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120-577: The October 2015 basic draft requirements for NETVC were support for a bit depth of 8-bits to 10-bits per sample, 4:2:0 chroma subsampling , 4:4:4 YUV , low coding delay capability, feasible real time decoder/encoder software implementations, temporal scalability, and error resilience tools. The October 2015 optional draft requirements for NETVC included support for a bit depth of up to 16-bits per sample, 4:2:2 chroma subsampling, RGB video, auxiliary channel planes, high dynamic range , and parallel processing tools. On March 24, 2015, Xiph.org 's Daala codec

240-712: A "blaze of publicity" at the Earl's Court Computer Show in London, and the ZX Microfair in Manchester . The ZX Spectrum was launched with two models: a 16KB 'basic' version, and an enhanced 48KB variant. The former model had an undercutting price of £125, significantly lower than its main competitor the BBC Micro , whilst the latter model's price of £175 was comparable to a third of an Apple II computer. Upon release,

360-455: A 4-level alpha channel ); the Cineon file format , for example, used this. Some SGI systems had 10- (or more) bit digital-to-analog converters for the video signal and could be set up to interpret data stored this way for display. BMP files define this as one of its formats, and it is called "HiColor" by Microsoft . Video cards with 10 bits per component started coming to market in

480-424: A Briton taking on the world, Sinclair has become the best-known name in micros." The media latched onto Sinclair's image; his "Uncle Clive" persona is said to have been created by the gossip columnist for Personal Computer World . The press praised Sinclair as a visionary genius, with The Sun lauding him as "the most prodigious inventor since Leonardo da Vinci ". Adamson and Kennedy wrote that Sinclair outgrew

600-462: A bit depth of 8 bits to 16 bits per sample. As of 2020, some smartphones have started using 30-bit color depth, such as the OnePlus ;8 Pro , Oppo Find X2 & Find X2 Pro, Sony Xperia 1 II , Xiaomi Mi 10 Ultra , Motorola Edge+ , ROG Phone 3 and Sharp Aquos Zero 2. Using 12 bits per color channel produces 36 bits, 68,719,476,736 colors. If an alpha channel of

720-552: A color channel is also known as radiometric resolution , especially in the context of satellite images . With the relatively low color depth, the stored value is typically a number representing the index into a color map or palette (a form of vector quantization ). The colors available in the palette itself may be fixed by the hardware or modifiable by software. Modifiable palettes are sometimes referred to as pseudocolor palettes. Old graphics chips, particularly those used in home computers and video game consoles , often have

840-412: A color cube in the palette for a direct-color system (and so all programs would use the same palette). Usually fewer levels of blue were provided than others, since the normal human eye is less sensitive to the blue component than to either red or green (two thirds of the eye's receptors process the longer wavelengths ). Popular sizes were: 4,096 colors, usually from a fully-programmable palette (though it

960-516: A command in BASIC, many keywords require a single keyboard stroke. Other keywords require a change of keyboard mode by a few keystrokes. The BASIC interpreter is derived from the one used on the ZX81 . A BASIC program for ZX81 can be entered into a ZX Spectrum with minimal modifications. However, Spectrum BASIC introduced numerous additional features, enhancing its usability. The ZX Spectrum character set

1080-505: A contemporary laser printer) but color proved more popular. 4 colors, usually from a selection of fixed palettes. Gray-scale early NeXTstation , color Macintoshes, Atari ST medium resolution. 8 colors, almost always all combinations of full-intensity red, green, and blue. Many early home computers with TV displays, including the ZX Spectrum and BBC Micro . 16 colors, usually from a selection of fixed palettes. Used by IBM CGA (at

1200-511: A custom interpreter made it possible to fit all of its functionality into a very small amount of read-only memory (ROM). The development process of the software was marked by disagreements between Nine Tiles and Sinclair Research. Sinclair placed an emphasis on expediting the release of the Spectrum, primarily by minimising alterations in the software from the ZX81, which had in turn been based on

1320-457: A full range of colour and sound for a price under $ 200. Although it was more enhanced than its British counterpart, sales proved poor and Timex Sinclair collapsed the following year. A crucial part of the company's marketing strategy was to implement regular price-cutting at strategic intervals to maintain market share . Ian Adamson and Richard Kennedy noted that Sinclair's method was driven by securing his leading position through "panicking"

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1440-458: A fully hardware-based television raster generator with colour support. This enhancement indirectly provided the new machine with roughly four times the processing power of the ZX81, as the Z80 was relieved of video generation tasks. An initial ULA design flaw occasionally led to incorrect keyboard scanning, which was resolved by adding a small circuit board mounted upside down ("dead cockroach") next to

1560-603: A high of 40 per cent. Sales in the 1984 Christmas season were described as "extremely good". In early 1985 the British press reported the home computer boom to have ended, leaving many companies slashing prices of their hardware to anticipate lower sales. Despite this, celebration of Sinclair's success in the computing market continued at the Which Computer? show in Birmingham , where the five-millionth ZX Spectrum

1680-694: A lacking distribution. Nigel Searle , the newly-appointed chief of Sinclair's computer division, said in June 1982 the company had no plans to stock the new machine in WHSmith , which was at the time Sinclair's only retailer. Searle explained that the mail-order system was in place due to there being no "obvious" retail outlets in the United Kingdom which could sell personal computers, and it made "better sense" financially to continue selling through mail-order. The company's conservative approach to distributing

1800-697: A non-textured surface were at risk of causing shock, and were asked to be sent back to a warehouse in Cambridgeshire which would supply a replacement within 48 hours. Development of the ZX Spectrum+ began in June 1984, and was released on 15 October that year at £179. It was assembled by AB Electronics in South Wales and Samsung in South Korea. This 48 KB Spectrum introduced a new QL -style case with an injection-moulded keyboard and

