PALplus is an extension of the
PALPAL, short for Phase Alternating Line, is an analogue television encoding system used in broadcast television systems in large parts of the world. Other common analogue television systems are SECAM and NTSC. This page primarily discusses the colour encoding system...
analogue broadcasting system for transmitting 16:9 programs without sacrificing vertical resolution. It followed experiences with the
HD-MACHD-MAC was a proposed television standard by the European Commission in 1986 . It was an early attempt by the EEC to provide HDTV in Europe. It was a complex mix of analogue signal , multiplexed with digital sound...
and
D2-MACD2-MAC was created to solve D-MAC's bandwidth problem on European cable systems.* D2-MAC uses half the data rate of D-MAC {10.125Mb/s}* D2-MAC has a reduced vision bandwidth, about 1/2 that of D-MAC....
, standards that were incompatible with existing receivers but featured a 16:9 aspect ratio. It was developed in Germany (University of Dortmund in cooperation with German terrestrial broadcasters and European and Japanese manufacturers.
A standard PAL receiver will display the image in letterbox format with 432 active lines, while a
PALplus receiver can use extra information hidden in the black bars above and below the image to recreate 576 lines of vertical resolution.
A special
signalIn television technology, widescreen signaling is a digital stream embedded in the TV signal describing qualities of the broadcast, in particular the intended aspect ratio of the image...
tells the receiver when PALplus is in use, and also whether the original content was
interlaceIn the domain of mechanical television, the concept of interlacing was demonstrated by Léon Theremin. He had been developing a mirror drum-based television, starting with 16 lines resolution in 1925, then 32 lines and eventually 64 using interlacing in 1926, and as part of his thesis on May 7, 1926...
d ("Camera mode" 576i50) or
progressive scanProgressive or noninterlaced scanning is a method for displaying, storing or transmitting moving images in which all the lines of each frame are drawn in sequence...
ned ("Film mode" 576p25). An additional signal can enable a "
GhostIn television, a ghost is a replica of the transmitted image, offset in position, that is super-imposed on top of the main image.-Common causes:Common causes of ghosts are:...
Cancellation" feature.
A separate feature related to PALplus is
ColourPlus, which improves colour decoding performance.
Operation
Without PALplus, a 16:9 presentation has only 432 lines of vertical resolution. This reproduces noticeably less detail than the 576 lines used for 4:3 broadcasts. A fully decoded PALplus broadcast restores the 576 line vertical resolution. For compatibility reasons, the horizontal bandwidth remains at 5.0 MHz. This means a PALplus signal provides no extra horizontal resolution to compensate for the image being stretched across a wider screen. The result is a horizontal resolution that is 73% of the vertical resolution, or 51% when the
Kell factorThe Kell Factor, named after RCA engineer Raymond D. Kell, is a parameter used to limit the bandwidth of a sampled image signal as to avoid beat frequency patterns to appear when displaying the image in a discrete display devices, usually taken to be 0.7. The number was first measured in 1934 by...
is ignored.
The PALplus standard comprises three extensions to standard PAL:
Vertical helper
A broadcaster creates a PALplus signal by scaling an
anamorphicAnamorphic widescreen is a videographic technique using rectangular pixels to store a widescreen image to standard 4:3 aspect ratio. In its current definition as a video term, it was originally devised for widescreen 16:9 aspect ratio television sets.-DVD Video:DVDs using anamorphic widescreen are...
16:9 picture with 576 lines down to 432 lines, so that the picture appears
letterboxLetterboxing is the practice of transferring film shot in a widescreen aspect ratio to standard-width video formats while preserving the film's original aspect ratio. The resulting videographic image has mattes above and below it; these mattes are part of the image...
ed on a regular PAL TV set. For luminance, the scaling is done using a pair of matching low-pass and high-pass filters, with the low-pass result appearing in the broadcast. One out of every 4 lines of the high-pass result is then hidden in the remaining 144 black lines at the top and bottom of the picture, using the
UYUV is a color space typically used as part of a color image pipeline. It encodes a color image or video taking human perception into account, allowing reduced bandwidth for chrominance components, thereby typically enabling transmission errors or compression artifacts to be more efficiently...
colour subcarrier. The filtering is such that this is enough to restore the complete 576 line resolution. The use of the colour subcarrier means the signals sometimes appear as blue and yellow patterns on a regular PAL TV set. The 16:9 PAL-plus receiver combines 432 visible lines plus 144 helper lines into 576 new visible lines.
