, followed by the even-numbered lines, over and over. This happens 60 times per second. Each group of lines (240 odd lines or 240 even lines) is called a "field" and so you get 60 fields per second. (This was done because our electrical system runs at 60Hz, so it made the timing easy. I'm oversimplifying but that's essentially it.) Whew. I hope that made some kind of sense. If it did...good, because that's going to make the rest of this a cake walk. What complicated this was film. Not only movies; nearly all TV dramas and even sitcoms are shot on film. Film resolution is...well, it's real high. Higher than HDTV. :) But film is 24 progressive frames of video per second. What does that mean? "Progressive frames" just means that there's no interlacing going on; each "frame" has the entire picture instead of just odd lines or just even lines. So if something was shot on film, and it needs to be broadcast on TV, it has to be converted from 24 progressive frames per second to 60 interlaced fields per second. How do they do this? Well, for every second ov video, they first add 6 "duplicate" frames (they repeat a few) to get 30 frames of video per second. Then they interlace them, or split them into odd-and-even fields, which gets you 60 fields per second. Another "whew." Why this is important comes up shortly, I promise. TV broadcasts: the new age The new broadcast standard is called "ATSC" and, unlike the old-fashioned kind, has MULTIPLE resolutions and frame rates. The most common: 480p: 480 lines, just like the good old days, BUT 60 progressive frames/sec 720p: 720 lines, with 60 progressive frames/sec 1080i: 1080 lines, with 60 interlaced fields/sec Note that only the 720p and 1080i formats are really considered "HDTV" resolutions. Just like with old-fashioned TV, if the movie or TV show was shot on film, it has to be converted into 60 interlaced fields per second (in the case of 1080i) or 60 progressive frames per second (using a similar process, in the case of 480p or 720p). Most HDTVs are "fixed pixel" displays. In other words, they are set to a specific resolution. If you feed them anything else, they scale it to their own resolution. For example, one of my TVs is an LCD with a 720p resolution (actually it's 768, but it's close enough for government work). If I watch something broadcast in 1080i, the TV shrinks it down. If I watch something in 480i or 480p, it blows it up. This is done by some electronics in the TV, collectively referred to as a scaler. CBS and NBC broadcast in 1080i, along with most of the cable/sat networks (HBO, Showtime, HDNet, HDNet Movies, TNT, UniversalHD, and so on). ABC, Fox, and the ESPN networks are 720p. Also, most (but not all) HDTVs are "progressive" displays. They're designed to show all lines at once. If you feed it something interlaced (like 1080i), it's going to have to convert it to a progressive format. It may just put the two interlaced fields together, converting 60 interlaced fields into 30 progressive frames. But something else modern TVs try to do, if they're clever enough: they try to "restore" film-sourced material to the original 24 progressive frames/sec. In other words...the scaler tries to look at the video and figure out if the interlacing process was used to add extra frames and split them up. If so...it tries to un-do all that, so that ultimately what you see is the original 24 progressive frames. OK, so why did I waste all those words on that techy nonsense? Because I'm going to recommend that, if you can manage it within your budget, you go for a TV that can display 1080p. One of the things that I often hear said about 1080p is, "Well, why should I bother? Nothing is broadcast in 1080p!" This is bogus reasoning. If you're watching something that was interlaced in the first place, your progressive display is just going to convert interlaced into progressive anyway, and if it was originally shot on film, it's going to try and restore the original progressive material. And since most channels are 1080i at this point...a TV that can do a 1080 resolution makes the most sense. So there you go. Sorry for that bewildering array of crap. Bottom line: find a TV that looks good to you, and if you can afford it, get one that can do 1080p. Even if you don't...prepare to be blown away, because HDTV looks incredible. -- Christopher D. Heer -- [EMAIL PROTECTED]