1920-517: A reset button that functions as a switch shorting across the CPU reset capacitor. Electronically, it was identical to the previous 48 KB model. The machine outsold the rubber-key model two to one, however, some retailers reported a failure rate of up to 30%, compared with a more typical 5–6% for the older model. In early 1985, the original Spectrum was officially discontinued, and the ZX Spectrum+

2040-662: A significant commercial failure, selling only 17,000 units and losing Sinclair £7 million. It has since been described as "one of the great marketing bombs of postwar British industry". The ASA ordered Sinclair to withdraw advertisements for the C5 after finding that the company's claims about its safety could not be proved or justified. The combined failures of the C5 and QL caused investors to lose confidence in Sinclair's judgement. In May 1985, Sinclair Research announced their intention to raise an additional £10 to £15 million to restructure

2160-735: A significant drop in Sinclair's income from orders in January, as retailers were left with surplus stock. Subsequently, an upgraded model, the ZX Spectrum 128, was released in Spain in September 1985, with development financed by the Spanish distributor Investrónica. The launch of this model in the UK was postponed until January 1986 due to the substantial leftover inventory of the prior model. While

2280-552: A single chip, the essential hardware functions. Altwasser designed a graphics mode that required less than 7 kilobytes of memory and implemented it on the ULA. Vickers wrote most of the ROM code. Lengthy discussions between Altwasser and Sinclair engineers resulted in a broad agreement that the ZX Spectrum must have high-resolution graphics, 16 kilobytes of memory, an improved cassette interface , and an impressive colour palette. To achieve this,

2400-517: A small office at 6 King's Parade , Cambridge. During early production, the machine was known as the ZX81 Colour or the ZX82 to highlight the machine's colour display, which differed from the black and white of its predecessors. The addendum "Spectrum" was added later on, to emphasise its 15-colour palette. Aside from a new crystal oscillator and extra chips to add additional kilobytes of memory,

2520-465: A television speaker. The ZX Spectrum +2 marked Amstrad's entry into the Spectrum market shortly after their acquisition of the Spectrum range and "Sinclair" brand in 1986. This machine featured a brand-new grey case with a spring-loaded keyboard, dual joystick ports, and an integrated cassette recorder known as the "Datacorder," akin to the Amstrad CPC 464 . However, it was largely identical to

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2640-649: A time, was governed by the BASIC command 'BEEP', where programmers could manipulate parameters for pitch and duration. Furthermore, the processor remained occupied exclusively with the BASIC BEEPs until their completion, limiting concurrent operations. Despite these constraints, it marked a significant step forward from the ZX81 , which lacked any sound capabilities. Resourceful programmers swiftly devised workarounds; its rudimentary audio functionality compelled developers to explore unconventional methods such as programming

2760-455: A visually lossless low-latency algorithm based on predictive DPCM and YCoCg-R color space and allows increased resolutions and color depths and reduced power consumption." At WinHEC 2008, Microsoft announced that color depths of 30 bits and 48 bits would be supported in Windows 7 , along with the wide color gamut scRGB . High Efficiency Video Coding (HEVC or H.265) defines

2880-413: A yellow subpixel. However, formats and media that allow or make use of the extended color gamut are at present extremely rare. Because humans are overwhelmingly trichromats or dichromats one might suppose that adding a fourth "primary" color could provide no practical benefit. However humans can see a broader range of colors than a mixture of three colored lights can display. The deficit of colors

3000-551: A £7 million investment loss, Sinclair was given a golden handshake and an estimated £10,000 severance package. He had a former employee, Christopher Curry , establish a "corporate lifeboat" company named Science of Cambridge Ltd, in July 1977, called such as they were located near the University of Cambridge . By this time inexpensive microprocessors had started appearing on the market, which prompted Sinclair to start producing

3120-409: Is a Zilog Z80 , an 8-bit microprocessor , with a clock rate of 3.5  MHz . The original model Spectrum has 16 KB of ROM and either 16 kB or 48 kB of RAM. Video output is channelled through an RF modulator , intended for use with contemporary television sets, to provide a simple colour graphic display. Text is displayed using a grid of 32 columns × 24 rows of characters from

3240-414: Is also often used to refer to all color depths greater or equal to 24. Deep color consists of a billion or more colors. 2 is 1,073,741,824. Usually this is 10 bits each of red, green, and blue (10 bpc). If an alpha channel of the same size is added then each pixel takes 40 bits. Some earlier systems placed three 10-bit channels in a 32-bit word , with 2 bits unused (or used as

3360-554: Is assigned 5 bits, plus one unused bit (or used for a mask channel or to switch to indexed color); this allows 32,768 colors to be represented. However, an alternate assignment which reassigns the unused bit to the G channel allows 65,536 colors to be represented, but without transparency. These color depths are sometimes used in small devices with a color display, such as mobile phones, and are sometimes considered sufficient to display photographic images. Occasionally 4 bits per color are used plus 4 bits for alpha, giving 4,096 colors. Among

3480-614: Is either the number of bits used to indicate the color of a single pixel , or the number of bits used for each color component of a single pixel. When referring to a pixel, the concept can be defined as bits per pixel (bpp). When referring to a color component, the concept can be defined as bits per component , bits per channel , bits per color (all three abbreviated bpc), and also bits per pixel component , bits per color channel or bits per sample (bps). Modern standards tend to use bits per component, but historical lower-depth systems used bits per pixel more often. Color depth

3600-421: Is only one aspect of color representation, expressing the precision with which the amount of each primary can be expressed; the other aspect is how broad a range of colors can be expressed (the gamut ). The definition of both color precision and gamut is accomplished with a color encoding specification which assigns a digital code value to a location in a color space . The number of bits of resolved intensity in

