Closed captioning (CC) and
subtitling are both processes of displaying text on a television, video screen, or other visual display to provide additional or interpretive information. Both are typically used as a
transcription of the audio portion of a program as it occurs (either
verbatim or in edited form), sometimes including descriptions of non-speech elements. Other uses have included providing a textual alternative language translation of a presentation's primary audio language that is usually burned-in (or "open") to the video and unselectable.
HTML5 defines subtitles as a "transcription or translation of the dialogue when sound is available but not understood" by the viewer (for example, dialogue in a foreign language) and captions as a "transcription or translation of the dialogue, sound effects, relevant musical cues, and other relevant audio information when sound is unavailable or not clearly audible" (for example, when audio is muted or the viewer is deaf or hard of hearing).
Terminology
The term ''closed'' indicates that the captions are not visible until activated by the viewer, usually via the
remote control
In electronics, a remote control (also known as a remote or clicker) is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such ...
or menu option. On the other hand, the terms ''open'', ''burned-in'', ''baked on'', ''hard-coded'', or simply ''hard'' indicate that the captions are visible to all viewers as they are embedded in the video.
In the United States and Canada, the terms ''
subtitles'' and ''captions'' have different meanings. ''Subtitles'' assume the viewer can hear but cannot understand the language or accent, or the speech is not entirely clear, so they transcribe only dialogue and some on-screen text. ''Captions'' aim to describe to the deaf and hard of hearing all significant audio content—spoken dialogue and non-speech information such as the identity of speakers and, occasionally, their manner of speaking—along with any significant
music or
sound effects using words or symbols. Also, the term ''closed caption'' has come to be used to also refer to the North American
EIA-608 encoding that is used with NTSC-compatible video.
The
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and ...
,
Ireland
Ireland ( ; ga, Éire ; Ulster-Scots: ) is an island in the North Atlantic Ocean, in north-western Europe. It is separated from Great Britain to its east by the North Channel, the Irish Sea, and St George's Channel. Ireland is the s ...
, and most other countries do not distinguish between subtitles and closed captions and use ''subtitles'' as the general term. The equivalent of ''captioning'' is usually referred to as ''subtitles for the hard of hearing''. Their presence is referenced on screen by notation which says "Subtitles", or previously "Subtitles 888" or just "888" (the latter two are in reference to the conventional
videotext channel for captions), which is why the term ''subtitle'' is also used to refer to the
Ceefax
Ceefax (, punning on "seeing facts") was the world's first teletext information service and a forerunner to the current BBC Red Button service. Ceefax was started by the BBC in 1974 and ended, after 38 years of broadcasting, at 23:32:19 BST ...
-based videotext encoding that is used with PAL-compatible video. The term ''subtitle'' has been replaced with ''caption'' in a number of markets—such as Australia and New Zealand—that purchase large amounts of imported US material, with much of that video having had the US CC logo already superimposed over the start of it. In New Zealand, broadcasters superimpose an ear logo with a line through it that represents subtitles for the hard of hearing, even though they are currently referred to as captions. In the UK, modern digital television services have subtitles for the majority of programs, so it is no longer necessary to highlight which have subtitling/captioning and which do not.
Remote control
In electronics, a remote control (also known as a remote or clicker) is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such ...
handsets for TVs, DVDs, and similar devices in most European markets often use "SUB" or "SUBTITLE" on the button used to control the display of subtitles/captions.
History
Open captioning
Regular open-captioned broadcasts began on
PBS's ''
The French Chef'' in 1972.
WGBH WGBH may refer to:
* WGBH Educational Foundation, based in Boston, Massachusetts, United States
** WGBH (FM), a public radio station at Boston, Massachusetts on 89.7 MHz owned by the WGBH Educational Foundation
** WGBH-TV
WGBH-TV (channel 2), ...
began open captioning of the programs ''
Zoom'', ''
ABC World News Tonight
''ABC World News Tonight'' (titled ''ABC World News Tonight with David Muir'' for its weeknight broadcasts since September 2014) is the flagship daily evening television news program of ABC News, the news division of the American Broadcasting ...
'', and ''
Once Upon a Classic
''Once Upon a Classic'' was an American television program hosted by Bill Bixby. The program aired on PBS from 1976 to 1980 as a production of WQED in Pittsburgh.
