It's an age old misunderstanding that even yours truly has even been susceptible to. EDTV disguised as HDTV – or is it? This article has been edited to set the record straight and help in the understanding of digital TV resolution and aspect ratio.
The ad below was taken from a flier of a major electronics chain. The ad shows a display resolution of 1024x768 being sold as HDTV.
1024 x 768 falls well short of 1280 x 1024 resolution, a generally excepted 720P resolution. This doesn’t sound possible.
Chris from Big Picture Sound points out that digital displays with a 1024 x 768 resolution can still technically be considered HDTV.
How is this possible? HDTV must produce an aspect ratio of 16:9 (16 pixels wide for nine pixels high). The math just doesn’t add up! You’re losing some 256 lines of resolution.
If all the pixels in a digital display (as they are in a PC monitor) were round or equally proportioned - the set advertised in the banner could not be widescreen with a 1024 horizontal resolution. You would indeed be getting short changed 256 lines of horizontal resolution.
The 4:3 aspect ratio is that of Standard Definition TV. Broadcast HDTV will not fit into that screen and DVD movies marked ‘widescreen’ will have to be corrected with those annoying black bars.
It might fit the definition of EDTV, televisions with enhanced resolution that don’t fit the standards outlined for HDTV. You can sometimes get these sets at a discount, making its price attractive to consumers who might be in the market for a new TV but necessarily married to the idea of an HDTV.
But make no mistake you can get 1024x764 to present widescreen. As Chris points out they do it with rectangular (long) pixels which is quite common for Plasma in the 42" range.
Personally, I'd feel short changed buying a set with less than the standard widescreen 1280 horizontal pixels. But you have to trust your eyes when looking at the quality of the image – don’t simply rely on the numbers.