3720-408: Is particularly noticeable in saturated shades of bluish green (shown as the left upper grey part of the horseshoe in the diagram) of RGB displays: Most humans can see more vivid blue-greens than any color video screen can display. ZX Spectrum The ZX Spectrum ( UK : / z ɛ d ɛ k s / ) is an 8-bit home computer developed and marketed by Sinclair Research . Considered one of

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3840-535: Is significantly more advanced than the ZX81, with approximately four times faster average speeds. The original ZX Spectrum is remembered for its rubber chiclet keyboard , diminutive size and distinctive rainbow motif. It was originally released on 23 April 1982 with 16 KB of RAM for £125 (equivalent to £557 in 2023) or with 48 KB for £175 (equivalent to £780 in 2023); these prices were reduced to £99 (equivalent to £422 in 2023) and £129 (equivalent to £550 in 2023) respectively in 1983. Owners of

3960-606: Is transmitted to a television set rather than a dedicated monitor , while application software is loaded and saved onto compact audio cassettes . The ZX Spectrum was initially distributed by mail order, but after severe backlogs it was sold through High Street chains in the United Kingdom. It was released in the US as the Timex Sinclair 2068 in 1983, and in some parts of Europe as the Timex Computer 2048 . Ultimately

4080-527: Is used by virtually every computer and phone display and the vast majority of image storage formats . Almost all cases of 32 bits per pixel assigns 24 bits to the color, and the remaining 8 are the alpha channel or unused. 2 gives 16,777,216 color variations. The human eye can discriminate up to ten million colors, and since the gamut of a display is smaller than the range of human vision, this means this should cover that range with more detail than can be perceived. However, displays do not evenly distribute

4200-445: The MIC port is intended for attachment to other audio devices as a line-in source. The ZX Spectrum integrated various design elements from the ZX81. The keyboard decoding and cassette interfaces were nearly identical, although the latter was programmed for higher-speed loading and saving. The central ULA integrated circuit shares some resemblance with that of the ZX81, but it features

4320-578: The AY-3-8912 chip, MIDI compatibility, an RS-232 serial port, an RGB monitor port, 32 KB of ROM including an improved BASIC editor, and an external keypad. The machine was simultaneously unveiled for the first time and launched in September 1985 at the SIMO '85 trade show in Spain, with a price of 44,250 pesetas . Sinclair later presented the ZX Spectrum 128 at The May Fair Hotel 's Crystal Rooms in London, where he acknowledged that entertainment

4440-592: The Advertising Standards Authority (ASA) in May of that year. Particularly serious were allegations that Sinclair was cashing cheques months before machines were shipped. By autumn 1984, Sinclair was still publicly forecasting that it would be a "million seller" and that 250,000 units would be sold by the end of the year. QL production was suspended in February 1985, and the price was halved by

4560-484: The MK14 , a computer teaching kit which sold well at a very low price. Encouraged by this success, Sinclair renamed his company to Sinclair Research , and started looking to manufacture personal computers. Keeping the cost low was essential for Sinclair to avoid his products from becoming outpriced by American or Japanese equivalents as had happened to several of the previous Sinclair Radionics products. On 29 January 1980,

4680-773: The Nvidia Quadro graphics cards manufactured after 2006 support 30-bit deep color and Pascal or later GeForce and Titan cards when paired with the Studio Driver as do some models of the Radeon HD ;5900 series such as the HD ;5970. The ATI FireGL V7350 graphics card supports 40- and 64-bit pixels (30 and 48 bit color depth with an alpha channel). The DisplayPort specification also supports color depths greater than 24 bpp in version 1.3 through " VESA Display Stream Compression , which uses

4800-412: The ZX Spectrum character set , or from a custom set. The machine features a colour palette of 15 colours, consisting of seven saturated colours at two levels of brightness, along with black. The image resolution is 256×192 pixels, subject to the same colour limitations. To optimise memory usage, colour is stored separately from the pixel bitmap in a low resolution, 32×24 grid overlay, corresponding to

4920-581: The ZX80 home computer was launched to immediate popularity; notable for being one of the first computers available in the United Kingdom for less than £100. The company conducted no market research whatsoever prior to the launch of the ZX80; according to Sinclair, he "simply had a hunch" that the public was sufficiently interested to make such a project feasible and went ahead with ordering 100,000 sets of parts so that he could launch at high volume. On 5 March 1981,

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5040-658: The ZX81 was launched worldwide to immense success with more than 1.5 million units sold, 60% of which was outside Britain. According to Ben Rosen , by pricing the ZX81 so low, the company had "opened up a completely new market among people who had never previously considered owning a computer". After its release, computing in Britain became an activity for the general public rather than the preserve of office workers and hobbyists. The ZX81's commercial success made Sinclair Research one of Britain's leading computer manufacturers, with Sinclair himself reportedly "amused and gratified" by

5160-488: The color gamut of a display, since it is no longer limited to the interior of a triangle formed by three primaries at its corners, e.g. the CIE 1931 color space . Recent technologies such as Texas Instruments 's BrilliantColor augment the typical red, green, and blue channels with up to three other primaries: cyan, magenta, and yellow. Cyan would be indicated by negative values in the red channel, magenta by negative values in

5280-436: The open standard image file format OpenEXR which supported 16-bit-per-channel half-precision floating-point numbers. At values near 1.0, half precision floating point values have only the precision of an 11-bit integer value, leading some graphics professionals to reject half-precision in situations where the extended dynamic range is not needed. Virtually all television displays and computer displays form images by varying

