My Journey of Discovery through HDTV Land
I recently began investigating high-definition TVs (HDTVs), as our venerable (read: 9 year-old) 53" Sony projection TV is just about to kick the bucket. Some of you may be surprised to hear that I haven't made the leap to HD by now, but the combination of high cost and lack of HD content has kept my gadget geek side at bay until now.
This blog entry is intended to help me understand (and remember) some of the lingo, technology and jargon that swirls around the world of HD--and hopefully it will be of use to you as well. I'm going to separate this into four sections: 1) HD Standards, 2) HD TVs, 3) Broadcast HD Sources, and 4) HD DVDs/Players. In order to increase readability and allow me to separate this into manageable chunks, I'll split it into two pieces: #1 and #2 will be in this post, and #3 and #4 will be published in a subsequent post.
I welcome your comments/corrections on any of this--since I'm an HD newbie, I'm bound to make mistakes. This information is my own interpretation of information that I've culled from a variety of sources: Internet, Big-Box sales personnel, friends, etc., and not all of it may be accurate.
1. HD Standards
One of the most confusing aspects of HD are the variety of video standards floating around: 720p, 1080i, and 1080p and the three most prevalent standards, and a good understanding of what these numbers mean is critical to purchasing the right set for your needs (and budget!).
In order to understand what these standards mean, it's first necessary to understand how TV resolutions are described. The number portion of the standard indicates the number of vertical lines (also known as "resolution) that comprise the video picture--720 or 1080 lines. The general rule-of-thumb is that the higher this number, the better, as the more lines of resolution there are, the closer together they are, and the finer the picture. This is especially critical as the size of the TV gets larger--especially over 46 inches or so.
By comparison, regular US TV broadcast standards (known as NTSC) have only 486 lines of resolution (sometimes referred to as '480i'), so 720p sets represent a ~148% sharper picture than conventional TVs, and 1080i/p TVs are ~222% sharper (note that these figures only consider the vertical resolution). Specifically, 720p has a resolution of 1280x720 pixels (horizonal x vertical), and 1080i/p resolution is 1920x1080. European broadcasts use the PAL standard, which has 576 lines of resolution (also referred to as 576i).
Next, let's examine the little letter after the vertical resolution number: i and p. 'i' stands for 'interlaced', and 'p' stands for 'progressive'. Interlaced, which dates back to the original NTSC and PAL standards, means that the vertical lines on the screen are painted either even or odd first, followed by the opposite--in other words, only 1/2 of the screen is painted per pass, or refresh. Progressive indicates that the TV screen is painted one line at a time, and the entire screen is painted per refresh. Progressive monitors are considered superior as they have less 'flicker' (which is a side effect of interlacing).
Based on all of this, it is safe to assume that 720p is clearly better than 480i/476i, 1080i is better than 720p, and 1080p is the best of all. Interestingly, 720p is actually much closer to 1080i than you might think--progressive scanning makes up for a lot of the flicker that comes with interlaced signals.
Unfortunately, the ability to take advantage of the various HD resolutions is a factor of the HD source's ability to actually provide that much resolution (more on that later).
2. HD TVs
There are a bewildering number of HD TV technologies on the market today. In order to prevent writing the great American novel, I'll condense them down into two main categories: flat panel and projection TVs.
Flat Panel TVs
Flat Panel TVs have several key advantages. First, they are very thin and light-generally only a few inches deep and under 100 pounds in weight, which allows them to be mounted on walls. Tube-based TVs can weigh several hundred pounds and be 18 inches deep, in comparison. Flat Panels also use less electricity and put out less heat than comparable tube TVs.
There are two main types of flat panel TVs: LCD and Plasma. Both technologies have advantages and disadvantages. Plasma TVs, which operate on the principle of exciting luminescent gas, are generally less expensive than comparably-sized LCD sets. Plasma sets feature good color and black rendition and work well for signals with a lot of movement (like sports). The main drawback of plasma sets are that they are prone to "burn in" (if the set is left with the same image displayed for too long, the image may be permanently "ghosted" on the screen), and plasma sets are also reported to have lower life spans when installed at high altitudes (generally over 6,000 feet). There are a new crop of plasma TVs that are rated to work up to 9,000 feet; if you live at one of these altitudes, it would be best to make sure you buy a high-altitude rated plasma or an LCD panel. Also note that the noble gases used with plasma sets gradually fade over time, and plasma sets also require a "backlight" that must be replaced over time.
LCD panels rely upon millions of discrete LCDs to comprise the video picture--virtually the same technology that computer flat screens use, only much larger. Advantages of LCDs include long life, low power consumption, no burn-in problems, and high-altitude compatibility. Disadvantages include less vibrant color than plasma and the tendency for high-speed images to leave a trail (the reaction time of LCDs are typically much slower than plasma). A new crop of "120 Hz" LCD TVs is reported to help solve many of the speed problems, but at a premium. LCD TVs are also generally more expensive than comparable plasma sets, although the gap is narrowing. LCDs also require "backlights", which need to be replaced over time (generally every 9,000 to 12,000 hours).
Rear Projection TVs
I recently began investigating high-definition TVs (HDTVs), as our venerable (read: 9 year-old) 53" Sony projection TV is just about to kick the bucket. Some of you may be surprised to hear that I haven't made the leap to HD by now, but the combination of high cost and lack of HD content has kept my gadget geek side at bay until now.
This blog entry is intended to help me understand (and remember) some of the lingo, technology and jargon that swirls around the world of HD--and hopefully it will be of use to you as well. I'm going to separate this into four sections: 1) HD Standards, 2) HD TVs, 3) Broadcast HD Sources, and 4) HD DVDs/Players. In order to increase readability and allow me to separate this into manageable chunks, I'll split it into two pieces: #1 and #2 will be in this post, and #3 and #4 will be published in a subsequent post.
