sentence-transformers/squad huggingface dataset:
Passage: The British high-definition TV service started trials in August 1936 and a regular service on 2 November 1936 using both the (mechanical) Baird 240 line sequential scan (later to be inaccurately rechristened 'progressive') and the (electronic) Marconi-EMI 405 line interlaced systems. The Baird system was discontinued in February 1937. In 1938 France followed with their own 441-line system, variants of which were also used by a number of other countries. The US NTSC 525-line system joined in 1941. In 1949 France introduced an even higher-resolution standard at 819 lines, a system that should have been high definition even by today's standards, but was monochrome only and the technical limitations of the time prevented it from achieving the definition of which it should have been capable. All of these systems used interlacing and a 4:3 aspect ratio except the 240-line system which was progressive (actually described at the time by the technically correct term "sequential") and the 405-line system which started as 5:4 and later changed to 4:3. The 405-line system adopted the (at that time) revolutionary idea of interlaced scanning to overcome the flicker problem of the 240-line with its 25 Hz frame rate. The 240-line system could have doubled its frame rate but this would have meant that the transmitted signal would have doubled in bandwidth, an unacceptable option as the video baseband bandwidth was required to be not more than 3 MHz.

Question: Who started trials in August 1936?

Question: When was the Baird system discontinued?

Question: Which country developed the 441-line system?

Question: What prevented France's 819-line system from achieving the definition it was capable of?

Question: Which system used interlaced scanning to correct the flicker problem of the 240-line?
Passage: Colour broadcasts started at similarly higher resolutions, first with the US NTSC color system in 1953, which was compatible with the earlier monochrome systems and therefore had the same 525 lines of resolution. European standards did not follow until the 1960s, when the PAL and SECAM color systems were added to the monochrome 625 line broadcasts.

Question: What year did color broadcasts start in the US?

Question: How many lines of resolution did the US NTSC color system have in 1953?

Question: When did Europe begin color broadcasts?

Question: The PAL and SECAM were color systems where?

Question: How many lines of resolution were the European monochrome broadcasts?
Passage: The Nippon Hōsō Kyōkai (NHK, the Japan Broadcasting Corporation) began conducting research to "unlock the fundamental mechanism of video and sound interactions with the five human senses" in 1964, after the Tokyo Olympics. NHK set out to create an HDTV system that ended up scoring much higher in subjective tests than NTSC's previously dubbed "HDTV". This new system, NHK Color, created in 1972, included 1125 lines, a 5:3 aspect ratio and 60 Hz refresh rate. The Society of Motion Picture and Television Engineers (SMPTE), headed by Charles Ginsburg, became the testing and study authority for HDTV technology in the international theater. SMPTE would test HDTV systems from different companies from every conceivable perspective, but the problem of combining the different formats plagued the technology for many years.

Question: What is the Japan Broadcasting Corporation called?

Question: What does NHK stand for in Japan?

Question: What year was NHK Color created?

Question: What was the aspect ratio of the NHK Color?

Question: What organization became the authority on testing and studying international HDTV technology?
Passage: There were four major HDTV systems tested by SMPTE in the late 1970s, and in 1979 an SMPTE study group released A Study of High Definition Television Systems:

Question: How many major HDTV systems were tested by SMPTE in the late 70's?

Question: Who tested the four major HDTV systems in the late 1970's?

Question: Who released A Study of High Definition Television Systems?

Question: In what year was A Study of High Definition Television Systems released?

Question: What was released by an SMPTE study group in 1979?
Passage: Since the formal adoption of digital video broadcasting's (DVB) widescreen HDTV transmission modes in the early 2000s; the 525-line NTSC (and PAL-M) systems, as well as the European 625-line PAL and SECAM systems, are now regarded as standard definition television systems.

Question: What does DVB stand for?

Question: When was widescreen HDTV transmission modes formally adopted?

Question: In addition to the 625-line PAL system, what European system is considered a standard definition television system?

Question: In addition to the NTSC system, what 525-line system is considered a standard definition television system?

Question: 525 and 625-line systems are now considered what?
Passage: In 1949, France started its transmissions with an 819 lines system (with 737 active lines). The system was monochrome only, and was used only on VHF for the first French TV channel. It was discontinued in 1983.