5400-469: The 16 KB model could purchase an internal 32 KB RAM upgrade, which for early "Issue 1" machines consisted of a daughterboard . Later issue machines required the fitting of 8 dynamic RAM chips and a few TTL chips. Users could mail their 16K Spectrums to Sinclair to be upgraded to 48 KB versions. Later revisions contained 64 KB of memory but were configured such that only 48 KB were usable. External 32 KB RAM packs that mounted in

5520-458: The British information technology industry. The Spectrum is one of the best-selling British computers of all time, retaining the title of Britain's top-selling computer until the Amstrad PCW surpassed it in the 1990s. It was discontinued in 1992. The ZX Spectrum was conceived and designed by engineers at Sinclair Research, founded by English entrepreneur and inventor Clive Sinclair , who

5640-534: The CPU in Issue 1 ZX Spectrums. The machine's Sinclair BASIC interpreter is stored in 16 KiB ROM, along with essential system routines. The ROM code, responsible for tasks such as floating point calculations and expression parsing , exhibited significant similarities to ZX81, although a few outdated routines remained in the Spectrum ROM. The Spectrum's keyboard is imprinted with BASIC keywords. To input

5760-462: The Commodore 64 also employed colour attributes, it utilised a special multicolour mode and hardware sprites to circumvent attribute clash. Sound output is produced through a built-in beeper capable of generating a single channel with ten octaves. It is controlled by a single EAR bit. By toggling it on and off, simple sounds are generated. This speaker, capable of producing just one note at

5880-664: The Main ;10 profile, which allows for 8 or 10 bits per sample with 4:2:0 chroma subsampling . The Main 10 profile was added at the October ;2012 HEVC meeting based on proposal JCTVC-K0109 which proposed that a 10-bit profile be added to HEVC for consumer applications. The proposal stated that this was to allow for improved video quality and to support the Rec. 2020 color space that will be used by UHDTV . The second version of HEVC has five profiles that allow for

6000-565: The ROM were also eliminated, rendering some older 48K and 128K games incompatible with the machine. The ZX Interface 1 was also rendered incompatible due to disparities in ROM and expansion connectors, making it impossible to connect and use the Microdrive units. Production of the +3 was discontinued in December 1990, reportedly in response to Amstrad's relaunch of their CPC range, with an estimated 15% of ZX Spectrums sold being +3 models at

6120-526: The Sinclair QL was in development, Sinclair also hoped to repeat his success with the Spectrum in the fledgling electric vehicle market, which he saw as ripe for a new approach. On 10 January 1985, Sinclair unveiled the Sinclair C5 , a small one-person battery electric recumbent tricycle . It marked the culmination of Sir Clive's long-running interest in electric vehicles. The C5 turned out to be

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6240-472: The Spanish alphabet and show messages in Spanish. The appearance of the ZX Spectrum 128 is similar to the ZX Spectrum+, with the exception of a large external heatsink for the internal 7805 voltage regulator added to the right hand end of the case, replacing the internal heatsink in previous versions. This external heatsink led to the system's nickname, "The Toast Rack ". New features included 128 KB RAM with RAM disc commands, three-channel audio via

6360-603: The Spectrum was released as seven different models, ranging from the entry level with 16  KB RAM released in 1982 to the ZX ;Spectrum +3 with 128 KB RAM and built-in floppy disk drive in 1987. Throughout its life, the machine primarily competed with the Commodore ;64 , BBC Micro , Dragon 32 , and the Amstrad ;CPC range. Over 24,000 different software products were released for

6480-422: The Spectrum's rubber keyboard was simplified from several hundred components to a conventional moving keyboard down to "four to five" moving parts using a new technology. The keyboard was still undergoing changes as late as February 1982; some sketches included a roundel-on-square key design which was later featured on the later Spectrum+ model. Dickinson recalled in 2007 that "everything was cost driven" and that

6600-520: The ZX Spectrum +3 power supply utilised a DIN connector and featured "Sinclair +3" branding on the case. Significant alterations caused a series of incompatibilities, such as the removal of several lines on the expansion bus edge connector. This resulted in complications for various peripheries. Additionally, changes in memory timing led to certain RAM banks being contended, causing failures in high-speed colour-changing effects. The keypad scanning routines from

6720-625: The ZX Spectrum 128 in most technical aspects. The machine retailed for £149. The new keyboard did not feature the BASIC keyword markings seen on earlier Spectrums, except for the keywords LOAD , CODE , and RUN , which were useful for loading software. Instead, the +2 introduced a menu system, almost identical to that of the ZX Spectrum 128, allowing users to switch between 48K BASIC programming with keywords and 128K BASIC programming, where all words, both keywords and others, needed to be typed out in full (though keywords were still stored internally as one character each). Despite these changes,

6840-482: The ZX Spectrum was intended to be, as quoted by Sinclair's marketing manager, essentially a "ZX81 with colour". According to Sinclair, the team also wanted to combine the ZX81's separate random-access memory sections for audio and video into a single bank. Chief engineer Richard Altwasser was responsible for the ZX Spectrum's hardware design. His main contribution was the design of the semi-custom uncommitted logic array (ULA) integrated circuit, which integrated, on

6960-413: The ZX Spectrum. The Spectrum played a pivotal role in the early history of personal computing and video gaming , leaving an enduring legacy that influenced generations. Its introduction led to a boom in companies producing software and hardware , the effects of which are still seen. It was among the first home computers aimed at a mainstream audience, with some crediting it as responsible for launching

7080-529: The ZX80's software. The software architecture of the ZX80, however, had been tailored for a severely constrained memory system, and in Nine Tiles' opinion was unsuitable for the enhanced processing demands of the ZX Spectrum. Sinclair favoured solving this with expansion modules on the existing framework like with the ZX81, which Nine Tiles disagreed with. Ultimately, both designs were developed, but Vickers and Nine Tiles were unable to finish their version before