The episodes consisted of adaptations of such classic literature as ''A Connecticu ...
'' shortly thereafter.
Technical development of closed captioning
Closed captioning was first demonstrated in the United States at the First National Conference on Television for the Hearing Impaired in Nashville, Tennessee, in 1971.
A second demonstration of closed captioning was held at Gallaudet College (now
Gallaudet University) on February 15, 1972, where
ABC and the
National Bureau of Standards demonstrated closed captions embedded within a normal broadcast of ''
The Mod Squad''.
At the same time in the UK the BBC was demonstrating its Ceefax text based broadcast service which they were already using as a foundation to the development of a closed caption production system. They were working with Professor
Alan Newell from the University of Southampton who had been developing prototypes in the late 1960s.
The closed captioning system was successfully encoded and broadcast in 1973 with the cooperation of PBS station
WETA.
As a result of these tests, the FCC in 1976 set aside line 21 for the transmission of closed captions. PBS engineers then developed the caption editing consoles that would be used to caption prerecorded programs.
The
BBC in the UK was the first broadcaster to include closed captions (called subtitles in the UK) in 1979 based on the
Teletext framework for pre-recorded programming.
Real-time captioning, a process for captioning live broadcasts, was developed by the
National Captioning Institute in 1982.
In real-time captioning,
stenotype
A steno machine, stenotype machine, shorthand machine, stenograph or steno writer is a specialized chorded keyboard or typewriter used by stenographers for shorthand use. In order to pass the United States Registered Professional Reporter test, ...
operators who are able to type at speeds of over 225 words per minute provide captions for live television programs, allowing the viewer to see the captions within two to three seconds of the words being spoken.
Major US producers of captions are
WGBH-TV,
VITAC,
CaptionMax and the
National Captioning Institute. In the UK and
Australasia
Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologic ...
, Ai-Media,
Red Bee Media, itfc, and Independent Media Support are the major vendors.
Improvements in
speech recognition
Speech recognition is an interdisciplinary subfield of computer science and computational linguistics that develops methodologies and technologies that enable the recognition and translation of spoken language into text by computers with the ...
technology means that live captioning may be fully or partially automated.
BBC Sport
BBC Sport is the sports division of the BBC, providing national sports coverage for BBC television, radio and online. The BBC holds the television and radio UK broadcasting rights to several sports, broadcasting the sport live or alongside f ...
broadcasts use a "respeaker": a trained human who repeats the running commentary (with careful enunciation and some simplification and
markup) for input to the automated text generation system. This is generally reliable, though errors are not unknown.
Full-scale closed captioning
The National Captioning Institute was created in 1979 in order to get the cooperation of the commercial television networks.
The first use of regularly scheduled closed captioning on American television occurred on March 16, 1980.
Sears had developed and sold the Telecaption adapter, a decoding unit that could be connected to a standard television set. The first programs seen with captioning were a ''
Disney's Wonderful World'' presentation of the film ''
Son of Flubber'' on
NBC, an ''
ABC Sunday Night Movie'' airing of ''
Semi-Tough'', and ''
Masterpiece Theatre'' on
PBS.
Since 2010 BBC provides a 100% broadcast captioning service across all 7 of its main broadcast channels
BBC One,
BBC Two,
BBC Three,
BBC Four,
CBBC
CBBC (initialised as Children's BBC and also known as the CBBC Channel) is a British free-to-air public broadcast children's television channel owned and operated by the BBC. It is also the brand used for all BBC content for children aged 7–16 ...
,
Cbeebies and
BBC News (TV channel).
BBC iPlayer launched in 2008 as the first captioned
Video on demand
Video on demand (VOD) is a media distribution system that allows users to access videos without a traditional video playback device and the constraints of a typical static broadcasting schedule. In the 20th century, broadcasting in the form of ...
service from a major broadcaster meeting comparable levels of captioning as those provided on its broadcast channels.
Legislative development in the U.S.