In Film mode (
progressive scanProgressive or noninterlaced scanning is a method for displaying, storing or transmitting moving images in which all the lines of each frame are drawn in sequence...
), the operation is performed on a per-frame basis, while in Camera mode (interlaced) the operation is performed per-field.
Colour-plus (or Clean PAL)
The PAL colour carrier is modulated making use of
correlationIn statistics, correlation indicates the strength and direction of a relationship between two random variables. The commonest use refers to a linear relationship. In general statistical usage, correlation or co-relation refers to the departure of two random variables from independence...
between 2 fields, in order to give a cleaner Y/C separation in the PAL-plus receiver. It is used with signals with high horizontal luminance frequencies (3Mhz) that share the spectrum with the chrominance signals. Colour pictures on both standard and PAL Plus receivers are enhanced.
For progressive "Film mode" material, "Fixed" Colour-Plus is used, as there is no motion between the image fields.
For camera based images, "Motion Adaptive Color-Plus" (MACP) is used based on movement.
Signaling bits
A special
WSS signalIn television technology, widescreen signaling is a digital stream embedded in the TV signal describing qualities of the broadcast, in particular the intended aspect ratio of the image...
tells the receiver whether 4:3/16:9/PALplus is in use, and also whether the original content was
interlaceIn the domain of mechanical television, the concept of interlacing was demonstrated by Léon Theremin. He had been developing a mirror drum-based television, starting with 16 lines resolution in 1925, then 32 lines and eventually 64 using interlacing in 1926, and as part of his thesis on May 7, 1926...
d ("Camera mode") or
progressive scanProgressive or noninterlaced scanning is a method for displaying, storing or transmitting moving images in which all the lines of each frame are drawn in sequence...
ned ("Film mode"). An additional signal can enable a "
GhostGhosting may refer to:* ghosting , a double image when receiving a distorted or multipath input signal in analog television broadcasting...
Cancellation" feature. The bandwidth of these bits is low enough to be recorded on VHS and allow the receiver to switch to the proper format.
PAL-plus compatible sets
The standard permits using the mark "PAL-plus" if just the vertical helper reconstruction implemented, with Colour-plus being optional.
Some PALPlus compatible sets:
- Grundig
Grundig AG is a German manufacturer of consumer electronics for home entertainment under Turkish control. Established in 1945 in Nuremberg, Germany by Max Grundig the company changed hands several times before becoming part of the Turkish Koç Holding group...
: MFW82-710/9, MFW82-720/9, MFW82-730/9 DVD
- Philips
Koninklijke Philips Electronics N.V. , most commonly known as Philips, is a Dutch electronics company.Philips is one of the largest electronics companies in the world. In 2007, its sales were €26.79 billion...
: 28PW9525, 32PW9525, 36PW9525
- Schneider
-Various:* Schneider , a German family name* Point counts in the card games Sheepshead and Skat* Schneider , an Argentinian brand of beer* Schneider CA1, a French World War I tank* Schneider Trophy, a prize for seaplanes...
: Scinema 28-100T, Scinema 2810, Scinema 3000
Most widescreen sets without any PAL-plus processing will switch the display format automatically between 4:3 and 16:9, based on the signaling bits. These sets will display only the centre 432 lines of the 4:3 image, to fill all of the 16:9 frame.
Belgium
In
BelgiumThe Kingdom of Belgium is a country in northwest Europe. It is a founding member of the European Union and hosts its headquarters, as well as those of other major international organizations, including NATO...
, the Flemish public broadcasting service
VRTThe Vlaamse Radio- en Televisieomroep , or VRT, is a publicly-funded broadcaster of radio and television in Flanders ....
has a policy that all of its self-created TV programmes are broadcast in PALplus. For example the news is broadcast daily in PALPlus, as are almost all of the weekly scheduled shows. VRT does however always respect the original ratio of the footage. So new films and series are usually broadcast in PALplus. The commercial TV station
VTMThe abbreviation VTM may refer to::* Vampire: The Masquerade, a popular role-playing game* Video Training Module, a video produced by 3D Buzz for the purpose of education in a variety of different computer-related media including CG software such as Autodesk Maya, Autodesk 3ds Max, and programming...