7200-444: The ability to use a different palette per sprites and tiles in order to increase the maximum number of simultaneously displayed colors, while minimizing use of then-expensive memory (and bandwidth). For example, in the ZX Spectrum the picture is stored in a two-color format, but these two colors can be separately defined for each rectangular block of 8×8 pixels. The palette itself has a color depth (number of bits per entry). While

7320-407: The attention the machine received. Development of the ZX Spectrum began in September 1981, a few months after the release of the ZX81. Sinclair resolved to make his own products obsolete before his rivals developed the products that would do so. Parts of designs from the ZX80 and ZX81 were reused to ensure a speedy and cost-effective manufacturing process. The team consisted of 20 engineers housed in

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7440-399: The beeper to emit multiple pitches. Later software became available that allowed for two-channel sound playback. The machine includes an expansion bus edge connector and 3.5 mm audio in/out ports, facilitating the connection of a cassette recorder for loading and saving programs and data. The EAR port has a higher output than the MIC and is recommended for headphones, while

7560-443: The best VGA systems only offered an 18-bit (262,144 color) palette from which colors could be chosen, all color Macintosh video hardware offered a 24-bit (16 million color) palette. 24-bit palettes are nearly universal on any recent hardware or file format using them. If instead the color can be directly figured out from the pixel values, it is "direct color". Palettes were rarely used for depths greater than 12 bits per pixel, as

7680-413: The bottom 2 bits of 8-bit data, but if 16 bits were used it would lose none of the 8-bit data). In addition, digital cameras are able to produce 10 or 12 bits per channel in their raw data; as 16 bits is the smallest addressable unit larger than that, using it would make it easier to manipulate the raw data. Some systems started using those bits for numbers outside the 0–1 range rather than for increasing

7800-414: The case was to be more angular and wedge-like, in similar vein to an upgraded ZX81 model. Dickinson later settled on a flatter design with a raised rear section and rounded sides in order to depict the machine as "more advanced" as opposed to a mere upgrade. In drawing up potential logos, Dickinson proposed a series of different logotypes which all featured rainbow slashes across the keyboard. The design of

7920-422: The character cells. In practical terms, this means that all pixels within an 8x8 character block share one foreground colour and one background colour. Altwasser received a patent for this design. An "attribute" consists of a foreground and a background colour, a brightness level (normal or bright) and a flashing "flag" which, when set, causes the two colours to swap at regular intervals. This scheme leads to what

8040-400: The colors in human perception space, so humans can see the changes between some adjacent colors as color banding . Monochromatic images set all three channels to the same value, resulting in only 256 different colors; some software attempts to dither the gray level into the color channels to increase this, although in modern software this is more often used for subpixel rendering to increase

8160-551: The company sold their entire computer product range, along with the "Sinclair" brand name, to Alan Sugar 's Amstrad for £5 million. The takeover sent ripples through the London Stock Exchange , but Amstrad's shares soon recovered, with one stock broker affirming that " the City appears to have taken the news in its stride". Amstrad's acquisition of the brand name saw the release of three ZX Spectrum models throughout

8280-408: The company's Dryburgh factory. Prior to the manufacture of the ZX81, however, Timex had little experience in assembling electronics and had not originally been an obvious choice of manufacturing subcontractor. It was a well-established manufacturer of mechanical watches but was facing a crisis at the beginning of the 1980s; profits had dwindled to virtually zero as the market for watches stagnated in

8400-411: The company. Clive Sinclair became a focal point during the ZX Spectrum's marketing campaign by putting a human face onto the business. Sinclair Research was portrayed in the media as a "plucky" British challenger taking on the technical and marketing might of giant American and Japanese corporations. As David O'Reilly noted in 1986, "by astute use of public relations, particularly playing up his image of

8520-468: The competition. While most companies at the time reduced prices of their products while their market share was dwindling, Sinclair Research discounted theirs shortly after sales had peaked, throwing the competition into "utter disarray". Sinclair Research made a profit of £14 million in 1983, compared to £8.5 million the previous year. Turnover doubled from £27.2 million to £54.5 million, which equated to roughly £1 million for each person employed directly by

8640-404: The data transfer speed, the team significantly decreased the length of tones that represent binary data. To increase the reliability, a leading period of constant tone was introduced, which allowed the cassette recorder's automatic gain control to settle itself down, eliminating hisses on the tape. A Schmitt trigger was added inside the ULA to reduce noise of the received signal. Originally,

8760-428: The end of that month. Supply did not return to normal until the 1982 Christmas season, however. Production of the machine rapidly increased with the arrival of the more inexpensive Issue 2 motherboard , a redesign of the main circuit board which addressed hardware manufacturing defects that affected production of the first model. Sales of the ZX Spectrum reached 200,000 in its first nine months, rising to 300,000 for

8880-623: The end of the year. It ultimately flopped, with 139,454 units being manufactured. The ZX Spectrum+, a rebranded ZX Spectrum with identical technical specifications except for the QL-like keyboard, was introduced in October 1984 and made available in WHSmith's stores the day after its launch. Retailers stocked the device in high quantities, anticipating robust Christmas sales. Nevertheless, the product did not perform as well as projected, leading to

9000-540: The face of competition from the digital and quartz watches . Recognising the trend, Timex's director, Fred Olsen , determined that the company would diversify into other areas and signed a contract with Sinclair. The ZX Spectrum was officially revealed before journalists by Sinclair at the Churchill Hotel in Marylebone , London, on 23 April 1982. Later that week, the machine was officially presented in

