Why is HD 1080p? | Nostalgia Nerd

[Music] ay where do we start on this one the beginning always the beginning in this instance that beginning is 1940 honestly why do I do this to myself I could just say it's 1080p because of this but no no I have to create an entire bloody history lesson but before I get started there are a couple of ways you can support the channel the first is to grab my latest book Nostalgia nerds gadgets gizmos and gimmicks an essential guide the personal Tech Through the Ages the second is patreon there you'll find various tiers including Early Access producer credits and a whole lot more of course just watching is support enough so without further Ado let's get back to it in 1940 the national television committee was established by the United States Federal Communication Commission and it had one purpose to resolve the conflicts between private companies who were attempting to deliver television Across the Nation in 1939 RCA had already begun broadcasting their MBC TV network across New York and Los Angeles which relied on bulky television receivers produced by General Electric and designed to receive 441 lines broadcast by NBC however Dumont one of the Pioneers in extending the life of Cafe Ray tubes had their own television station W2 xvt very C and were campaigning to increase the number of broadcast scan lines to between 605 and 800 greatly improving the resolution of TV pictures the committee would eventually settle for a compromise suggested by the radio manufacturers Association of 525 or 486 visible scan lines split into two interlaced fields of 262.50 lines 30 times per second adopted Nationwide this would remain the black and white television standard until 1953 when the ntsc color television standard was introduced reducing the scanning frequency to 29.970 frames per second with the remaining bandwidth used to carry the color signal other parts of the world would have their own stuff going on for example here in the UK and other parts of Europe our power system was devised to improve on the shortcomings of ntsc with one of those being an increased vertical resolution to 625 lines with 500 76 visible lines and like ntsc the rest were reserved for retrace and sync data although due to our 50 HZ electrical system this was broadcast at a slightly lower frame rate of 25 per second which is half of our 50 HZ rate these standards would persist pushing signals to our 4x3 televisions for the remainder of the century however in the ' 70s a new form of Technology arose and it had the arduous task of interfacing with television sets but were not really designed for its arrival ah yes the home computer humble yet powerful limited yet mindblowing in its potential machines like the Vic 20 Sinclair zx80 and even game consoles like the Atari VCS had to effectively act as mini TV broadcasting stations so they could display pictures on your television set but they had to rely on a few tricks to make this possible and importantly usable although standards like ntsc and power had a set number of scan lines they really didn't have any fixed horizontal resolution it was mainly limited by the signal bandwidth and the ability of the TV receiver for practical purposes there were technical targets which equated to about 338 tvl for ntsc and 403 tvl for pal tvl standing for television lines defined as the number of vertical lines that can be discerned usually this is affected by the broadcast signal bandwidth Fidelity TV receiver and the grill the electron gun fires through the lines you see going up and down here are just that the aperture grill or Shadow mask behind the glass used to focus the electron beams onto the phosphor this dot pitch does affect the pitcher quality giving a forced horizontal resolution but is not tied to the broadcast signal interestingly the human eye is more sensitive to Vertical resolution but B horizontal so although this is lower than you might expect it was helped in part by the natural anti-aliasing effect of CRT screens although analog signals or CRT displays for that matter don't have a fixed horizontal resolution a computer being digital can however a computer especially at the time had a limited amount of RAM and therefore the number of pixels and thusly resolution it could display were limited many computers of the time would therefore display in something like one 60x 200 or 320x200 far lower van could be discerned on your TV set whilst also foro interlaced scanning to save memory and processing time which also meant they could only access half the screen's vertical resolution each pixel effectively taking up two horizontal lines in the sense of a computer then a pixel is a logical rather than physical unit the smallest addressable block on screen as defined by The Machine's ROM and screen mode you could in theory have a 1ex one resolution screen but still takes up the entire screen it's just one single color addressable block as more powerful computers came along with more memory and faster processes their abilities to display higher resolutions increased and although machines like the Amiga could display pretty high resolutions through a TV set the number of horizontal lines or vertical resolution was a hard limit which when interlaced would be particularly flickery and the horizontal Fidelity was keyed to bandwidth the dot pitch of a shadow mask and phosphor density which could vary from set to set therefore dedicated computer monitors would become more widely adopted something that professional machines such as the IBM PC compatible had already been using since their Inception unlike television signals monitor signals are progressive meaning each line is drawn in order with no interlacing giving a more