I welcome your comments/corrections on any of this--since I'm an HD newbie, I'm bound to make mistakes. This information is my own interpretation of information that I've culled from a variety of sources: Internet, Big-Box sales personnel, friends, etc., and not all of it may be accurate.
1. HD Standards
One of the most confusing aspects of HD are the variety of video standards floating around: 720p, 1080i, and 1080p and the three most prevalent standards, and a good understanding of what these numbers mean is critical to purchasing the right set for your needs (and budget!).
In order to understand what these standards mean, it's first necessary to understand how TV resolutions are described. The number portion of the standard indicates the number of vertical lines (also known as "resolution) that comprise the video picture--720 or 1080 lines. The general rule-of-thumb is that the higher this number, the better, as the more lines of resolution there are, the closer together they are, and the finer the picture. This is especially critical as the size of the TV gets larger--especially over 46 inches or so.
By comparison, regular US TV broadcast standards (known as NTSC) have only 486 lines of resolution (sometimes referred to as '480i'), so 720p sets represent a ~148% sharper picture than conventional TVs, and 1080i/p TVs are ~222% sharper (note that these figures only consider the vertical resolution). Specifically, 720p has a resolution of 1280x720 pixels (horizonal x vertical), and 1080i/p resolution is 1920x1080. European broadcasts use the PAL standard, which has 576 lines of resolution (also referred to as 576i).
Next, let's examine the little letter after the vertical resolution number: i and p. 'i' stands for 'interlaced', and 'p' stands for 'progressive'. Interlaced, which dates back to the original NTSC and PAL standards, means that the vertical lines on the screen are painted either even or odd first, followed by the opposite--in other words, only 1/2 of the screen is painted per pass, or refresh. Progressive indicates that the TV screen is painted one line at a time, and the entire screen is painted per refresh. Progressive monitors are considered superior as they have less 'flicker' (which is a side effect of interlacing).
Based on all of this, it is safe to assume that 720p is clearly better than 480i/476i, 1080i is better than 720p, and 1080p is the best of all. Interestingly, 720p is actually much closer to 1080i than you might think--progressive scanning makes up for a lot of the flicker that comes with interlaced signals.
Unfortunately, the ability to take advantage of the various HD resolutions is a factor of the HD source's ability to actually provide that much resolution (more on that later).
2. HD TVs
There are a bewildering number of HD TV technologies on the market today. In order to prevent writing the great American novel, I'll condense them down into two main categories: flat panel and projection TVs.
Flat Panel TVs
Flat Panel TVs have several key advantages. First, they are very thin and light-generally only a few inches deep and under 100 pounds in weight, which allows them to be mounted on walls. Tube-based TVs can weigh several hundred pounds and be 18 inches deep, in comparison. Flat Panels also use less electricity and put out less heat than comparable tube TVs.
There are two main types of flat panel TVs: LCD and Plasma. Both technologies have advantages and disadvantages. Plasma TVs, which operate on the principle of exciting luminescent gas, are generally less expensive than comparably-sized LCD sets. Plasma sets feature good color and black rendition and work well for signals with a lot of movement (like sports). The main drawback of plasma sets are that they are prone to "burn in" (if the set is left with the same image displayed for too long, the image may be permanently "ghosted" on the screen), and plasma sets are also reported to have lower life spans when installed at high altitudes (generally over 6,000 feet). There are a new crop of plasma TVs that are rated to work up to 9,000 feet; if you live at one of these altitudes, it would be best to make sure you buy a high-altitude rated plasma or an LCD panel. Also note that the noble gases used with plasma sets gradually fade over time, and plasma sets also require a "backlight" that must be replaced over time.
LCD panels rely upon millions of discrete LCDs to comprise the video picture--virtually the same technology that computer flat screens use, only much larger. Advantages of LCDs include long life, low power consumption, no burn-in problems, and high-altitude compatibility. Disadvantages include less vibrant color than plasma and the tendency for high-speed images to leave a trail (the reaction time of LCDs are typically much slower than plasma). A new crop of "120 Hz" LCD TVs is reported to help solve many of the speed problems, but at a premium. LCD TVs are also generally more expensive than comparable plasma sets, although the gap is narrowing. LCDs also require "backlights", which need to be replaced over time (generally every 9,000 to 12,000 hours).
Rear Projection TVs
There are a mind-numbing number of different rear projection HD TVs. Projection TVs are generally much less expensive than flat panel TVs, and they are also deeper (only some projection TVs are thin enough to be wall mounted). Many projection TVs also have a much narrower range of viewing angles than flat panels (in other words, they become dim as one moves to the extreme left or right side of the TV).
The best known HD projection technology, Digital Light Processing (DLP) relies on millions of microscopically tiny mirrors that are laid out on a semiconductor chip. Light is reflected from the mirrors on to the screen, and each mirror corresponds to a pixel on the screen. Advantages of DLP include low cost, good color and movement rendering, no possibility of burn-in, and an easily replaceable light source. Disadvantages include poor viewing angle, possible eye strain (reported by some users), fan noise (in some units), and much thicker cabinets than flat panels.
Other HD projection technologies on the market include LCoS (Liquid Crystal on Silicon) and LCD projection. I have not done much research on the non-DLP projection sets to date, although DLP repoertedly has the thinnest cabinets of the three projection technologies.
Coming Soon
As mentioned at the top of this entry, I will be publishing the second half of this posting shortly, which will cover various live HD content sources as well as the options for DVD sources.