Until the passage of the Television Decoder Circuitry Act of 1990, television captioning was performed by a set-top box manufactured by Sanyo Electric and marketed by the National Captioning Institute (NCI). (At that time a set-top decoder cost about as much as a TV set itself, approximately $200.) Through discussions with the manufacturer it was established that the appropriate circuitry integrated into the television set would be less expensive than the stand-alone box, and Ronald May, then a Sanyo employee, provided the expert witness testimony on behalf of Sanyo and Gallaudet University in support of the passage of the bill. On January 23, 1991, the
Television Decoder Circuitry Act of 1990 was passed by Congress.
This Act gave the
Federal Communications Commission (FCC) power to enact rules on the implementation of closed captioning. This Act required all analog television receivers with screens of at least 13 inches or greater, either sold or manufactured, to have the ability to display closed captioning by July 1, 1993.
Also, in 1990, the
Americans with Disabilities Act (ADA) was passed to ensure equal opportunity for persons with disabilities.
The ADA prohibits discrimination against persons with disabilities in public accommodations or commercial facilities. Title III of the ADA requires that public facilities—such as hospitals, bars, shopping centers and museums (but not movie theaters)—provide access to verbal information on televisions, films or slide shows.
The Federal Communications Commission requires all providers of programs to caption material which has audio in English or Spanish, with certain exceptions specified in Section 79.1(d) of the commission's rules. These exceptions apply to new networks; programs in languages other than English or Spanish; networks having to spend over 2% of income on captioning; networks having less than US$3,000,000 in revenue; and certain local programs; among other exceptions. Those who are not covered by the exceptions may apply for a hardship waiver.
The
Telecommunications Act of 1996 expanded on the Decoder Circuitry Act to place the same requirements on
digital television receivers by July 1, 2002. All TV programming distributors in the U.S. are required to provide closed captions for Spanish-language video programming as of January 1, 2010.
A bill, H.R. 3101, the Twenty-First Century Communications and Video Accessibility Act of 2010, was passed by the United States House of Representatives in July 2010. A similar bill, S. 3304, with the same name, was passed by the United States Senate on August 5, 2010, by the House of Representatives on September 28, 2010, and was signed by President
Barack Obama
Barack Hussein Obama II ( ; born August 4, 1961) is an American politician who served as the 44th president of the United States from 2009 to 2017. A member of the Democratic Party (United States), Democratic Party, Obama was the first Af ...
on October 8, 2010. The Act requires, in part, for
ATSC-decoding set-top box remotes to have a button to turn on or off the closed captioning in the output signal. It also requires broadcasters to provide captioning for television programs redistributed on the Internet.
On February 20, 2014, the FCC unanimously approved the implementation of quality standards for closed captioning, addressing accuracy, timing, completeness, and placement. This is the first time the FCC has addressed quality issues in captions.
In 2015, a law was passed in Hawaii requiring two screenings a week of each movie with captions on the screen. In 2022 a law took effect in New York City requiring movie theaters to offer captions on the screen for up to four showtimes per movie each week, including weekends and Friday nights.
Some state and local governments (including
Boston, Massachusetts;
Portland, Oregon
Portland (, ) is a port city in the Pacific Northwest and the largest city in the U.S. state of Oregon. Situated at the confluence of the Willamette and Columbia rivers, Portland is the county seat of Multnomah County, the most populous ...
;
Rochester, New York
Rochester () is a City (New York), city in the U.S. state of New York (state), New York, the county seat, seat of Monroe County, New York, Monroe County, and the fourth-most populous in the state after New York City, Buffalo, New York, Buffalo, ...
; and
Washington state) require closed captioning to be activated on TVs in public places at all times, even if no one has requested it.
Philippines
As amended by RA 10905, all TV networks in the Philippines are required to give CC. As of 2018, the three major TV networks in the country are currently testing the closed captioning system on their transmissions.
ABS-CBN added CC in their daily
3 O'Clock Habit in the afternoon.
5 started implementing CCs on their live noon and nightly news programs.
GMA was once started broadcasting nightly and late night news programs, but then they stopped adding CCs lately. Only select
Korean drama and local or foreign movies, ''Biyahe ni Drew'' (English: ''Drew's Explorations'') and ''Idol sa Kusina'' (English: ''Kitchen Idol'') are the programs and shows that they air with proper closed captioning.