Question: In what year did France start transmissions using and 819 line system?

Question: What country started transmissions using and 819 line system in 1949?

Question: What did France start transmissions with in 1949?

Question: Was France's 819 line system in color?

Question: When was France's 819 line system discontinued?
Passage: In 1958, the Soviet Union developed Тransformator (Russian: Трансформатор, meaning Transformer), the first high-resolution (definition) television system capable of producing an image composed of 1,125 lines of resolution aimed at providing teleconferencing for military command. It was a research project and the system was never deployed by either the military or consumer broadcasting.

Question: In the end what was the Soviet Union's Transformator system used for?

Question: When did the Soviet Union develop Transformator?

Question: Who developed Transformator in 1958?

Question: How many lines of resolution could an image using the Transformator system have?

Question: What was the goal of the Transformator system?
Passage: In 1979, the Japanese state broadcaster NHK first developed consumer high-definition television with a 5:3 display aspect ratio. The system, known as Hi-Vision or MUSE after its Multiple sub-Nyquist sampling encoding for encoding the signal, required about twice the bandwidth of the existing NTSC system but provided about four times the resolution (1080i/1125 lines). Satellite test broadcasts started in 1989, with regular testing starting in 1991 and regular broadcasting of BS-9ch commencing on November 25, 1994, which featured commercial and NHK programming.

Question: In what year did NHK first develop consumer HD television with a 5:3 aspect ratio?

Question: Who first developed consumer HD television with a 5:3 aspect ratio?

Question: When did satellite test broadcasts of Hi-Vision start?

Question: When did regular broadcasting of BS-9ch start?

Question: When did regular testing of Hi-Vision start?
Passage: In 1981, the MUSE system was demonstrated for the first time in the United States, using the same 5:3 aspect ratio as the Japanese system. Upon visiting a demonstration of MUSE in Washington, US President Ronald Reagan was impressed and officially declared it "a matter of national interest" to introduce HDTV to the US.

Question: When was the MUSE system demonstrated in the US first?

Question: What aspect ratio did the MUSE system use when demonstrated in 1981?

Question: Which president declared it "a matter of national interest" to introduce HDTV to the US?

Question: Which system was demonstrated in the US for the first time in 1981?

Question: Which system was demonstrated in Washington to President Ronald Reagan?
Passage: Several systems were proposed as the new standard for the US, including the Japanese MUSE system, but all were rejected by the FCC because of their higher bandwidth requirements. At this time, the number of television channels was growing rapidly and bandwidth was already a problem. A new standard had to be more efficient, needing less bandwidth for HDTV than the existing NTSC.

Question: Why did the FCC reject systems such as MUSE?

Question: What was increasing and consuming a lot of bandwidth?

Question: Who rejected systems such as MUSE as the new standard for the US?

Question: What was one of the requirements for a new standard system in the US?

Question: What was the existing system at the time?
Passage: The limited standardization of analog HDTV in the 1990s did not lead to global HDTV adoption as technical and economic constraints at the time did not permit HDTV to use bandwidths greater than normal television.

Question: What constraints kept HDTV from being widely adopted in the 90's?

Question: What was HDTV not permitted to do in the 90's?
Passage: Early HDTV commercial experiments, such as NHK's MUSE, required over four times the bandwidth of a standard-definition broadcast. Despite efforts made to reduce analog HDTV to about twice the bandwidth of SDTV, these television formats were still distributable only by satellite.

Question: How much more bandwith was required from early HDTV commercial experiments than an SD broadcast?

Question: Efforts were made to reduce analog HDTV to how much of the bandwith of SDTV?

Question: Despite the reduced bandwith, HDTV format still had to be distributed how?

Question: What kind of experiments required over four times the bandwith of a SDTV broadcast?
Passage: In addition, recording and reproducing an HDTV signal was a significant technical challenge in the early years of HDTV (Sony HDVS). Japan remained the only country with successful public broadcasting of analog HDTV, with seven broadcasters sharing a single channel.

Question: How many broadcasters did Japan have sharing a single channel?

Question: Which country had successful public analog HDTV broadcasting?

Question: What was particularly challenging in the early years of HDTV?

