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dbmaven
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4 edits

7 recommendations

The "is it 1080p" conundrum...

There's immense confusion and disagreement as to what "1080p" really means.

Without getting into too many technical details, here is a summary:

1080p is a display resolution standard - representing 1920 horizontal x 1080 vertical pixels in a Progressive (i.e. not interlaced) format. Anything that is progressive scan (all of the lines are drawn in sequence in a frame) at 1080 lines top to bottom (vertical resolution/horizontal lines) qualifies as "true 1080p".

The frame rate defines how 'often' a display (or for that matter, capture) device produces unique consecutive frames. It is usually referenced in fps (frames per second).

Movies have been traditionally shot on film at 24fps. Major players (like George Lucas from Star Wars fame) have transitioned this 'standard' to the digital era - so nearly all "movies" are shot, even today digitally, at 24fps. This is the 'production' standard. Video (i.e. videotape) has tended to be 30 fps, but varies.

ATSC and DVB broadcast standards support 1080p resolution at 24, 25 and 30 fps.

Once you've got the material to a display device, you then have the problem that most panels operate at 60hz (e.g. 60fps) - so something is needed to translate the signal from it's source format into something the display can understand and output. Hence, the creation of 3:2 pulldown and reverse 3:2 pulldown - allowing a 24fps source to be 'properly' displayed on a 60fps device.
(very detailed information about the telecine process and 3:2 pulldown can be found here.)

One of the reasons why some LCD makers are now touting "120hz" devices is because it is a perfect multiple of 24 - where what's called a 5:5 pulldown can be used - more efficient than 3:2 and less error prone).

Summary: 1080p is a resolution. Anything that's displaying 1920x1080 progressive pixels is true 1080p.
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needforspeed59
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Thanks, DB!



Hayward
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4 edits
reply to dbmaven

said by dbmaven:

One of the reasons why some LCD makers are now touting "120hz" devices is because it is a perfect multiple of 24 - where what's called a 5:5 pulldown can be used - more efficient than 3:2 and less error prone).

Summary: 1080p is a resolution. Anything that's displaying 1920x1080 progressive pixel/lines is true 1080p.
Nice definition, but any slightly tech head should know....

And by the way that is how "Film Chains", film projectors in to 30 fps NTSC TV cameras for direct film broadcast on television worked.... rather than single shutter blades the projectors had 5 blades spinning by in the single frame rate... again like 120hz frame rate , 5 times 24 (in mechanical terms) is 120/even multiple as well... so no flicker, and normal look. WHen still working at a TV station, converted old 16mm home movies to video that way... even though 16 fps (the silent standard... 24fps was chosen for sound quality as well as less perceived flicker), but took them to 1" tape in between which had clean variable time base corrented speed, so could get the 24fps procetion, back to 16 fps effective cleanly.

And actually, if those film chain cameras had a silent speed slowed to 15fps rather than 16, then I could have done it directly as that would also be a even multiple of 30, and not really look slow... but they didn't.
Actually a bit better, while some say they can see 30fps flicker I definately can 24 fps when a bright panning scene in the theater... but with even NTSC the 6more fps, and the phosphor persistance, much smoother looking. And agian those old 16mm home movies, with none of the perceived flicker you you definately physically projected at 16fps. (though nothing the interferance/frame rate mismatch flicker you see of film converted to video without compensation)

The 120hz frame rate is more necessary perhapes because modern LCD and Plasma does not have the persistance lag that old CRT phosphors did. (Also why early LCD monitors were resisted for video gaming, until vid card frame rates were upped) Though I havent really noticed it on a 42" HD LCD, I ampretty sure is only 60hz, though might be 120hz in 1080p, my DISH SD, passing through DVD-R is upconverted to. (Looking much better than the S video directly into the TV just doing 480 conversion)
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dbmaven
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said by Hayward:

Nice definition, but any slightly tech head should know....
Thanks. The problem is that there are lots of non-"tech heads" - and that's who this was written for.


wings10
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reply to dbmaven

Very nice db!!