Closed captioning in some Filipino films either to be "included" if film production companies have a bias on having impact on their viewing experience for those who did not understand the language. Since 2016, all Filipino-Language Films and also on some Streaming Services like iWant had included their English Subtitles in some showing on films. The law regarding that was passed by Gerald Anthony Gullas Jr., a lawmaker from Cebu City, who had implemented the regulations on standardizing both official languages of the Philippines, as the people had not fluently mastered their English vocabulary.
Legislative development in Australia
The government of Australia provided
seed funding in 1981 for the establishment of the Australian Caption Centre (ACC) and the purchase of equipment. Captioning by the ACC commenced in 1982 and a further grant from the Australian government enabled the ACC to achieve and maintain financial self-sufficiency. The ACC, now known as
Media Access Australia
Media Access Australia (M.A.A.) strives for accessibility and inclusion through technology and is a not-for-profit organization located in Australia dedicated to increasing access to websites and digital media for people with disabilities. This i ...
, sold its commercial captioning division to
Red Bee Media in December 2005. Red Bee Media continues to provide captioning services in Australia today.
Funding development in New Zealand
In 1981,
TVNZ held a
telethon to raise funds for Teletext-encoding equipment used for the creation and editing of text-based broadcast services for the deaf. The service came into use in 1984 with caption creation and importing paid for as part of the public broadcasting fee until the creation of the
NZ on Air taxpayer fund, which is used to provide captioning for
NZ On Air content, TVNZ news shows and conversion of
EIA-608 US captions to the preferred
EBU STL format for only
TVNZ 1,
TV 2 and
TV 3 with archived captions available to
FOUR
4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5. It is the smallest semiprime and composite number, and is considered unlucky in many East Asian cultures.
In mathematics
Four is the smallest ...
and select
Sky programming. During the second half of 2012,
TV3 and
FOUR
4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5. It is the smallest semiprime and composite number, and is considered unlucky in many East Asian cultures.
In mathematics
Four is the smallest ...
began providing non-Teletext DVB image-based captions on their HD service and used the same format on the satellite service, which has since caused major timing issues in relation to server load and the loss of captions from most SD DVB-S receivers, such as the ones Sky Television provides their customers. As of April 2, 2013, only the Teletext page 801 caption service will remain in use with the informational Teletext non-caption content being discontinued.
Application
Closed captions were created for
deaf and
hard of hearing individuals to assist in comprehension. They can also be used as a tool by those learning to read, learning to speak a non-native language, or in an environment where the audio is difficult to hear or is intentionally muted. Captions can also be used by viewers who simply wish to read a transcript along with the program audio.
In the United States, the
National Captioning Institute noted that
English as a foreign or second language (ESL) learners were the largest group buying decoders in the late 1980s and early 1990s before built-in decoders became a standard feature of US television sets. This suggested that the largest audience of closed captioning was people whose native language was not English. In the United Kingdom, of 7.5 million people using TV subtitles (closed captioning), 6 million have no hearing impairment.
Closed captions are also used in public environments, such as bars and restaurants, where patrons may not be able to hear over the background noise, or where multiple televisions are displaying different programs. In addition, online videos may be treated through digital processing of their audio content by various robotic algorithms (robots). Multiple chains of errors are the result. When a video is truly and accurately transcribed, then the closed-captioning publication serves a useful purpose, and the content is available for search engines to index and make available to users on the internet.
Some television sets can be set to automatically turn captioning on when the volume is muted.
Television and video
For ''live'' programs, spoken words comprising the television program's
soundtrack
A soundtrack is recorded music accompanying and synchronised to the images of a motion picture, drama, book, television program, radio program, or video game; a commercially released soundtrack album of music as featured in the soundtrac ...
are transcribed by a human operator (a
speech-to-text reporter
A speech-to-text reporter (STTR), also known as a captioner, is a person who listens to what is being said and inputs it, word for word (verbatim), using an electronic shorthand keyboard, speech recognition software, or a CAT (Computer Aided Tra ...
