HD1080i De-mystify HDTV 1080i ::: know why before you buy

Monday, November 12, 2007

1080 at 120hz - enabling tech

120HZ? twice the speed you need..,?

Take the 120hz refresh rate HD1080 displays currently offered, marketing themselves as "better" for sports viewers. This is a bit nuts since all broadcast HD is 1080i meaning interlaced frames at a full frame display of 30 ( actually 29.97 ) frames per second. If you have a flatpanel display this means it gets 1/2 of the lines it needs to make an emage each 1/60th of a second, the other half in the next 1/60th of a second. What most people dont get is that this makes for a "temporal arrival" of 1/2 of the frame content each 1/60th of a second, and therefore the firmware can in fact produce a complete image every next 1/60th of a second by incrementally performing adaptive de-interlacing in its buffers. The best display therefore is 60hz frame rates from reconsctructed data incrementally getting half its frame ( every other line ) on a continuous basis.

Flat = Progressive.
If you have an LCD/DLP,Plasma whatever HD system then your best display rate is 60 frames for each second, or 60 hertz (60hz), since all flatpanels are really computers with frame buffers that can only display a completed full image at some display rate.

Its that computing power that amazes me, and this is part of what 120 hz is cool that is not self-evident unless you are an HD content editor shooter & producer (me)... mostly due to the fact that you wont see the situation for all that it is unless you work with HD cams and editing and have the stuff it takes. ( the wife calls it "wires and junk" but i call it "cool" )

DELAY TIME - what you see is what came in .267 seconds ago.

What you see on your HD screen is delayed by the processing time it takes to build a frame, some systems are slow and the frame processing is evident ( when i connect my HD camera and look at the LCD in the cam and the HD display at the same time i can see the lag time on the HD screen ) Why does this lag time matter? Well it really doesnt, if you are watching sports like a couch potato, you are basically absorbing stream data and not interacting with it. zzzzz... i know that sounds a bit techbabble but thats what it is, 120hz refresh is basically lots of processing headroom in the display and it will deliver a better image when a better image is what is coming into it.

So for you sports fans, 120hz frame rate screen refresh is of minor esoteric consequence in wanting HD sports that only changes its frame content at 60hz anyhow, granted its a bit smoother... but unless you are side-by-side comparing slow and fast screens, you really dont much see the kick any differently. HD1080i is what you get and what there is and thats 29.97 frames per second.

120HZ HD for Interaction.

120hz matters when you have a superpowerful HD system you must interact with, and the response time should be instant through the entire path of processing, no lag , no delay, very fast. Something the Ps3 promises and should be able to do, sometime in the very near future... ( not today though ).


Real Depth -- Here is where 120hz displays can do stuff that no other system could do. 3-D ocular managed stereovision fully dimensional rendering and processing. wow cool what the hell is that...? Basically Stereo vision from a single source, same scene shown from 2 angles, in computing CGI this is really getting the bang for the buck in 3-space modeling... in the delivery though its been all but flickery and clunky unless things are HD and very fast.

For a proper 3D system to work, it should produce a different frame for each eye. Good ones do that at 60 times a second. At 120 hz refresh you now can show each eye its own frame sort of. Since human retinal latency is what it is ( image persistence in your vision ) 60hz flicker looks like constant light. By way of example, flourescent lights blink at 60hz and if your retinal latency was really fast, you would realize that those bulbs actually flicker a bit (bulb phosphors smooth that out but thats what it is ) with a 1/60th of a second full on-time. Old CRT tubes are the same. Ok Mr Wizzard....wave your hand quickly in front of an old tube TV screen and you will see the strobe effect. Take it for granted...Movie theaters are 24 frames per second, and we are used to that also, brighter images last longer in retinal latency so its all good. Go see an IMAX 3D and you will for sure know what all this babble is about. Just ignore the bad eyewear.

It doesnt have to be this ugly - the goggles were IMAX toying with the new film "deep"

I have no clue who that girl is.

120 hz speed of refresh lets us basically enable 3-d at HD resolutions for smooth display of each eye at 60hz, and its how the next generation of dimensional game interaction is possible, and you can do things no IMAX camera can do. Get drastic, think maximum immersion. Blow your mind a bit with stereo cgi. If you see this stuff for even a few seconds your mind will be forever altered.

Ideally a video game is an interactive movie ( actually both, watch play machinimation, i like video games to be movies since the story-telling is a powerful form of engagement) The Smart Money is on those people -- Gamers and Movie makers -- that understand Video Game worlds and take everything a step further.