This is a FAQ intended to answer general questions about HDTV features. If you have any suggestions, corrections, or general comments you can post them on the sticky thread for FAQ discussion.
While there's no unified definition of what qualifies as HD, for consumer purposes you can think of a HDTV as a TV that has a resolution of 1024x768 or higher. Traditionally not all digital televisions (DTVs) are HDTVs or HD ready displays, but at the present time most are. Beware of EDTVs, which feature resolutions compatible with anamorphic DVDs instead of actual HD resolutions. Although these TVs are still capable of receiving HDTV broadcast signals, they won't give you the same quality as the lowest resolution HDTV.
HDTV Signals HDTV can also refer to a digital television (or other digital video) signal. Although the TVs themselves come in a variety of resolutions, only two of them are used for broadcasting - 1280x720 (720p) and 1920x1080 (1080i and 1080p). While a TV with a resolution of 1024x768 is designed to accept 720p signals natively, and one with a resolution of 1366x768 is designed for 1080i, in both cases the image is scaled to match the display.
Camcorder Resolutions In addition to 1280x720 and 1920x1080, high definition camcorders may use a different 1080i resolution of 1440x1080. Unlike standard 1080i (1920x1080) where the pixels are square, 1440x1080 uses rectangular pixels to achieve a widescreen image at a lower horizontal resolution, and therefore with a lower file size.
Widescreen All HDTVs are widescreen, meaning they have an aspect ratio (AR) of 16:9 or 1.78:1. Old fashioned analog TVs have an AR of 4:3 or 1.33:1, which is referred to as fullscreen. Some TVs claim to be HDTVs, but have a fullscreen AR. This means they'll have to letterbox standard widescreen HDTV broadcasts, just like on a SDTV. While the quality will still be superior to a SDTV, it will be inferior to a true (16:9) HDTV.
This picture shows a fullscreen image on a widescreen TV. Notice the black bars on the sides. This is because of the different aspect ratios.
