Enhanced-definition television, or extended-definition television is a Consumer Electronics Association marketing shorthand term for certain digital television formats and devices. Specifically, this term defines formats that deliver a picture superior to that of standard-definition television but not as detailed as high-definition television. The term refers to devices capable of displaying 480-line or 576-line signals in progressive scan, commonly referred to as 480p and 576p respectively, as opposed to interlaced scanning, commonly referred to as 480i or 576i. High-motion is optional for EDTV. In other countries definitions may vary.
EDTV broadcasts use less digital bandwidth than HDTV, so TV stations can broadcast several EDTV stations at once. Like SDTV, EDTV signals are broadcast with non-square pixels. Since the same number of horizontal pixels are used in 4:3 and 16:9 broadcasts, the 16:9 mode is sometimes referred to as anamorphic widescreen. Most EDTV displays use square pixels, yielding a resolution of 852 × 480. However, since no broadcasts use this pixel count, such displays always scale anything they show. The only sources of 852 × 480 video are Internet downloads, such as some video games. Unlike 1080i and SDTV formats, progressive displays can show EDTV signals without the need to de-interlace them first. This can result in a reduction of motion artifacts. However to achieve this most progressive displays require the broadcast to be frame doubled to avoid the same motion flicker issues that interlacing fixes.
DVDs
The progressive output of a DVD player can be considered the baseline for EDTV. Movies shot at 24 frames-per-second are often encoded onto a DVD at 24 fps progressive, and most DVD players do the 2:2 or 3:2 pulldown conversion internally, before feeding the output to an interlaced display, or here, a progressive 576p or 480p. The progressive 24 fps DVD will have a unifying effect on PAL and NTSC, just as film does, perhaps requiring conversion of the number of lines but without a conflict between field and frame rate. The player converts the video to the more-conventional video formats, on the fly, by simply repeating each field. It converts for PAL, by repeating each frame twice with a corresponding interlace, or for NTSC, by repeating some 480p frames 2 times and others 3 times, to make 24 fps material play at 30fps, or 60 fields per second. On an EDTV display, or on HDTVs in 480p mode, DVD players can display progressive disc content without needing to convert it to interlaced format. Various signal processing tricks are then used to fake the progressive scan; the quality of this depends on the quality of the upconversion process. Blu-ray Disc and HD DVD formats can encode all EDTV forms, but because HDTV is a primary selling point of Blu-ray/HD DVDs, this is only used for certain bonus content such as featurettes, deleted scenes, interviews and behind the scenes documentaries on the making of the film.