Hayward
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reply to dbmaven

said by dbmaven:

said by Hayward:

Nice definition, but any slightly tech head should know....
Thanks. The problem is that there are lots of non-"tech heads" - and that's who this was written for.
Hense the word even "slightly" like anyone that pays attention to what they are actually buying even.
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darcilicious
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said by Hayward:

said by dbmaven:
Thanks. The problem is that there are lots of non-"tech heads" - and that's who this was written for.
Hense the word even "slightly" like anyone that pays attention to what they are actually buying even.
Everybody has to start somewhere -- and this post seems like one of those good starting points


wings10
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said by darcilicious:

Everybody has to start somewhere -- and this post seems like one of those good starting points
I agree.
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Hayward
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4 edits
reply to darcilicious

said by darcilicious:

said by Hayward:

said by dbmaven:
Thanks. The problem is that there are lots of non-"tech heads" - and that's who this was written for.
Hense the word even "slightly" like anyone that pays attention to what they are actually buying even.
Everybody has to start somewhere -- and this post seems like one of those good starting points
But a little self educ. never hurts....

Just like those that buy a $20K less car but supposedly just like a super BMW... but in the end isn't.

Buyer should self educate themselves. I actually returned a HDTV misrepresented, as 1080p when actually just an down-converting 720p, 1080i compatible set (still 720 image though )

Took a little back and forth but thank you MacWorld accepting the refusal and for for in the end sucking up the $95 shipping charge too (for full refund), after realizing someone just screwed up in the site prod description... though they had already corrected before even shipped, but never notified me... do you still want this inferior version.

And I know how the mistake likely happened a one letter dif in same model number... old and new the same model but 720 being mod# HD, vs the 1080p being same mod # FHD. (FULL HD)

I already HAD a smaller 720 HD, I wanted a larger true HD 1080p understanding the difference.

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»haywardm.com (Hayward's Key West)


wafen
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said by Hayward:

But a little self educ. never hurts....


And if they do a search maybe this thread will come up and this will be their self education.
Any post with good information is useful. You may know the information, but others don't, so let's let them learn it with out chastising them for not learning it before coming here.
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wings10
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said by wafen:




And if they do a search maybe this thread will come up and this will be their self education.
Any post with good information is useful. You may know the information, but others don't, so let's let them learn it with out chastising them for not learning it before coming here.
I agree. Well said!!!
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Hayward
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reply to wafen

said by wafen:

Any post with good information is useful. You may know the information, but others don't, so let's let them learn it with out chastising them for not learning it before coming here.
I don't believe I chastised anyone... name calling, etc... though maybe saying all too many do go for the coolness glitz, and low price, over actual researching something they are buying, and then say why is it not right.
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MacLeech
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1 edit
reply to dbmaven

said by dbmaven:

There's immense confusion and disagreement as to what "1080p" really means.
Now can you explain to the "non-techies" the differences they may notice between 1080p24 and 1080i30, since resolution is the same?


wings10
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reply to Hayward

said by Hayward:



I don't believe I chastised anyone... name calling, etc... though maybe saying all too many do go for the coolness glitz, and low price, over actual researching something they are buying, and then say why is it not right.
My god your amazing. They create a thread with information and you have to jump in and slam it like all the others.

You say people should go out and do research. Well isn't reading this thread research?

But I guess you want people to look else where for information and not here. Unless of course it is you that is giving the information.

Why not just stay out of it.

Another useful thread polluted.
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Hayward
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4 edits

My first post, 3rd in thread is not frame rate related INFO??? Bringing in the motion factors, that go along with it, especially anyone into fast sports, where the 120hz refresh would be important, and why that is even if the broadcast rate is still 60hz. Might be worth the extra state of the art cost.

While cheaper 60hz would be fine for most interested in mostly normal speed things.

Yes hopefully the thread is useful info for those who haven't leaped yet, to cheap (for a reason... being dumped) 720p supposedly 1080 but really just down converting disappointments
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JSY
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Elmhurst, NY

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reply to dbmaven

This thread consisted more of "why people should self-educate themselves" than the actual subject itself. While I consider myself more than slightly techie - I think it was a nice gesture for the OP to lay it out there for other people. And frankly, I don't think most people know what 120hz other than the store telling them that it makes things "smoother".

Yes this thread started off useful. Then sort of went off on a tangent there.



joe01880

join:2007-10-26
Wakefield, MA

1 edit
reply to dbmaven

Below please find a direct link to a 7 page article that gives all the explanation of HD,720p, 1080i and 1080p, 24 Hz and 60Hz that anyone will ever need in easy to understand terms.

Enjoy!

»www.hometheaterhifi.com/volume_1···t-1.html



NY Tel
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reply to darcilicious

said by darcilicious:

said by Hayward:

said by dbmaven:
Thanks. The problem is that there are lots of non-"tech heads" - and that's who this was written for.
Hense the word even "slightly" like anyone that pays attention to what they are actually buying even.
Everybody has to start somewhere -- and this post seems like one of those good starting points
Yup, I for one, thought it was an excellent post.
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