also broadcasts a lot in PALplus. The
VTMThe abbreviation VTM may refer to::* Vampire: The Masquerade, a popular role-playing game* Video Training Module, a video produced by 3D Buzz for the purpose of education in a variety of different computer-related media including CG software such as Autodesk Maya, Autodesk 3ds Max, and programming...
news for example is also broadcast in PALplus. So are the commercials. Special shows and films are always broadcast in PALplus too. VTM tends to change 4/3 footage to 16/9 too. Even the third broadcasting organisation SBS Belgium with its stations
VT4VT4 is a Flemish commercial television channel. It is part of ProSiebenSat.1 Media AG.The channel began broadcasting on 1 February 1995. The channel initially had no Belgian broadcasting license and was transmitted via London . The channel now broadcasts legally from Zaventem in Belgium...
and
VijfTVVIJFtv started in october 2004 as SBS Belgium's second channel and a sister channel to VT4. The first thing VIJFtv broadcast was a soccer game. By doing that the station made sure men would set their TV up to view VIJFtv....
broadcast in PALplus for all of their new productions and they also broadcast the news and the commercials in P+.
The Walloon public broadcasting service
RTBFRTBF or Radio télévision belge de la communauté française is the national broadcasting organisation of the government of the French-speaking southern part of Belgium, the counterpart to the Dutch-speaking VRT in the northern part of the country...
broadcasts bought 16:9 programmes in PALplus, like films, but chooses to create their own programmes in 4:3. Walloon commercial TV station RTL-TVi now broadcasts almost all its shows in PALPlus and tends to convert its old shows to 16/9 too.
Germany
In
GermanyGermany , officially the Federal Republic of Germany , is a country in Central Europe. It is bordered to the north by the North Sea, Denmark, and the Baltic Sea; to the east by Poland and the Czech Republic; to the south by Austria and Switzerland; and to the west by France, Luxembourg, Belgium,...
all public broadcasters (ARD,
ZDFZweites Deutsches Fernsehen , ZDF, is a public-service German television channel based in Mainz. It is run as an independent non-profit agency established by joint contract between the German federal states...
,
etc) comply with this standard. However, private broadcasters (
RTLRTL Television is a German commercial television station distributed via cable and satellite along with DVB-T...
, Pro Sieben,
etc) have shown no interest in either this standard or in the 16:9 format.
Pay-per-view channels such as
PremiereA premiere is generally "a first performance." This can refer to plays, films, television programs, operas, symphonies, and so on. Premieres for theatrical, musical and other cultural presentations can become extravagant affairs, attracting large numbers of socialites and much media attention...
often broadcast in 16:9, but use a different standard that requires another kind of decoder.
Netherlands
In the Netherlands the public broadcasters used PALplus until 2005 but have stopped using it because they preferred digital tv (anamorphic widescreen) over PALplus. The public broadcasters and all the major commercial stations have a policy of broadcasting their own and new shows in widescreen, this isn't converted to PALplus on the analogue signal of the cable operators. As cable is the most widespread form of receiving television in the Netherlands the system isn't used anymore. Terrestrial analogue signals stopped in November 2006 in this country.
Portugal
In
PortugalPortugal , officially the Portuguese Republic , is a country located in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of mainland Europe and is bordered by the Atlantic Ocean to the west and south and by Spain to the north and east...
, the private broadcaster
TVITVI - Televisão Independente is Portugal's fourth terrestrial television channel, launched in 1993. It is the leader of audiences in its country since 2004. It competes directly with SIC and RTP1.-History:...
began broadcasting movies in PALplus in 1994, but some years after it left the standard behind.
The public broadcaster RTP started using the format in 1997. Today it still uses the system to broadcast selected programs (about five programs each day) and some widescreen movies on analog terrestrial broadcasts. Cable distributors ocasionaly strip the signal of the WSS bits, rendering the system inoperative. Also, although Digital Terrestrial Television broadcasts have started there are no dedicated anamorphic simulcast for the digital channels. Therefore, PALPlus over terrestrial analog PAL broadcasts remains the only source of 576 lines widescreen TV in Portugal.
Finland
In
FinlandFinland , officially the Republic of Finland
, is a Nordic country and democracy situated in the Fennoscandian region of northern Europe. It borders Sweden on the west, Russia on the east, and Norway on the north, while Estonia lies to its south across the Gulf of Finland...
