How To Shop For A Next Generation Disc Player
By Adrienne Maxwell
If youve just purchased an HDTV or are contemplating doing so, heres what you can expect to happen during the first few weeks with your new toy: youll connect it to your current cable or satellite box and be less than dazzled by the improvement the TV offers with standard-definition signals. Youll either purchase an HDTV antenna to pull in over-the-air HD channels, or, more likely, youll call your provider and upgrade to an HDTV package. Upon seeing a true HD signal, youll be thrilled. Youll spend every waking moment watching programs that never interested you before, just because theyre in high definition. After only a short time, youll find yourself chanting the same word the rest of us have been chanting for years: More!
HDTV enthusiasts have been waiting impatiently for a high-definition software format that gives them more content options, and it has finally arrived. That makes this an exciting time in the advancement of HDTV. Unfortunately, it also adds more confusion to an already confusing landscape. Peruse the DVD hardware aisle at your local retailer, and youll encounter several different types of players boasting high-definition quality. Youll see labels like HD DVD, Blu-ray and HD upconversion. You might happen upon a knowledgeable salesperson who can help make sense of it all, but I wouldnt count on it. So heres a brief explanation of the different formats and what each one brings to the HD table.
If You Cant Make It, Fake It If youre looking for a way to bring out the best in the DVDs you already own, and youd like to do it without spending a fortune, then an upconverting DVD player is an excellent choice. This was essentially a stopgap product that began appearing on shelves a couple of years ago to allow HDTV owners to use the higher-quality digital connections on their sets and enjoy slightly improved picture quality. There are now plenty of upconverting players to choose from, many of which sell for around $100. This feature is described as HD upconversion or video upconversion on the products spec sheet. The packaging says that you can output video signals at 1080i or 720p to match your HDTVs resolution. Thats true, which may cause you to ask, If I can output HD resolution through this $100 DVD player, why should I spend $500 to $1,000 on one of these new HD DVD or Blu-ray players? Good question. The answer is, just because an upconverting DVD player outputs video at a high-definition resolution doesnt mean it is outputting high-definition video. Confused? If so, you arent alone.
To understand what an upconverting DVD player does, lets begin with a short primer on resolution and digital television. Like standard broadcast television, DVD content is output at a 480i resolution. The picture is made up of 480 horizontal lines drawn across the screen. The i stands for interlaced, which means each video image is created by first drawing the 240 odd lines of the image, then drawing the 240 even lines. This happens so quickly that your brain sees the two as one complete image. With the arrival of pixel-based digital televisions came the progressive format, in which all 480 lines are shown at the same time. To do this, a digital TV deinterlaces the picture, or stitches the odd and even frames back together. The quality of the image is greatly affected by how well or how poorly the TV handles this task. Some early DTVs did it well, but many did not. So DVD manufacturers began incorporating the function into the player itself in other words, the player deinterlaces the image and then sends it, at a 480p resolution, to the digital TV. This feature is called progressive-scan or progressive scanning on a DVD players spec sheet. Sadly, not all players do it well, either. The trick is to make sure either your DTV or your DVD player has a good deinterlacer; DTV manufacturers now put more value in using higher-quality deinterlacers, but its not a given.
Once the DVD image is stitched back together, the next step is to match it to the TVs resolution. Thats where upconversion comes in. The TV must take a DVD signal that has roughly a 720 x 480 resolution and scale it up to its own resolution, which might be 1366 x 768, 1280 x 720, or 1920 x 1080, among others. Imagine a picture made up of tiny dots: the DVD image would have 720 columns of dots horizontally and 480 rows of dots vertically, for a total of 345,600 dots. Your HDTV has to figure out how to make that number of dots fill its screen in the case of a 1366 x 768 flat panel, the screen can render 1,049,088 dots. If you simply enlarge the image, it would look extremely soft, as anyone who has ever tried to blow up a low-resolution digital photo can attest. The TVs scaler attempts to fill in details based on the existing picture information; a better scaler does a better job of interpolating the information to help the picture look more detailed, but it still cant create new information and will in no way produce a picture that is as sharp or detailed as an image that had 1,049,088 dots to begin with. Just as DVD manufacturers began to add deinterlacing to their players, they now add scaling to their players, so you can send a scaled or upconverted image, at a 720p or 1080i resolution, to the TV. This is beneficial if youve purchased an HDTV that doesnt have a good internal scaler.
As I mentioned, a second benefit of the upconverting DVD player is that it can send the upconverted image over a digital connection like DVI or HDMI to your HDTVs digital input (if the TV has one). This lets you bypass the digital-to-analog conversion process that must take place when you use an analog connection like component video, which can introduce artifacts to the picture. The combination of upconversion and an all-digital connection path can result in a higher-quality viewing experience not a true high-definition viewing experience, but a better way to watch all of the DVDs already sitting on your shelves.