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<p>My pleasure.</p>
<p>CRT: cathode ray-tube, the semi-original tv technology (there was actually a non-electrical version invented first, we’ll ignore it). The tvs you watched growing up were CRT. Contrary to popular belief, CRTs can have flat screens (though not flat <em>panel</em> screens, i.e. the thin kind), and until the mid-noughts they were still the most common technology for big-screen HDTVs. Weirdly, there were even some 4:3 (non-widescreen) HDTVs made using CRT technology. The big rear-projection sets that dominated the market until LCD and PDP became “affordable” used three seven-inch screens bounced off a mirror onto the screen, using electromagnets to keep the picture aligned (this is called convergence and is like changing oil on a car, it’s something that has to be done with these sets every so often). Because of how awesome a properly-maintained CRT HDTV can be, many high-end home theaters still use them. Sony sold a projection system for high-end home theater that you’d be lucky to get for $20,000.</p>
<p>HDTV: There’s a lot to say about it, but to sum it up really quickly, back in the 1960s the Japanese decided to make a tv with a large screen that could replace the movie theater. Their research showed that it would need about a thousand lines of resolution. This is why I do not consider 720p to be true HD, regardless of what electronics manufacturers say. It falls shorts of the original “dream.” It’s like saying you are in outer space when you’re technically still in the upper atmosphere. Japan has had HDTV broadcasts since the late 1980s, and high-definition laserdisc movies since the 1990s. We thought Blu-Ray was the bees knees, but they had the option of watching Lawrence of Arabia or Jurassic Park in HDTV in their homes when we were starting to use the web and choosing between Clinton and Dole. It was an analog system though. Now everybody uses a digital system. The two main flavors of HDTV are: </p>
<p>720p: 1280 pixels across by 720 pixels vertically. Each frame is drawn in a single pass. Without understanding how old-style CRTs work this doesn’t seem all that significant. Suffice it to say, progressive scan images (the ‘p’ in 720p) are smoother and free from jitter, unlike interlaced images. Most “HDTVs” sold in the last six years or so are probably native 720p, they cannot display the full detail of 1080i/p, it must be down-converted.</p>
<p>1080i/p: Twice the pixels of 720p, it features 1920 pixels across and 1080 pixels vertically. 1080i means every other row of pixels is drawn first (completing what’s called a field), then the remaining rows of pixels between the first ones are drawn next (completing the whole frame). That’s what interlacing means. Only really distracting during camera pans, and with film-based, twenty-four-frames-per-second source material, you’re going to get some jitter anyway. 1080p means the image is progressive, the whole frame is drawn at once. All CRT HDTVs (with one exception) can only do either 1080i or 1080p, any 720p image must be converted. In fact, some high-end CRT front-projection systems (ceiling mounted) can do 2500p or higher.</p>
<p>RPTV: Rear-projection tv. A tv using some kind of projection system built into one big cabinet. As opposed to FPTV, ceiling or floor mounted projection systems (the really good ones that rich people have in custom home theaters).</p>
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