stable image also unlike televisions monitors could have their own refresh rates and the ability to scan the image onto the screen at different rates allowing for different resolutions compared to our modern LCD monitors CRT monitors didn't have a set number of physical pixels but they still had a maximum number of pixels they could draw on screen early PC graphics standards would more or less mimic the resolutions of TV based systems but by 1987 something more usable was required and so IBM introduced the VGA Monitor and VGA graphics card with their PS2 line of computers offering a resolution of 640x 480 within 3 years this was the standard display type among PC users which was quickly improved upon by thirdparty manufacturers into a de facto standard that became known as super VGA but just like the TV broadcasters before lack of compatibility between these graphics cards and screens meant something needed to be done to ensure they could could be universally programmed for this time it was the video Electronics standards Association that would create a common software interface for all cards which conformed to their vbe specification this and subsequent specifications would standardize the following resolutions 800x 600 1024x 768 also known as XGA and finally 1280x 1024 also known as super XGA an actual Step Up in resolution that all conformed to the 4x3 viewing ratio of monitors at the time well apart from 1280x 1024 that was for the 5x4 crew who emerged a bit later however whilst computers were doing their own thing the TV buffins were not at rest and anyone who has watched my video on aspect ratios will know where this part A pil begins [Music] way back in 1972 Japan proposed a new cciir study program to work on an analog highdef television system ultimately utilizing 2D filtering do interlacing motion Vector compensation line sequential color encoding and time compression it managed to cram a 20 MHz analog bandwidth Source signal into just 8.1 MHz however creating all this took time and discussion and signals wouldn't begin broadcasting until December 1988 the initial aspect ratio for this High Vision system was 2 to one at around the same time Sony released this this is the HDM 3830 color monitor and it's a beast this CRT not only has a 38 in visible picture but it can take a 1080i input yep you could plug a PS5 into this thing and play until your heart's content it also has a 16x9 aspect ratio that okay let's just stop there a second I've covered aspect ratios but this TV could take 1080i in 1988 that's crazy right well yes and no in 1974 work on the cciir study program for highdef television had led to a number of groups and other International initiatives one of which was that in March 1977 the Society of motion picture and television engineers in America had begun development of a digital television interface standard By 1979 a standard had been draft that allowed the ntsc television signal to be sampled as a single composite color signal over in Europe the European broadcasting Union issued a document at around the same time recommending a component television production standard and it was quickly realized that the community would be best served by a single set of standards that could be applied to ntsc pal and ccam by January 1980 as SM pte task force was set up to ensure compatibility across all systems of course to do that we need to take our analog signals and convert them now remember our television lines number well this needed to be sampled to make it digital this sampling rate is known as the number of samples per active line and how many samples we take depends on the signal sampling frequency for example as signal sampled at 6.75 MHz would give 360 samples per active line a signal sampled at Double that rate would give double the samples per line at this point of negotiations the stipulations were that the European Community wanted a luminant signal sampling frequency lower than 14. 318 MHz whilst America wanted more than 12 MHz to accommodate All European standards for active line periods it was further put forward that the number of samples per line should be greater than 7155 with 720 being 6 factorial allowing for many small factors it seemed the ideal number this is much higher than the tvl numbers I mentioned earlier but remember tvl doesn't relate to how much data there is it's simply what is discernable on screen and really shows how much of image was lost due to analog transmission bandwidth and TV receivers mats in part why a DVD image looks so much clearer than an analog image of the same Source material so in the business of converting an analog signal to digital we're pulling a defined number of horizontal samples which is then normalized to our number of scan lines so as to retain the 4x3 image format it was therefore suggested that a 3 * 4.5 MHz sampling frequency should be used equating to 13.5 MHz this makes sense as both ntsc and power line frequencies can be synchronized to 4.5 MHz and therefore any multiple thereof it was this frequency which delivered 720 samples per active line accommodating the needs of both European and American systems and allowing our TV lines to be defined in acceptable digital Clarity by February 1981 this component Recording Technology was effectively born with the EB demonstrating component coded systems in January 1981 to the international broadcasting Authority followed by the Bureau of the technical Committee in San Francisco a month later these demonstrations were supported by companies including ABC television CBS RCA Laboratories and Sony Corporation by Autumn 1981 NHK in Japan the Ebu in Europe and the SM smpte in America had agreed on the 13.5 mahz 422 component digital