Question: What accomplishment in early HDTV did Japan have?
Passage: Since 1972, International Telecommunication Union's radio telecommunications sector (ITU-R) had been working on creating a global recommendation for Analog HDTV. These recommendations, however, did not fit in the broadcasting bands which could reach home users. The standardization of MPEG-1 in 1993 also led to the acceptance of recommendations ITU-R BT.709. In anticipation of these standards the Digital Video Broadcasting (DVB) organisation was formed, an alliance of broadcasters, consumer electronics manufacturers and regulatory bodies. The DVB develops and agrees upon specifications which are formally standardised by ETSI.

Question: What does ITU-R stand for?

Question: What does DVB stand for?

Question: What is the DVB?

Question: What is the DVB's role?

Question: Who standardizes HDTV specifications?
Passage: DVB created first the standard for DVB-S digital satellite TV, DVB-C digital cable TV and DVB-T digital terrestrial TV. These broadcasting systems can be used for both SDTV and HDTV. In the US the Grand Alliance proposed ATSC as the new standard for SDTV and HDTV. Both ATSC and DVB were based on the MPEG-2 standard, although DVB systems may also be used to transmit video using the newer and more efficient H.264/MPEG-4 AVC compression standards. Common for all DVB standards is the use of highly efficient modulation techniques for further reducing bandwidth, and foremost for reducing receiver-hardware and antenna requirements.

Question: What did the Grand Alliance propose as the new standard for SDTV and HDTV?

Question: Which standard were ATSC and DVB based on?

Question: Who created the standard for DVB-2, DVB-C, and DVB-T?

Question: Who proposed ATSC as the new standard for SDTV and HDTV?
Passage: In 1983, the International Telecommunication Union's radio telecommunications sector (ITU-R) set up a working party (IWP11/6) with the aim of setting a single international HDTV standard. One of the thornier issues concerned a suitable frame/field refresh rate, the world already having split into two camps, 25/50 Hz and 30/60 Hz, largely due to the differences in mains frequency. The IWP11/6 working party considered many views and throughout the 1980s served to encourage development in a number of video digital processing areas, not least conversion between the two main frame/field rates using motion vectors, which led to further developments in other areas. While a comprehensive HDTV standard was not in the end established, agreement on the aspect ratio was achieved.

Question: When did ITU-R start trying to work towards setting a single international HDTV standard?

Question: What did ITU-R start trying to do in 1983?

Question: What was one of the issues with setting a single HDTV standard?

Question: What was used as a conversion between the two main frame/field rates?

Question: How many frame/field rates were primarily being used in 1983?
Passage: Initially the existing 5:3 aspect ratio had been the main candidate but, due to the influence of widescreen cinema, the aspect ratio 16:9 (1.78) eventually emerged as being a reasonable compromise between 5:3 (1.67) and the common 1.85 widescreen cinema format. An aspect ratio of 16:9 was duly agreed upon at the first meeting of the IWP11/6 working party at the BBC's Research and Development establishment in Kingswood Warren. The resulting ITU-R Recommendation ITU-R BT.709-2 ("Rec. 709") includes the 16:9 aspect ratio, a specified colorimetry, and the scan modes 1080i (1,080 actively interlaced lines of resolution) and 1080p (1,080 progressively scanned lines). The British Freeview HD trials used MBAFF, which contains both progressive and interlaced content in the same encoding.

Question: What aspect ratio was agreed upon due to the influence of widescreen cinema?

Question: Who agreed upon the 16:9 aspect ratio?

Question: What was a leading factor in the 16:9 aspect ratio being chosen?

Question: Which encoding contains both progressive and interlaced content?

Question: Which aspect ratio was the early favorite?
Passage: It also includes the alternative 1440×1152 HDMAC scan format. (According to some reports, a mooted 750-line (720p) format (720 progressively scanned lines) was viewed by some at the ITU as an enhanced television format rather than a true HDTV format, and so was not included, although 1920×1080i and 1280×720p systems for a range of frame and field rates were defined by several US SMPTE standards.)

Question: What scan format is also included in MBAFF?

Question: What was viewed by some as enhanced television format and not true HDTV format?

Question: A mooted 750-line was seen by some at the ITU as what?