, the commercial broadcaster
MTV3MTV3 is a Finnish commercial television station owned by Bonnier. Until recently it had the biggest audience share of all Finnish TV channels when Finnish Broadcasting Company's YLE1 took the lead. The letters MTV stand for Mainos-TV , due to the channel getting its revenue from running commercials...
started broadcasting the youth music program
Jyrki in PALplus format on 1997-08-18, but the experiment ended when the program ended some four years later. Now both MTV and the public broadcaster YLE have switched to digital TV technology.
Greece
In
GreeceGreece , officially the Hellenic Republic , is a country in southeastern Europe, situated on the southern end of the Balkan Peninsula....
, there are still sporadic PALplus broadcasts, on the national television (E.R.T. - Hellenic Radio Television). Through the '90s there were few attempts from commercial broadcasters to adopt the system, but they all failed to gain popularity.
Because of the nature of ERT's
broadcastingBroadcasting is the distribution of audio and/or video signals which transmit programs to an audience. The audience may be the general public or a relatively large sub-audience, such as children or young adults....
equipment,
events and documentaries shot by ERT in PALPlus are still broadcast as such, as they leave control room to be distributed.
However, PALplus reaching audiences is a different story.
PALplus is not preserved when content is distributed via
NOVANOVA Greece is a Greek digital satellite pay TV platform owned by Multichoice Hellas. It was launched on December 1999 and is the first and only pay TV satellite service in Greece....
, due to heavy MPEG
encodingEncoding is the process of transforming information from one format into another. The opposite operation is called decoding. This is often used in many digital devicesThere are a number of more specific meanings that apply in certain contexts:...
since
WSS signalingIn television technology, widescreen signaling is a digital stream embedded in the TV signal describing qualities of the broadcast, in particular the intended aspect ratio of the image...
and additional information embedded in PALplus are seriously degraded to the extent that renders them no longer decodable.
As some of the repeaters of ERT's channels are fed via
OTEOTE is the national telecommunications provider of Greece.Standing for Hellenic Telecommunication Organization , OTE is the incumbent telecommunications operator of Greece.-History:...
(Greek public telecom provider) in uncompressed form over terrestrial links, and others are fed via
NOVANOVA Greece is a Greek digital satellite pay TV platform owned by Multichoice Hellas. It was launched on December 1999 and is the first and only pay TV satellite service in Greece....
(Greece's only satellite platform) it depends on each repeater's feed source whether the content terrestrially broadcast (VHF - UHF) is PALplus or not.
Spain
In
SpainSpain , officially the Kingdom of Spain , is a country located in southwestern Europe on the Iberian Peninsula.
[The Spanish constitution does not establish any official denomination of the country, even though España , Estado español and Nación española are used interchangeably...]
, the Catalan public television,
TV3TV3 is the name of Catalonia's first public television channel. It belongs to Televisió de Catalunya , a subsidiary of the CCRTV. TV3 broadcasts programs only in Catalan, with an optional dual track in the original language for some foreign-language series and movies...
, trialed the PALplus format in the late 1990s, with a weekly broadcast of a film in this format. Other public regional stations (like Galicia's TVG) tested the format too, but after these trials the technology was dropped and 16:9 digital broadcasts were not introduced until 2007.
United Kingdom
In the
United KingdomThe United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of Ireland, and many small islands...
,
Channel 4Channel 4 is a UK public-service television broadcaster which began working on November 2, 1982. Although commercially self-funded, it is ultimately publicly owned; originally a subsidiary of the Independent Broadcasting Authority , the station owned now and operated by the Channel Four Television...
broadcast selected films as PALplus during the late 1990s. All of the six main broadcasters,
BBCThe British Broadcasting Corporation, usually referred to by its abbreviation as the "BBC", is the longest established and largest broadcaster in the world...
,
ITVITV is a public service network of British commercial television broadcasters, set up under the Independent Television Authority to provide competition to the BBC. ITV is the oldest commercial television network in the UK...
,
Channel 4Channel 4 is a UK public-service television broadcaster which began working on November 2, 1982. Although commercially self-funded, it is ultimately publicly owned; originally a subsidiary of the Independent Broadcasting Authority , the station owned now and operated by the Channel Four Television...