recording standard by 1982 this had been put forward in SM smpte 125 and itu recommendation 601 which defined how to encode interlace analog video signals into digital video form it also recommended that the horizontal resolution for HD TV should be twice that of conventional television systems if you take 720 samples per active line that gives us a horizontal sample rate or resolution of 1440 fast forward a few years to 1984 and a gentleman by the name of KS H Powers was working on the problem of standardizing the image formats used in our homes and in our Cinemas ultimately he laid out all the main existing film and broadcasting ratios in front of him overlapping their Center points to give us the aspect ratio of 16 to 9 now expanding a 4x3 screen out to 16x9 requires one third more samples than a 4x3 picture ratio so if we take our 14 of 40 and adjust the count for 16x9 ratio we get 1,920 samples per active line yeah things are starting to take shape literally in 1987 the itu was still not entirely convinced and were faffing about with screen ratios having defined the following parameters for their first HD TV recommendation active lines 1152 field rate 50 HZ scanning method Progressive aspect ratio 19 by9 samples per line 1920 for luminance so when Sony released for HDM 3830 they were pretty much taking a punt based on the SM smpte work the technology for component connections had been finalized but globally highdef TV had not completely been defined nor digital Japan was pushing out its experimental high Vision HDTV system which delivered 1,35 lines of visible screen data with 1,920 samples per line but there was no guarantee this would stick around the fact that this thing can take 1080i signals is really Testament to the work that the itu and SM smpte had done on standardization it wouldn't be until 1990 a 17th CCI our plary assembly that the itu recommendation 709 was approved which defined the picture ratio of 16x9 along with our 1,920 samples per active line however at this stage the total number of agreed vertical lines still varied to allow for international variations something worth considering at this point is that neither NTC nor pal pixels are square if you digitize our analog signal and take the s horizontal width plac F against our line height you don't get a square ntsc pixels are narrower than they are high allowing for the 720x 486 aspect ratio whilst pal pixels are wider than they are high allowing for the 720x 576 aspect ratio it's what allows both formats to be different ratios of themselves but yet fit in the same aspect screen ratio it's here where we jump back to the Computing Comm Community who had one wish well I imagine they had hundreds but in terms of pixels they wanted one thing Square pixels and that's because computers well they already used square pixels your average PC display in the state was the same as your average PC display in the UK no fuss just perfection which allowed our fabulous resolutions to exist in Harmony and abundance it's also because editing ntsc and Power video in a PC without standard pixel sizes is a menace so if you take our 1920 samples per line and convert them into the world of PCS you effectively get 1920 pixels if you work out how many square pixels you then need to fill the vertical space of a 16x9 screen you get 1080 Bingo 1 920 by 1080 our HD resolution is born and although it wasn't Common Place place anywhere yet it made sense from a manufacturer's point of view and it made sense from a standardization point of view especially when you consider that the LCD screens about to hit the market had a defined number of physical pixels as opposed to be more versatile whims of a CRT meaning that a pixel in your computer's memory can actually equate to a physical pixel on screen it wouldn't be until the year 2000 that recommendation itu bt79 was approved that said our HD resolution and our screen ratio allowing manufacturers to produce equipment at a lower cost and for broadcasters to work towards common HDTV program production standards our 720p screens also followed the same rule 720 horizontal pixels time 4/3 resolution Improvement adjusted for 16x9 equated to 1280x 720 offering a coste effective step into the world of full HD and a noticeable Step Up in quality from the standard resolution video as for 1080i well again it worked as a stop Gap and did the whole interlace thing that our standards had been used to up until this point but Progressive scanning was always the future it would take about 10 years for HD 16x9 displays to be adopted universally by both the Computing world and the TV World PC owners went through a variety of resolutions between B Millennium and 2010 with 1024x 768 being the most common at the dawn before an abundance of 5x4 LCD screens made 1280 x 1024 more popular followed by 1440 by 900 on 16 by 10 displays which were more prevalent until economies of scale meant that standardization between the computer screens and TVs made much more sense ultimately it also allowed graphics cards and their cost to catch up to to a point where a 1920x 1080 desktop and gaming resolution made much more sense but it will always be strange to me that although computer resolutions led the way for so long it would be the weird cumbersome and desperate world of Television broadcasting But ultimately took the lead and steered us on it may have taken 70 years but standardization finally came just about everything else that came after 4K 8K well it's all born from this original HD standard until next time I've been Nostalgia nered to Lo [Music]

Channel: Nostalgia Nerd

Views: 213,878

Keywords: hd video, 1080p

Id: loiha3kRsoY

Length: 20min 58sec (1258 seconds)

Published: Thu Jun 27 2024