Question: What were 1920x1080i and 1280x720p defined by?
Passage: HDTV technology was introduced in the United States in the late 1980s and made official in 1993 by the Digital HDTV Grand Alliance, a group of television, electronic equipment, communications companies consisting of AT&T Bell Labs, General Instrument, Philips, Sarnoff, Thomson, Zenith and the Massachusetts Institute of Technology. Field testing of HDTV at 199 sites in the United States was completed August 14, 1994. The first public HDTV broadcast in the United States occurred on July 23, 1996 when the Raleigh, North Carolina television station WRAL-HD began broadcasting from the existing tower of WRAL-TV southeast of Raleigh, winning a race to be first with the HD Model Station in Washington, D.C., which began broadcasting July 31, 1996 with the callsign WHD-TV, based out of the facilities of NBC owned and operated station WRC-TV. The American Advanced Television Systems Committee (ATSC) HDTV system had its public launch on October 29, 1998, during the live coverage of astronaut John Glenn's return mission to space on board the Space Shuttle Discovery. The signal was transmitted coast-to-coast, and was seen by the public in science centers, and other public theaters specially equipped to receive and display the broadcast.

Question: When was HDTV introduced in the US?

Question: Who made HDTV official in 1993?

Question: AT&T, Philips, Zenith, and MIT, among others, made up what group in the 90's?

Question: When did the first public HDTV broadcast happen in the US?

Question: What does ATSC stand for?
Passage: The first HDTV transmissions in Europe, albeit not direct-to-home, began in 1990, when the Italian broadcaster RAI used the HD-MAC and MUSE HDTV technologies to broadcast the 1990 FIFA World Cup. The matches were shown in 8 cinemas in Italy and 2 in Spain. The connection with Spain was made via the Olympus satellite link from Rome to Barcelona and then with a fiber optic connection from Barcelona to Madrid. After some HDTV transmissions in Europe the standard was abandoned in the mid-1990s.

Question: When did the first HDTV transmissions happen in Europe?

Question: What event was the first HDTV broadcast in Europe?

Question: When did Europe abandon standard transmission?

Question: Where was the FIFA World Cup able to be watched in HDTV?
Passage: The first regular broadcasts started on January 1, 2004 when the Belgian company Euro1080 launched the HD1 channel with the traditional Vienna New Year's Concert. Test transmissions had been active since the IBC exhibition in September 2003, but the New Year's Day broadcast marked the official launch of the HD1 channel, and the official start of direct-to-home HDTV in Europe.

Question: When did regular broadcasts start in Europe?

Question: What event was first broadcasted on January 1, 2004?

Question: The New Year's Day broadcast officially launched which channel?

Question: When did test transmissions of HDTV begin in Europe?

Question: Which European company launched HD1?
Passage: Euro1080, a division of the former and now bankrupt Belgian TV services company Alfacam, broadcast HDTV channels to break the pan-European stalemate of "no HD broadcasts mean no HD TVs bought means no HD broadcasts ..." and kick-start HDTV interest in Europe. The HD1 channel was initially free-to-air and mainly comprised sporting, dramatic, musical and other cultural events broadcast with a multi-lingual soundtrack on a rolling schedule of 4 or 5 hours per day.

Question: Euro1080 was a division of what former company?

Question: What "chicken or the egg" stalemate prompted Euro1080 to broadcast HDTV channels?

Question: What was Euro1080 hoping to kick-start by broadcasting HDTV channels?

Question: How much did viewers have to pay for the HD1 channel?

Question: What was on HD1 for 4 or 5 hours per day?
Passage: These first European HDTV broadcasts used the 1080i format with MPEG-2 compression on a DVB-S signal from SES's Astra 1H satellite. Euro1080 transmissions later changed to MPEG-4/AVC compression on a DVB-S2 signal in line with subsequent broadcast channels in Europe.

Question: What format did the first European HDTV broadcast use?

Question: What compression did the first European HDTV broadcast use?

Question: What signal did the first European HDTV broadcast use?

Question: What compression did Euro1080 later change to?