, Five,
SkyThe sky is the part of the atmosphere or of outer space visible from the surface of any astronomical object. It is difficult to define precisely for several reasons. During daylight, the sky of Earth has the appearance of a deep blue surface because of the air's scattering of sunlight. The sky is...
& VMTV (Virgin Media Television), now all broadcast in anamorphic widescreen on digital.
History
In the late 1980s a new broadcasting standard was created,
HD-MACHD-MAC was a proposed television standard by the European Commission in 1986 . It was an early attempt by the EEC to provide HDTV in Europe. It was a complex mix of analogue signal , multiplexed with digital sound...
, that was
HDTVHigh-definition television is a digital television broadcasting system with higher resolution than traditional television systems...
and 16:9 capable (up to 2048×1152 picture resolution), twice the number of available lines in PAL. As a transitional standard,
D2-MACD2-MAC was created to solve D-MAC's bandwidth problem on European cable systems.* D2-MAC uses half the data rate of D-MAC {10.125Mb/s}* D2-MAC has a reduced vision bandwidth, about 1/2 that of D-MAC....
was established. Like HD-MAC, it is 16:9 ready, but with the same number of lines that PAL uses. When D2-MAC failed due to being a incompatible system with existing sets, the PALplus norm was introduced as an attempt to create a compatible
widescreenA widescreen image is a film, computer or television image with a wider and shorter aspect ratio than the standard Academy frame developed during the classical Hollywood cinema era. Silent film was projected at a ratio of four units wide to three units tall, often expressed as 4:3 or 1.33:1...
EDTVEDtv is a comedy film directed by Ron Howard released in 1999. An adaptation of the French Canadian movie Louis 19, le roi des ondes , it stars Matthew McConaughey, Jenna Elfman, Woody Harrelson, Ellen DeGeneres, Martin Landau, Rob Reiner, Sally Kirkland, Elizabeth Hurley, Clint Howard and Dennis...
transmission format.
Initially, PALplus was the name of a strategy group founded in 1989 in order to develop an enhanced system for terrestrial transmission compatible with standard-PAL. In the beginning, the group consisted of the public broadcasting corporations of Germany (ARD and ZDF), Austria(ORF), Switzerland (SRG) and the United Kingdom (BBC and UKIB, United Kingdom Independent Broadcasters) together with the consumer electronics manufacturers Grundig, Nokia, Philips and Thomson. Sony as well as the Spanish and Portuguese broadcasters joined the group later on.
At the 1993 International Consumer Electronics Exhibition in Berlin, the first experimental PALplus broadcasts began.
In 1994 broadcasts began adopting the format and Nokia launched the first PALplus TV set in Germany.
In 1995 one of the four big Korean electronics manufacturers, Samsung, joined the PALplus consortium.
On January 1996, the PALplus board published the specifications of PALplus in order to support the further dissemination of this standard for wide-screen transmissions. After German broadcasters started to broadcast some of their programmes in PAL+, the PALplus board ended its work at the end of that same year.
At the beginning of 1998, PALplus programmes were broadcast on a regular basis in nine European countries, which made PALplus the mostly used standard for 16:9 transmissions in Europe.
Criticism
The decoding of a 16:9 picture in PALplus is very costly and requires the use of the two fields of the full picture. Because of this, only expensive TVs such as 100 Hz TV sets can decode the 16:9 mode of PALplus.
For all this, the takeup of PALplus has been marginal, and the future of this standard does not look very bright, since broadcasters are switching to
digital televisionDigital television is the sending and receiving of moving images and sound by discrete signals, in contrast to the analog signals used by analog TV.-Timeline:...
broadcasting (DVB).
See also
- HDTV
High-definition television is a digital television broadcasting system with higher resolution than traditional television systems...
- DVB
- PAL
PAL, short for Phase Alternating Line, is an analogue television encoding system used in broadcast television systems in large parts of the world. Other common analogue television systems are SECAM and NTSC. This page primarily discusses the colour encoding system...
- Broadcast television system
There are several broadcast television systems in use in the world today. An analogue television system includes several components: a set of technical parameters for the broadcast signal, a system for encoding color, and possibly a system for encoding multi-channel audio...
- Widescreen television
- Widescreen signaling
In television technology, widescreen signaling is a digital stream embedded in the TV signal describing qualities of the broadcast, in particular the intended aspect ratio of the image...
External links