A recent survey by the Leichtman Research Group, as reported in The Wall Street Journal, concluded that there are over 24 million households with High Definition TV (HDTV) sets in the US. Half of them don’t watch HD-quality programs because they don’t have the necessary hardware. But what is even more significant is that a quarter of them (6 million) erroneously think that they are watching HD-quality programs when they aren’t. The results just show how much more needs to be done to educate consumers on HD programs and HDTV.
What is HDTV?
So what exactly is HDTV? HDTV is the next-generation of TV programs that offer significantly better video quality as well as enhanced surround sound. It’s like having a near cinematic experience right in your living room. It’s so much better that even DVD-quality movies will pale in comparison. Watching the World Cup 2006 in HD meant you could even watch the beads of perspiration on the players’ faces. HD programs also run in the wide-screen 16:9 aspect ratio (compared to the standard 4:3 aspect ratio of traditional TV) which means you can watch more of the soccer field and therefore more of the action.
The secret is in the pixels and lines
When you are shooting digital pictures, the more pixels you can squeeze into your picture, the sharper and clearer your image will be. That’s why an eight Megapixel camera will be able to shoot better pictures as compared to say a three Megapixel camera. Similarly when you run a PC game at a higher resolution, say at 800 x 600 pixels as compared to 640 x 480, the better your in- game graphics will appear. The first number corresponds to the number of pixels you can display vertically and the second refers to the horizontal pixels. The same concept works on TV.
Our PAL and NTSC analogue TVs currently display 576 horizontal lines and 480 lines of pixels respectively, but this is running on interlaced mode. Interlaced means that the odd numbered lines are displayed followed by the even number lines in split seconds. To the human eye the switch is so fast that it is unable to see the time-gap and will instead see the interlaced image as one complete picture. But interlaced mode results in substantially weaker video quality, because effectively only half of the pixels are displayed at any one time. The opposite of interlaced is progressive mode, where the entire image (both the odd and even numbered lines) is displayed at the same time. The significant improvement in video quality can easily be experienced when viewing standard DVD movies, which has as many lines as analogue NTSC TV (480 lines) but displays the video in progressive as compared to interlaced mode.
HDTV comes in three main formats – 720p, 1080i and 1080p, where p and i refers to progressive and interlaced respectively. The increased number of pixels and lines lead to a significant improvement in video quality. To successfully view a HD-quality program however is not as simple as it seems. There are several factors that must be satisfied before you can enjoy HD- programs on your HDTV in its full glory in your living room.
What you need to enjoy HD-programs
There are three main factors that need to be satisfied for you to successfully watch a HD program at its full potential. The first criterion is that your local broadcaster must first be broadcasting the TV program in HD-quality. In Singapore for example, cable TV provider StarHub is screening its National Geographic and Discovery HD channels in 1080i mode at channels 301 and 302 respectively. At the same time, it is also showing the SD version of both channels at 10 and 11 respectively.
The second pre-requisite is that you must be able to receive the HD-quality programs at home. Usually, this means you will need to purchase an additional set-top box from your cable TV provider. In some cases, your HDTV could come with an in-built receiver that can receive the HD-quality programs directly without the need for equipped an additional set-top box. The third and most important factor is that you must have a TV that can successfully display the HD-programs in HD-quality. This is where consumers must make sure that they are correctly investing their money into their new HDTV set, to make sure that it can display the HD-programs for maximum effect.
So if you own an analogue TV set, whether you are tuned to channel 301 or 10, you will see the same SD quality program since your TV cannot display the HD-quality channel. One common misconception among consumers is that when they see the word “HD-channel” or “broadcasting in HD-quality” on their TV screen, they think they are watching an HD-program in HD-quality. Yes, they are watching a HD-program that is being broadcasted in HD-quality, but if they are using the analogue TV, their TV cannot output the full HD-quality and will downscale the video to SD-quality. Conversely, if you do own an HDTV set, you would be able to see the clear difference in video quality between the SD and the HD channels.
What to look out for when buying an HDTV
Firstly, you need to get an HDTV set which is able to support at least 720p. This is the minimum resolution, there is also 1080i and 1080p. These numbers refer to the number of horizontal lines that your TV can support. Now, for the mainstream LCD TVs today, the resolution is 1336 x 768, which means it can support 1280 x 720, and therefore will have no problem in displaying 720p video in its original broadcast quality. However, if the video broadcast source is in 1080i or 1080p, the TV has to downscale the image to fit into the lower screen resolution. This can result in some degradation of quality, especially when you are purchasing a larger- sized screen.
The better bet would therefore be to go for an HDTV that can support 1920 x 1080, which can display 720p, 1080i and 1080p video in its intended broadcast quality. Some HDTVs, especially plasma TVs with a smaller screen size, can only display 1084 x 1084 resolution. While this technically means that the TV meets the basic criteria (that the horizontal pixels must be at least 720) to be classified as an HDTV, the smaller number of vertical pixels (1084 vs 1920) means that there is significant downscaling of the vertical pixels and this can result in even greater video quality degradation.
This means that both the 1920 x 1080 and the 1084 x 1084 will be marketed as meeting the 1080i standard but in reality the video quality can be significantly different. Therefore, it is always imperative to check on the actual resolution of the HDTV when making a purchase. Of course getting a higher resolution will mean paying more.
The second criterion is to look at the ports at the back of the TV. In current analogue TVs, we are making use of the standard composite (red, white and yellow) cables as well as component cables (red, blue and green for video plus red and white for audio). For HDTV however, a new cable called the HDMI is used. This cable combines the high-definition video with 5.1 channel surround sound into a significantly smaller connector that plugs into the HDMI port on your TV. Since HD-quality disc players and next-generation consoles like the PlayStation3 will also make use of HDMI, it would be smart to make sure that your HDTV has at least one HDMI port, preferably two or even three.
The last and most often overlooked criterion is HDCP which stands for High Definition Content Protection. Even if your HDTV can support the required resolution and have HDMI cables, you may not be able to receive the HD-quality programs in its highest quality if your HDTV set does not support HDCP. HDCP is a content protection measure the movie and TV program producers make use of to prevent the unauthorized copying or distribution of their content. Therefore, only an HDCP-compliant HDTV will be able to decrypt and display an HDCP-enabled HD-program in its intended resolution. If your HDTV is not HDCP-compliant and the program requires HDCP, your video will likely be downgraded to something close to DVD quality.
HDTV: What every consumer really needs to know