9120-769: The first hardware to use the standard were the Sharp X68000 and IBM's Extended Graphics Array (XGA). The term "high color" has recently been used to mean color depths greater than 24 bits. Almost all of the least expensive LCDs (such as typical twisted nematic types) provide 18-bit color (64×64×64 = 262,144 combinations) to achieve faster color transition times, and use either dithering or frame rate control to approximate 24-bit-per-pixel true color, or throw away 6 bits of color information entirely. More expensive LCDs (typically IPS ) can display 24-bit color depth or greater. 24 bits almost always use 8 bits each of R, G, and B (8 bpc). As of 2018, 24-bit color depth

9240-582: The fraction. The Cineon imaging system used 10-bit professional video displays with the video hardware adjusted so that a value of 95 was black and 685 was white. The amplified signal tended to reduce the lifetime of the CRT. More bits also encouraged the storage of light as linear values, where the number directly corresponds to the amount of light emitted. Linear levels makes calculation of computer graphics much easier. However, linear color results in disproportionately more samples near white and fewer near black, so

9360-414: The green channel, and yellow by negative values in the blue channel, validating the use of otherwise fictitious negative numbers in the color channels. Mitsubishi and Samsung (among others) use BrilliantColor in some of their TV sets to extend the range of displayable colors. The Sharp Aquos line of televisions has introduced Quattron technology, which augments the usual RGB pixel components with

9480-585: The ill-fated digital Black Watch wristwatch. Due to financial losses, Sinclair sought investors from the National Enterprise Board (NEB), who had bought a 43% interest in the company and streamlined his product line. Sinclair's relationship with the NEB had worsened, however, and by 1979 it opted to break up Sinclair Radionics entirely, selling off its television division to Binatone and its calculator division to ESL Bristol. After incurring

9600-428: The keyboard surprised many users due to its use of rubber keys, described as offering the feel of "dead flesh". Sinclair himself remarked that the keyboard's rubber mould was "unusual", but consumers were undeterred. Despite very high demand, Sinclair Research was "notoriously late" in delivering the ZX Spectrum. Their practice of offering mail-order sales before units were ready ensured a constant cash flow, but meant

9720-433: The late 1980s, each with varying improvements. By 1990, Sinclair Research consisted of Sinclair and two other employees down from 130 employees at its peak in 1985. The ZX Spectrum was officially discontinued in 1992, after ten years on the market. Sinclair Research thereafter continued to exist as a one-man company, marketing Sir Clive Sinclair's inventions until his death in September 2021. The central processing unit

9840-604: The late 1990s. An early example was the Radius ThunderPower card for the Macintosh, which included extensions for QuickDraw and Adobe Photoshop plugins to support editing 30-bit images. Some vendors call their 24-bit color depth with FRC panels 30-bit panels; however, true deep color displays have 10-bit or more color depth without FRC. The HDMI  1.3 specification defines a bit depth of 30 bits (as well as 36 and 48 bit depths). In that regard,

9960-443: The launch of the Spectrum and it was not used. The distinctive case and colourful design of the ZX Spectrum was the creation of Rick Dickinson , a young British industrial designer who had been hired by Sinclair to design the ZX81. Dickinson was tasked to design a sleeker and more "marketable" appearance to the new machine, whilst ensuring all 192 BASIC functions could fit onto 40 physical keys. Early sketches from August 1981 showed

10080-462: The layout remained identical to that of the 128. The ZX Spectrum +3 , which was launched in 1987, bore a resemblance to its predecessor but introduced a built-in 3-inch floppy disk drive instead of the cassette drive. Initially priced at £249, it later retailed for £199. It was the only Spectrum model capable of running the CP/M operating system without additional hardware. Unlike its predecessors,

10200-600: The lowest resolution), EGA , and by the least common denominator VGA standard at higher resolution. Color Macintoshes, Atari ST low resolution, Commodore 64 , and Amstrad CPCs also supported 4-bit color. 32 colors from a programmable palette, used by the Original Amiga chipset . 64 colors. Used by the Master System , Enhanced Graphics Adapter, GIME for TRS-80 Color Computer 3, Pebble Time smartwatch (64 color e-paper display), and Parallax Propeller using

10320-500: The machine into 48K mode, keeping the current BASIC program intact (although there is no command to switch back to 128K mode). To enable BASIC programmers to access the additional memory, a RAM disk was created where files could be stored in the additional 80 KB of RAM. The new commands took the place of two existing user-defined-character spaces causing compatibility problems with certain BASIC programs. Unlike its predecessors, it has no internal speaker, and can only produce sound from

10440-469: The machine was criticised, with disillusioned customers telephoning and writing letters. Demand sky-rocketed beyond Sinclair's planned 20,000 monthly unit output to a backlog of 30,000 orders by July 1982. Due to a scheduled holiday at the Timex factory that summer, the backlog had risen to 40,000 units. Sinclair issued a public apology in September that year, and promised that the backlog would be cleared by

10560-472: The memory consumed by the palette would exceed the necessary memory for direct color on every pixel. 2 colors, often black and white direct color. Sometimes 1 meant black and 0 meant white, the inverse of modern standards. Most of the first graphics displays were of this type, the X Window System was developed for such displays, and this was assumed for a 3M computer . In the late 1980s there were professional displays with resolutions up to 300 dpi (the same as

10680-474: The minimalist, Bauhaus approach to the Spectrum gave it an elegant yet "[non] revolutionary" form. The drawing board on which Dickinson designed the ZX Spectrum is now on display in the Science Museum in London. The need for an improved cassette interface was apparent from the number of complaints received from ZX81 users, who encountered problems when trying to save and load programs. To increase

