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1920*1080i or 1920*540p

1112 Views 10 Replies 6 Participants Last post by  gomo657
whats the difference between the two? I have a upconverter capable of both.

I understand the difference between interlaced and progressive but whats the difference between these?
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Which looks better thru your setup? Use the one that provides the cleanest picture in your exact setup.
I've just been watching Desperdo SB and I'm having a hard time telling the difference. 34" crt BTW
How are you feeding the signal to the CRT?
via component. I was hoping one of the many tech savy would give an explanation.
What is the distance from the TV to your seating position?

1080i and 540p in analog form are approximately the same and usually interchangeable.

1080i source has picture detail captured from 1080 (x up to 1920) possibly positions in the scene. 540 source has picture detail captured from 540 (x up to 1920) possible positions in the scene.

1080i analog format has 1125 total scan lines per full frame and encoding somewhere in lines 1081 throuth 1125 indicating which field is odd and which field is even. I think 540p analog format has 1124 or 1126 scan lines for every two frames and no way of identifying some frames as odd fields.

1080i on the screen has picture information on 1080 unique scan line positions (i.e. pixel rows) on the screen. 540p has picture information on 540 unique scan line positions on the screen. A TV with those settings can be set to either 540p or 1080i for material originally at or converted to either 540p or 1080i. Depending on the electron beam fatness you may see more pronounced gaps between scan lines when you switch a CRT HDTV to 540p.
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thanks for the info. I think I'll stay with 1080i IMO it looks smoother not necessarily more detailed just smoother.
Way back, when the 1080i and other ATSC formats were tested for approval, a committee of video experts measured 800 lines of effective vertical resolution with the 1920X1080i format. A setup that only uses 540p, such as bob-only deinterlacing, obviously can't deliver 800 lines. (The sublink for the original data source, table 2.3, no longer works, but is now a pdf ATSC link .) Also, the intro "resolution" paragraph (2.1) in that ATSC link mentions that 540p tends to look like 1920X1080i when motion takes place. Motion, as the first linked test table above shows (dynamic data), sharply reduces interlaced vertical resolution. But progressive images aren't necessarily a cure for vertical resolution loss with motion, as the test data for 720p shows, as well as some authoritative sublinked articles outlining resolution for both HD formats. -- John
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thanks for the links John
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