Question: What signal did Euro1080 later change to?
Passage: Despite delays in some countries, the number of European HD channels and viewers has risen steadily since the first HDTV broadcasts, with SES's annual Satellite Monitor market survey for 2010 reporting more than 200 commercial channels broadcasting in HD from Astra satellites, 185 million HD capable TVs sold in Europe (£60 million in 2010 alone), and 20 million households (27% of all European digital satellite TV homes) watching HD satellite broadcasts (16 million via Astra satellites).

Question: According to the 2010 Satellite Monitor market survey, how many HD capable TV's were sold in Europe?

Question: According to the 2010 Satellite Monitor market survey, how many European households were watching HD broadcasts?

Question: How many pounds were spent in Europe on HD capable TVs in 2010?

Question: What percentage of European digital satellite TV homes were watching HD broadcasts in 2010?

Question: The number of European HD channels and viewers has done what since the first HDTV broadcasts?
Passage: In December 2009 the United Kingdom became the first European country to deploy high definition content using the new DVB-T2 transmission standard, as specified in the Digital TV Group (DTG) D-book, on digital terrestrial television.

Question: Which European country first deployed HD content using the new DVB-T2 standard?

Question: When did the UK deploy HD content using the new DVB-T2 transmission standard?

Question: What transmission standard did the UK start using in December 2009?

Question: What does DTG stand for?
Passage: The Freeview HD service currently contains 10 HD channels (as of December 2013[update]) and was rolled out region by region across the UK in accordance with the digital switchover process, finally being completed in October 2012. However, Freeview HD is not the first HDTV service over digital terrestrial television in Europe;

Question: How many HD channels did the Freeview HD service contain as of December 2013?

Question: When was the digital switchover process completed in the UK?

Question: Which service contains 10 HD channels and finished its roll out in October 2012?

Question: How was the Freeview HD service rolled out in the UK?
Passage: If all three parameters are used, they are specified in the following form: [frame size][scanning system][frame or field rate] or [frame size]/[frame or field rate][scanning system].[citation needed] Often, frame size or frame rate can be dropped if its value is implied from context. In this case, the remaining numeric parameter is specified first, followed by the scanning system.

Question: What are the three HDTV parameters?

Question: Which two parameters can be dropped if its value is implied from context?

Question: When can the frame size or frame rate parameter specification be dropped?

Question: When a parameter is dropped, the remaining numeric parameter is specified first, followed by what?
Passage: For example, 1920×1080p25 identifies progressive scanning format with 25 frames per second, each frame being 1,920 pixels wide and 1,080 pixels high. The 1080i25 or 1080i50 notation identifies interlaced scanning format with 25 frames (50 fields) per second, each frame being 1,920 pixels wide and 1,080 pixels high. The 1080i30 or 1080i60 notation identifies interlaced scanning format with 30 frames (60 fields) per second, each frame being 1,920 pixels wide and 1,080 pixels high. The 720p60 notation identifies progressive scanning format with 60 frames per second, each frame being 720 pixels high; 1,280 pixels horizontally are implied.

Question: What size is each 1920x1080p25 frame?

Question: The 1920x1080p25 notion identifies progressive scanning format with how many frames per second?

Question: The 1080i25 or 1080i50 notion identifies interlaced scanning format with how many frames per second?

Question: The 1080i30 or 1080i60 notion identifies interlaced scanning format with how many frames per second?

Question: The 720p60 notion identifies progressive scanning format with how many frames per second?
Passage: 50 Hz systems support three scanning rates: 50i, 25p and 50p. 60 Hz systems support a much wider set of frame rates: 59.94i, 60i, 23.976p, 24p, 29.97p, 30p, 59.94p and 60p. In the days of standard definition television, the fractional rates were often rounded up to whole numbers, e.g. 23.976p was often called 24p, or 59.94i was often called 60i. 60 Hz high definition television supports both fractional and slightly different integer rates, therefore strict usage of notation is required to avoid ambiguity. Nevertheless, 29.97i/59.94i is almost universally called 60i, likewise 23.976p is called 24p.

Question: What three scanning rates do 50 Hz systems support?

Question: Which system suports 59.94i, 60i, 23.976p, 24p, 29.97p, 30p, 59.94p, and 60p

Question: SD television fractional rates were often rounded to what?

Question: Strict notation is required with HD fractional rates to avoid what?