What are the HD standards available?
The main HDTV standards which are on offer in the UK are called 720p and 1080i. 720p will show 50 frames per second (fps) each with 1280 by 720 pixels (When specifying the frame rate the standard may be written as 720p50 or 720/50p). The “p” stands for progressive to distinguish it from the interlaced standards with an “i”. The interlaced standards show only every alternate horizontal line of the image for each frame so it takes two fields to cover all the lines. 1080i is an interlaced standard with 1920 by 1080 pixels and will be transmitted at 50 half frames per second in the UK (i.e 25 frames split over 50 fields). When specifying the frame rate these should be written as 1080i25 or 1080/25i (Often this is incorrectly written as 1080i/50 or 1080/50i.) Both standards use an image aspect ratio of 16/9. In the US a faster frame rate of 60 fields/sec is in use but the EBU (European Broadcasting Union) have chosen the slower rate of 50 fields/sec for Europe. It is possible that DVD, comp
