How are 144hz screen possible?
How are 144hz screen possible?
Had this reflection that 144hz screens where the only type of screen I knew, that was not a multiple of 60. 60 Hz - 120hz - 240hz - 360hz
And in the middle 144hz Is there a reason why all follow this 60 rule, and if so, why is 144hz here
With computer displays only limitation is hardware. If I had to hazard a guess, 144Hz is there because that's approximately maximum supported on widest range of hardware and 144Hz crystals were widely available and therefore cheap. Kind of how there's a huge market for rollerblade ball bearings. Pretty much all of the power tools are using them. They are simply everywhere because they are cheap.
Tell me more about the ball bearing industry please!
Haha, very little experience with that. But I do know rollerblade bearings are now most popular bearings thanks to low prices because of their initial popularity. Kind of how 18650 cell became popular because of laptops and is now virtually everywhere, including EVs. It's all playing at large scale with manufacturers.
Not sure what's the part you are interested in. I did learn about them in school, so perhaps I do have some knowledge you might find interesting.
Divide. They needed buffer room because 30 60 or 120hz aren't always exactly 30, 60, or 120hz. Like you said 144 was just the cheapest that net or exceeded spec.
LCD crystals do have a theoretical maximum, but we don’t have display drivers or transmission standards that support those frequencies.
Didn't mean LCD crystals, but just crystal oscillators that are used for timing.
72 Hz was used as a refresh rate for CRT monitors back in the day. Specifically because it was the average threshold that no users reported discomfort from CRT flicker. And 72 * 2.
It is likely a holdover from that era. I think from there, it is a multiple of 24 HZ so movie content scaled smoothly without tearing before vsync? Last part is a guess.
Old reel projectors actually flashed their light at 72Hz. They had to turn off the light to move the reel to the next slide so you couln't see the pictures moving up off the screen, and human eyes are better at spotting quickly flashing lights than they are at spotting microstuttery motion, so flashing the bulb once per frame at 24Hz in a dark room was headache inducing. The solution they came up with was just to flash the bulb 3 times per frame, which is 72Hz.
144Hz is not a holdover in the case of computer monitors. It’s the maximum bandwidth you can push through DVI-D Dual-link at 1080p, which was the only standard that could support that refresh rate when they began producing LCD monitors built to run 144Hz.
I had to scroll a bit to make sure this answer was here before I wrote the same. 👍
The reason 60Hz was so prominent has to do with the power line frequency. Screens originated as cathode ray tube (CRT) TVs that were only able to use a single frequency, which was the one chosen by TV networks. They chose a the power line frequency because this minimizes flicker when recording light powered with the same frequency as the one you record with, and you want to play back in the same frequency for normal content.
This however isn't as important for modern monitors. You have other image sources than video content produced for TV which benefit from higher rates but don't need to match a multiple of 60. So nowadays manufacturers go as high as their panels allow, my guess is 144 exists because that's 6*24Hz (the latter being the "cinematic" frequency). My monitor for example is 75 Hz which is 1.5*50Hz, which is the European power line frequency, but the refresh rate is variable anyways, making it can match full multiples of content frequency dynamically if desired.
ITT: A ton of people who think computer displays can only sync at a single clockrate for some reason.
Fun fact, quite a few monitors can be overclocked simply by creating a custom resolution. I have a 32" Thinkvision that officially only supports 1440p 60hz but it's fine running at 70hz when asked to.
the numbers are a maximum and software can alter it lower or split it up. I worked in a visualization lab and we would often mess with the refresh rates. That being said you could alter it and the screen would not respond (show an image) so there must be some limitations.
Wait until you find out why 24.9 was a standard and still is for most of the movies. Logical at the time, completely retarded today.
Is that the same reason that 30fps and 29.97 fps are two different things?
They are related. Black and white TV was running at 30 frames for obvious easy timing since USA power grid is 60Hz, but then introduction of color added two more channels and caused interference between them. So signal became backwards compatible (luminance channel was black and white, while color TVs used two additional channels for color information) but color TVs had an issue. Whole 29.97 was a result of halving 60/1.001≈59.94. That slowing down of 0.1% was to prevent dot crawl, or chroma crawl (that interference). So all of today's videos in 29.97, even digital ones, are in fact due to backwards compatibility with B&W TV which no longer exist and certainly pointless when it comes to digital formats.
On the other hand 24fps was just a convenience pick. It was easily divisible by 2, 3, 4, 6... and it was good enough since film stock was expensive. Europe rolled half of their power grid which is 50Hz, so 25... and movies stuck with 24 which was good enough but close enough to all the others. They still use this framerate today which is a joke considering you can get 8K video in resolution but have frame rate of a lantern show from last century.
It's actually 23.976 and yes it's because of NTSC frame rates. But increasingly things are shot now at a flat 24p since we're not as tied down to the NTSC framerate these days.
Well, share with the class
Did so, in other comment in this thread. :)
My iMac says it's 77hz.
60Hz was the original clock rate, determined by US power cycles way back in the day. This was 50Hz in some countries.
With LCD screens, the potential for higher frame rates became easier to achieve. They began to advertise 120Hz TVs and monitors, which set a new bar for frame rates. Some advertise 75Hz monitors, slightly better than 60Hz when crunching numbers. 75Hz is achieved by overclocking standard 60Hz control boards, most can achieve this refresh rate if they allow it. Later HDMI standards, DisplayPort and DVI-D support this frame rate at least up to 2K.
144Hz is the same trick as 75Hz, this time with a 120Hz control board. The true standard frame rate is 120Hz, it is clocked higher to achieve 144Hz. Why 144 exactly? This was most likely due to the lack of standards that originally supported higher frame rates. Dual-link DVI-D was the only one which could push 144Hz at 1080p. Any higher frame rate (or resolution) and the signal would exceed bandwidth. Now 144Hz is simply a new standard number and plenty of 1440p monitors are set to this frame rate.
Clear explanation! I assume the overclocking is the reason why my monitor goes to 165Hz.
Just to point out. I had 120hz on a CRT monitor back in the late 90s/early 2000s. The resolution was terrible though (either 640x480 or 800x600). At good resolutions (1024x768 or 1280x960) you were generally stuck with 75 to 90 at best.
60hz LCD screens were one of the reasons there was resistance among game players to move to LCD. Not to mention earlier units took a VGA input and as such the picture quality was usually bad compared to CRT and added latency. People buying LCDs did it for the aesthetics when they first became available. Where I worked, for example only the reception had an LCD screen.
Also, on a more pedantic point. 50hz is the power line frequency in the majority of the world.
That proves that the USA is 10 better than the rest of the world.
(Except American Samoa, Anguilla, Antigua, Aruba, Bahamas, Belize, Bermuda, Brazil, Canada, Cayman Islands, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Guam, Guatemala, Guyana, Haiti, Honduras, South Korea, Mexico, Micronesia, Montserrat Islands, Nicaragua, Okinawa, Palmyra Atoll, Panama, Peru, Philippines, Puerto Rico, St. Kitts & Nevis Islands, Saudi Arabia, Suriname, Tahiti, Taiwan, Trinidad & Tobago, Venezuela, Virgin Islands, and western Japan)
On your pedantic point, I can’t argue. However, I can say 60Hz power cycles are what set in stone the 60Hz standard. This is in spite of the fact that a lot of countries didn’t even have 60Hz screens until screen controller clock rates were decoupled from power line frequencies.