# 1080p



## whatchel1 (Jan 11, 2006)

Broadcast Engineering Article

1080 60p and beyond &#8230;

Nov 18, 2006 8:00 AM, By Philip Cianci

http://broadcastengineering.com/hdtv/1080P_60p/


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## James Long (Apr 17, 2003)

Good article. It even supports my preference (as a format) for 1080/24p (which matches the frame rate of movies ).


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## wje (Mar 8, 2006)

One thing I wonder about is flicker with the 24p frame rate. I can't watch PAL/SECAM transmissions because the flicker is so bad, and that's a 50i (or an effective 25p) frame rate. Of course, the flicker is made noticeable because of the scanning of the image done by CRTs. That's why (real) film isn't objectionable... you see the full frame all at once, not scanned.

Anyway, any comments or experience with this?


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## AllieVi (Apr 10, 2002)

I've never understood the rationale of decreasing the frame rate. If anything, I'd like to see it *increased* so that what I see is closer to reality.


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## William (Oct 28, 2006)

AllieVi said:


> I've never understood the rationale of decreasing the frame rate. If anything, I'd like to see it *increased* so that what I see is closer to reality.


60fps or higher would be great but we are stuck with a legacy format called film that is 24fps. 24fps was picked for film because it was the least amount (less film used) that could be used and still provide smooth motion. If and when Hollywood switches to a digital standard at a higher film rate (so far all digital "film" still uses legacy 24fps for production reasons) we will still have all the current films at 24fps so it will be with us forever.

I have a iScan VP50 which can take 1080i film based and reconstruct the original 24fps. It then outputs at 24Hz or 48Hz. I use 48Hz on my HD10K and this eliminates judder.

I doubt we will ever have 1080p over satellite because of bandwidth constraints and limited HDTV input compatibility


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## whatchel1 (Jan 11, 2006)

wje said:


> One thing I wonder about is flicker with the 24p frame rate. I can't watch PAL/SECAM transmissions because the flicker is so bad, and that's a 50i (or an effective 25p) frame rate. Of course, the flicker is made noticeable because of the scanning of the image done by CRTs. That's why (real) film isn't objectionable... you see the full frame all at once, not scanned.
> 
> Anyway, any comments or experience with this?


I don't think there is a good comparison of the PAL analog TV scan and the digital 24p rates. Digital frame 24p is closer to the rates that film is projected at than TV scans. There will be 24 full frames being projected as opposed to 50 frames interlaced. Part of the flicker problem has to do with the fact that the images have to be interlaced together to make a picture. The full picture is there in a 24 p progressive scan frame.


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## James Long (Apr 17, 2003)

If they could build a set that would change all of the pixels at the same time it would help. Then you wouldn't have the top of the screen changing before the bottom by a fraction of a second.


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## rbonzer (May 13, 2002)

Also, it only has to be 1080p 24fps for the transmission. There is nothing that says your CRT can't show it as 72fps. Its not like showing the movie as 60i was going to get you more frames of the movie. Give us the 1080p 24fps and let the display figure out how to show it.

Rob



wje said:


> One thing I wonder about is flicker with the 24p frame rate. I can't watch PAL/SECAM transmissions because the flicker is so bad, and that's a 50i (or an effective 25p) frame rate. Of course, the flicker is made noticeable because of the scanning of the image done by CRTs. That's why (real) film isn't objectionable... you see the full frame all at once, not scanned.
> 
> Anyway, any comments or experience with this?


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## Larry Caldwell (Apr 4, 2005)

wje said:


> One thing I wonder about is flicker with the 24p frame rate. I can't watch PAL/SECAM transmissions because the flicker is so bad, and that's a 50i (or an effective 25p) frame rate. Of course, the flicker is made noticeable because of the scanning of the image done by CRTs. That's why (real) film isn't objectionable... you see the full frame all at once, not scanned.
> 
> Anyway, any comments or experience with this?


Solid state displays don't flicker. They use entirely different display technology than film or CRT. A pixel stays lit until it is refreshed.


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## Jim5506 (Jun 7, 2004)

James Long said:


> If they could build a set that would change all of the pixels at the same time it would help. Then you wouldn't have the top of the screen changing before the bottom by a fraction of a second.


DLP, IDLA, LCD - all digital displays display the whole frame at the same time, no scanning.


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## James Long (Apr 17, 2003)

How do they refresh the pixels? All at once (same millisecond) or are they refreshed as new data arrives?


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## harsh (Jun 15, 2003)

Jim5506 said:


> DLP, IDLA, LCD - all digital displays display the whole frame at the same time, no scanning.


Technically 1080p DLP is rapidly flipping back and forth between adjacent pixels as the mechanical mirror matrix is only 960x1080. DLP also offers the complication of a color wheel that requires that the "pixel" be lit only while the correct color(s) is(are) hitting it


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## harsh (Jun 15, 2003)

Larry Caldwell said:


> Solid state displays don't flicker. They use entirely different display technology than film or CRT. A pixel stays lit until it is refreshed.


That is not true at all. Pixel timing is very carefully modulated to vary brightness (and color in the case of the single chip microdisplays).

I think I read somewhere that the scan rate for a modern display was on the order of 120fps.


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## whatchel1 (Jan 11, 2006)

Here is the rates and how they ar3e handled according to the Wikipedia. 
http://en.wikipedia.org/wiki/1080p


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