Quote:
Originally posted by Archangel
Mfusick,
If it is sending out a 1080i signal....I was always assuming that it is also sending a 1920i signal attached....and it is your display system that scales it down to it's native resolution. Please explain.
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At first people thought that 1080i was better than 720p because although there was less lines horizontal (540) if you looked at one field, there was more pixels or picture information on each line (1920)
This is actually not true.
In theory, 1080i should provide a superior image in terms of detail, since 1080ix1920 contains more "active" pixel elements than 720pX1280 does.
Even if you look at a field of video and not a frame, (two interlaced fields make a frame)1080i on paper looks better.
One field of 1080i is- 540 lines by 1920 pixels for total of 1,036,800 pixel elements. (right?)
One field of 720px1280 is 921,600 (720x1280)
Now, since our eyes can be fooled into thinking we see all 1080i of the interlaced lines at once... 1080i does indeed contain more picture elements than 720p does. Also, the first 540 lines don't have to be exactly the same as the second set of 540 lines, where 720p this is the case.
Now for reality,
There is not really any 1080ix1920 signals available. As posted earlier, due to current limitations from certain brands of HDTV recorders, cameras, and broadcast station links to local networks really the most you get is about 1080ix1454 or so.
Now try the math out again...
One field of 1080i now give you 540x1440 = 777,600
While, 720px1280 still gives you 921,600.
Take into acount that 1080i has more interlaced artifacts and picture noise, and 720p seems superior.
Particuarly if you extend this to a full frame of video, where as much as 30% (according to Mr. Joe Kane) of the interlaced resolution can be lost in the conversions from progressive to interlaced to minimize the visibiity of interlaced artifacts, which 720p again does not suffer from.
If you take the full frame (two fields) 720p looks alot better because now you have 1280x720x2=1,843,200 active picture elements and resolution in both horizontal and vertical directions remains constant over time, where 1080x1440 (540x1440x2) only gives you 1,231,200 active picture elements.
1,843,200 minus 1,231,200 = 612,200 more active elements of the picture in 720p, along with the absence of interlaced artifacts.
For me,
Spending all that money on a Toshiba LCOS mostly because toshiba claims it can do 1080iX1920 makes no sense at this point.
By the time the stations, cameras, recorders and broadcasters can supply us with real 1080ix1920 material the toshiba LCOS would be old technology and perhaps Sony's 1080p system will be out, and cheaper.
Buy a $3000 CRT RPTV now that can do 1080ix1400, that has better blacks and colors and contrast ratio now...
Spend another $3000 in a few years when the 1080ix1920 signal is out there to receive on a TV that is superior to the LCOS now...
And, Donate that old CRT pig to a church or school and deduct the cost on your taxes....
