576p is the shorthand name for a video mode. The p stands for progressive scan, i.e. non_interlaced, the 576 for a vertical resolution of 576 lines, usually with a horizontal resolution of 720 pixels and an aspect ratio of 4:3; that is standard_definition television (SDTV). The frame rate (in this case equal to the field rate) is usually 25 or 50 Hertz and can be given explicitly after the letter. It is usually used in former PAL or SECAM countries for these can be 576p25, but analogue. With doubled temporal resolution, 576p50 is considered enhanced-definition television (EDTV). It can be transported by both major digital television formats, ATSC and DVB, 576p25 also on DVD.
So a 576p projector needs to take that 480 lines of information and redistribute it over 576 lines, a process which is called scaling.
That is because the HD signal, which is either 1920x1080 or 1280x720, is being compressed into an array of 1024x576 rather than the lower resolution 854x480 array.
So on a 576p projector everything must be scaled in a manner that represents an unattractive compromise for both standard definition and high definition sources.
Nov 17 2003, 06:37 PM 576p is Channel 7's version of HD (albeit officially HD according to the Aussie Standard).
For upconverted HD broadcasts, whether you use 576p or 1080i is probably a personal preference because the picture is similar.
The 1080 pSf material is converted to 576p for HD transmission with a high quality converter which retains the progressive nature of the source material without the artifacting and resolution loss you'd see with de-interlacing conventional 576i50 source material.
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