What do all those numbers and letters mean on my Blu-ray discs and HDTV?
Ah, the numbers and letters. We’re trained to think that larger numbers are always better, and they are–sometimes. We’ll come back to that in a second. First, let’s start with the basics. When you watch television, the picture you see is made up of many scanned lines that compose the image on the screen. Lines of resolution vary for different digital televisions–480, 720, and 1080. The more lines you have, the clearer the image. Interlaced and progressive are the two scanning techniques that are used–that’s where the "i" and "p" come in after each number. As a rule, progressive images tend to look better than interlaced, since interlacing is a holdover from the old picture-tube TVs, so a 1080p image will look better than a 1080i image. Most high-def programming today is 1080i, which still looks great, but it’s not the highest possible resolution. DVDs are 480p and Blu-ray discs are 1080p.
Now here’s where it gets confusing. The image you see is determined by a combination of the resolution of the content and the resolution that your HDTV will support. So if you play a standard DVD at 480p on a 1080p HDTV, you’ll see the image at 480p–it’s limited by the resolution of the DVD. By the same token, if you play a 1080p Blu-ray disc on a 1080i HDTV, you’ll see that movie in 1080i–since it’s limited by the resolution of the TV. So when you’re looking for a new TV, you should consider the resolution of the content you plan to feed into it. 1080p HDTVs are still the most expensive, but as prices come down and as more content is produced in this high resolution, you’ll want to combine 1080p Blu-ray content with a 1080p HDTV.