1080p vs. 720p

Here's a question I get a lot. This one's from Kevin Iole, a boxing and MMA columnist for Yahoo! Sports:

I have a 56-inch Samsung HL-R5667W DLP RPTV that I bought in June 2005. It's a 720p television. I wouldn't mind a larger screen, though we're happy with the picture we get on this one. But I keep hearing how great the picture is on a 1080p set. So my question is this: Will I see a significant improvement if I upgrade to a 1080p TV?

If I change, I'll either go with a Pioneer Kuro plasma or stay with DLP but go bigger with something like a 73-inch Mitsubishi. Is this change just throwing money away, or will we see a significantly better picture?

In terms of apparent detail, I suspect you won't see that much difference between 720p and 1080p—with good displays, both look great, even at moderately large sizes. On the other hand, as the screen gets much larger, the visible difference in detail between 720p and 1080p displays does become more apparent. This might be a moot point, since it's getting harder to find anything other than a 1080p display larger than 50 inches these days.

There is one factor that is often overlooked: Most HD content, including Blu-ray and most broadcast, cable, and satellite HDTV, has a resolution of 1920x1080. Blu-ray delivers its content with a 1080p signal, while broadcast HD is delivered with a 1080i signal, but both have a pixel resolution of 1920x1080.

When either type of signal is displayed on a 720p TV, the set must scale, or resize, the image to fit into the 1280x720 pixels of the display. Depending on the quality of the TV's scaler, this can result in visible artifacts that can be very distracting, even on small screens. I don't know if the Samsung you have does this scaling well or not; if you see artifacts such as softness or ringing (halos around sharp edges in the picture), it's not doing a good job.

By contrast, 1080p TVs avoid the whole issue by displaying all 1920x1080 pixels without scaling the image—that is, if they have a so-called "1:1 mode" that disables any overscanning. Look for this critical feature in any 1080p display.

I think the Kuro plasmas are among the very best video displays available today, so you can't go wrong there. But they are also very expensive, especially the 60-inch models, which is what I assume you're considering. The 73-inch Mitsubishi is probably good, but I haven't looked at one closely yet.

How far are you sitting from the screen? This is perhaps the most important factor in determining the best screen size for your situation. At a distance of 10 feet, a screen size of 73-90 inches (diagonal) is usually considered ideal for high-def images. At these sizes, you probably will see an improvement in detail with 1080p compared with 720p. On the other hand, there are no 720p displays available at this size, except for front projectors.

If you have an audio/video question for me, please send it to scott.wilkinson@sourceinterlink.com.