10800-605: The most influential computers ever made, it is also one of the best-selling British computers ever, with over five million units sold. It was released in the United Kingdom on 23 April 1982, and around the world in the following years, most notably in Europe, the United States, and Eastern Bloc countries. The machine was designed by English entrepreneur and inventor Sir Clive Sinclair and his small team in Cambridge , and

10920-414: The new memory would be available as eight pages of 16 KB at the top of the address space. The same technique was used to page between the new 16 KB editor ROM and the original 16 KB BASIC ROM at the bottom of the address space. The new sound chip and MIDI out abilities were exposed to the BASIC programming language with the command PLAY and a new command SPECTRUM was added to switch

11040-452: The organisation. Given the loss of confidence in the company, securing the funds proved to be a challenging task. In June 1985, business magnate Robert Maxwell disclosed a takeover bid for Sinclair Research through Hollis Brothers, a subsidiary of his Pergamon Press . However, the deal was terminated in August 1985. The future of Sinclair Research remained uncertain until 7 April 1986, when

11160-482: The project. At IETF meeting 101 in March 2018, xvc was presented by Divideon as another candidate. Thor developer Steinar Midtskogen confirmed that a subset of xvc that Divideon considered royalty-free had better compression than Thor at comparable complexity settings. It was agreed at that time to pause physical meetings of the working group to see how the market for royalty-free video formats further developed, given that

11280-453: The quality of 16-bit linear is about equal to 12-bit sRGB . Floating point numbers can represent linear light levels spacing the samples semi-logarithmically. Floating point representations also allow for drastically larger dynamic ranges as well as negative values. Most systems first supported 32-bit per channel single-precision , which far exceeded the accuracy required for most applications. In 1999, Industrial Light & Magic released

11400-475: The rear expansion slot were available from third parties. Both machines had 16 KB of onboard ROM. An "Issue 1" ZX Spectrum can be distinguished from Issue 2 or 3 models by the colour of the keys – light grey for Issue 1, blue-grey for later machines. Although the official service manual states that approximately 26,000 of these original boards were manufactured, subsequent serial number analysis shows that only 16,000 were produced, almost all of which fell in

11520-422: The reference VGA circuit. 256 colors, usually from a fully-programmable palette: Most early color Unix workstations, Super VGA , color Macintosh , Atari TT , Amiga AGA chipset , Falcon030 , Acorn Archimedes . Both X and Windows provided elaborate systems to try to allow each program to select its own palette, often resulting in incorrect colors in any window other than the one with focus. Some systems placed

11640-422: The resolution. Numbers greater than 1 were for colors brighter than the display could show, as in high-dynamic-range imaging (HDRI). Negative numbers can increase the gamut to cover all possible colors, and for storing the results of filtering operations with negative filter coefficients. The Pixar Image Computer used 12 bits to store numbers in the range [-1.5, 2.5), with 2 bits for the integer portion and 10 for

11760-463: The role of microcomputer manufacturer and "accepted the mantle of pioneering boffin leading Britain into a technological utopia". Sinclair's contribution to the technology sector resulted in him being knighted upon the recommendation of Margaret Thatcher in the Queen's 1983 Birthday Honours List . The United Kingdom was largely immunised from the effects of the video game crash of 1983 , due to

11880-454: The same size is added then there are 48 bits per pixel. Using 16 bits per color channel produces 48 bits, 281,474,976,710,656 colors. If an alpha channel of the same size is added then there are 64 bits per pixel. Image editing software such as Adobe Photoshop started using 16 bits per channel fairly early in order to reduce the quantization on intermediate results (i.e. if an operation is divided by 4 and then multiplied by 4, it would lose

12000-519: The saturation of home computers such as the ZX Spectrum. The microcomputer market continued to grow and game development was unhindered despite the turbulence in the American markets. Indeed, computer games remained the dominant sector of the British home video game market up until they were surpassed by Sega and Nintendo consoles in 1991. By the end of 1983 there were more than 450 companies in Britain selling video games on cassette, compared to 95

12120-540: The serial number range 001-000001 to 001-016000. An online tool now exists to allow users to ascertain the likely issue number of their ZX Spectrum by inputting the serial number. These models experienced numerous changes to its motherboard design throughout its life; mainly to improve manufacturing efficiencies, but also to correct bugs from previous boards. Another issue was with the Spectrum's power supply. In March 1983, Sinclair issued an urgent recall warning for all owners of models bought after 1 January 1983. Plugs with

12240-470: The space resolution on LCD screens where the colors have slightly different positions. The DVD-Video and Blu-ray Disc standards support a bit depth of 8 bits per color in YCbCr with 4:2:0 chroma subsampling . YCbCr can be losslessly converted to RGB. MacOS refers to 24-bit colour as "millions of colours". The term true colour is sometimes used to mean what this article is calling direct colour . It

12360-406: The strength of just three primary colors : red, green, and blue. For example, bright yellow is formed by roughly equal red and green contributions, with no blue contribution. For storing and manipulating images, alternative ways of expanding the traditional triangle exist: One can convert image coding to use fictitious primaries, that are not physically possible but that have the effect of extending

12480-462: The system took up slightly less than 7 kilobytes of memory, leaving an additional 9 kilobytes to write programs — a figure that pleased the team. Much of the firmware was written by computer scientist Steve Vickers from Nine Tiles, who compiled all control routines to produce the Sinclair BASIC interpreter, a custom variant of the general purpose BASIC programming language. Making

12600-492: The team aimed for data transfer speed of 1000 baud , but succeeded in getting it to work at a considerably faster 1500 baud. Unlike the ZX81, the Spectrum was able to maintain its display during loading and saving operations, and programmers took advantage of this to show a splash screen whilst loading took place in the background. As with the ZX81, the ZX Spectrum was manufactured in Dundee , Scotland, by Timex Corporation at

12720-409: The team had to divorce the central processing unit (CPU) away from the main display to enable it to work at full efficiency – a method which contrasted with the ZX81's integrated CPU. The inclusion of colour to the display proved a major obstacle to the engineers. A Teletext -like approach was briefly considered, in which each line of text would have colour-change codes inserted into it. However, this

12840-754: The teams behind several of the format candidates that had been presented had chosen to join the AV1 standard development initiative of the Alliance for Open Media consortium, which had similar goals. After publishing RFC 8761 "Video Codec Requirements and Evaluation Methodology" in April 2020, the Internet Video Codec working group was closed. The planned schedule for the development of NETVC was: Color depth Color depth or colour depth (see spelling differences ), also known as bit depth ,

12960-433: The triangle to enclose a much larger color gamut. An equivalent, simpler change is to allow negative numbers in color channels, so that the represented colors can extend out of the color triangle formed by the primaries. However these only extend the colors that can be represented in the image encoding; neither trick extends the gamut of colors that can actually be rendered on a display device. Supplementary colors can widen

13080-419: The whole of the first year. By August 1983 total sales in Britain and Europe had exceeded 500,000, with the millionth Spectrum manufactured on 9 December 1983. By this point, an average of 50,000 units were being purchased each month. In July 1983, the ZX Spectrum was launched in the United States as the more enhanced Timex Sinclair 2068 . Advertisements described it as offering 72 kilobytes of memory, having

13200-402: The year before. An estimated 10,000 to 50,000 people, mostly young men, were developing games out of their homes based on advertisements in popular magazines. The growth of video games during this period has been compared to the punk subculture , fuelled by young people making money from their games. By the mid 1980s, Sinclair Research's share of the British home computer market had climbed to

13320-499: Was dubbed "colour clash" or attribute clash , where a desired colour of a specific pixel could not be selected, but only the colour attributes of an 8x8 block. This became a distinctive feature of the Spectrum, requiring programs, especially games, to be designed with this limitation in mind. In contrast, other machines available at the same time, such as the Amstrad CPC or the Commodore 64 , did not suffer from this limitation. While

13440-428: Was expanded compared to that of the ZX81, which lacked lowercase letters. Spectrum BASIC incorporated extra keywords for better graphics and sound functionality, and support for multi-statement lines was added. The built-in ROM tape modulation software routines for cassette data storage enable data transfers at an average speed of 171 bits per second (bit/s), with a theoretical peak speed of 256 bit/s. The tape modulation

13560-604: Was issued as a prize. The ZX Spectrum's successor, the Sinclair QL , was officially announced on 12 January 1984, shortly before the Apple Macintosh went on sale. Contrasting with its predecessors, the QL was aimed at more serious, professional home users. It suffered from several design flaws; fully operational QLs were not available until the late summer, and complaints against Sinclair concerning delays were upheld by

13680-423: Was manufactured in Dundee , Scotland by Timex Corporation . It was made to be small, simple, and most importantly inexpensive, with as few components as possible. The addendum "Spectrum" was chosen to highlight the machine's colour display, which differed from the black-and-white display of its predecessor, the ZX81 . Rick Dickinson designed its distinctive case, rainbow motif, and rubber keyboard . Video output

13800-469: Was often set to a 16×16×16 color cube). Some Silicon Graphics systems, Color NeXTstation systems, and Amiga systems in HAM mode have this color depth. RGBA4444, a related 16 bpp representation providing the color cube and 16 levels of transparency, is a common texture format in mobile graphics. In high-color systems, two bytes (16 bits) are stored for each pixel. Most often, each component (R, G, and B)

13920-660: Was presented to the IETF as a candidate for NETVC. Daala coding techniques have been proposed to the IETF for inclusion into NETVC. On July 22, 2015, Cisco's Thor video codec was presented to the IETF as a candidate for their NETVC video standard. Thor is being developed by Cisco Systems and uses some Cisco elements that are also used by HEVC. The Constrained Low-Pass Filter (CLPF) and motion compensation that are used in Thor were tested with Daala. As of July 2015, in addition to Xiph and Cisco, there were also other participants involved in

14040-449: Was reduced in price to £129. In 1985, Sinclair developed the ZX Spectrum 128 (codenamed Derby ) in conjunction with their Spanish distributor Investrónica (a subsidiary of El Corte Inglés department store group). Investrónica had helped adapt the ZX Spectrum+ to the Spanish market after their government introduced a special tax on all computers with 64 KB RAM or less, and a law which obliged all computers sold in Spain to support

14160-470: Was ruled out, as it was deemed unsuitable for high-resolution graphs or diagrams that involved multiple colour changes. Altwasser devised the idea of allocating a colour attribute to each character position on the screen. This ultimately used eight bits of memory for each character position; three bits to provide any one of eight foreground colours and three bits for the eight background colours , one bit for extra brightness and one bit for flashing. Overall,

14280-421: Was the most common use of home computers. Due to the large number of unsold Spectrum+ models, Sinclair decided not to start it selling in the United Kingdom until January 1986 at a price of £179. The Zilog Z80 processor used in the Spectrum has a 16-bit address bus, which means only 64 KB of memory can be directly addressed. To facilitate the extra 80 KB of RAM the designers used bank switching so

14400-527: Was well known for his eccentricity and pioneering ethic. On 25 July 1961, three years after passing his A-levels , he founded Sinclair Radionics Ltd as a vehicle to advertise his inventions and buy components. In 1972, Sinclair had competed with Texas Instruments to produce the world's first pocket calculator , the Sinclair Executive . By the mid 1970s, Sinclair Radionics was producing handheld electronic calculators, miniature televisions, and

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