) using
stenotype
A steno machine, stenotype machine, shorthand machine, stenograph or steno writer is a specialized chorded keyboard or typewriter used by stenographers for shorthand use. In order to pass the United States Registered Professional Reporter test, ...
or
stenomask type of machines, whose phonetic output is instantly translated into text by a computer and displayed on the screen. This technique was developed in the 1970s as an initiative of the
BBC's
Ceefax
Ceefax (, punning on "seeing facts") was the world's first teletext information service and a forerunner to the current BBC Red Button service. Ceefax was started by the BBC in 1974 and ended, after 38 years of broadcasting, at 23:32:19 BST ...
teletext service. In collaboration with the BBC, a university student took on the research project of writing the first phonetics-to-text conversion program for this purpose. Sometimes, the captions of live broadcasts, like news bulletins, sports events, live entertainment shows, and other live shows, fall behind by a few seconds. This delay is because the machine does not know what the person is going to say next, so after the person on the show says the sentence, the captions appear. Automatic computer speech recognition works well when trained to recognize a single voice, and so since 2003, the BBC does live subtitling by having someone re-speak what is being broadcast. Live captioning is also a form of
real-time text. Meanwhile, sport events on ESPN are using
court reporters, using a special (steno) keyboard and individually constructed "dictionaries."
In some cases, the transcript is available beforehand, and captions are simply displayed during the program after being edited. For programs that have a mix of pre-prepared and live content, such as
news bulletin
Breaking news, interchangeably termed late-breaking news and also known as a special report or special coverage or news flash, is a current issue that broadcasters feel warrants the interruption of scheduled programming or current news in orde ...
s, a combination of techniques is used.
For prerecorded programs, commercials, and home videos, audio is transcribed and captions are prepared, positioned, and timed in advance.
For all types of
NTSC
The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...
programming, captions are "encoded" into
line 21 of the
vertical blanking interval - a part of the TV picture that sits just above the visible portion and is usually unseen. For
ATSC (
digital television) programming, three streams are encoded in the video: two are backward compatible "line 21" captions, and the third is a set of up to 63 additional caption streams encoded in
EIA-708 format.
[ - ATSC Closed Captioning FAQ]
cached copy
Captioning is modulated and stored differently in
PAL and
SECAM 625 line 25 frame countries, where
teletext is used rather than in
EIA-608, but the methods of preparation and the line 21 field used are similar. For home
Betamax and
VHS videotapes, a shift down of this line 21 field must be done due to the greater number of VBI lines used in 625 line PAL countries, though only a small minority of European PAL VHS machines support this (or any) format for closed caption recording. Like all teletext fields, teletext captions can't be stored by a standard 625 line VHS recorder (due to the lack of field shifting support); they are available on all professional
S-VHS recordings due to all fields being recorded. Recorded Teletext caption fields also suffer from a higher number of caption errors due to increased number of bits and a low
SNR, especially on low-bandwidth VHS. This is why Teletext captions used to be stored separately on floppy disk to the analogue master tape. DVDs have their own system for subtitles and captions, which are digitally inserted in the data stream and decoded on playback into video.
For older televisions, a set-top box or other decoder is usually required. In the US, since the passage of the Television Decoder Circuitry Act, manufacturers of most television receivers sold have been required to include closed captioning display capability. High-definition TV sets, receivers, and
tuner cards are also covered, though the technical specifications are different (high-definition display screens, as opposed to high-definition TVs, may lack captioning). Canada has no similar law but receives the same sets as the US in most cases.
During transmission, single byte errors can be replaced by a white space which can appear at the beginning of the program. More byte errors during EIA-608 transmission can affect the screen momentarily, by defaulting to a real-time mode such as the "roll up" style, type random letters on screen, and then revert to normal. Uncorrectable byte errors within the teletext page header will cause whole captions to be dropped. EIA-608, due to using only two characters per video frame, sends these captions ahead of time storing them in a second buffer awaiting a command to display them; Teletext sends these in real-time.
The use of capitalization varies among caption providers. Most caption providers capitalize all words while others such as WGBH and non-US providers prefer to use mixed-case letters.
There are two main styles of line 21 closed captioning:
* Roll-up or scroll-up or paint-on or scrolling: Real-time words sent in paint-on or scrolling mode appear from left to right, up to one line at a time; when a line is filled in roll-up mode, the whole line scrolls up to make way for a new line, and the line on top is erased. The lines usually appear at the bottom of the screen, but can actually be placed on any of the 14 screen rows to avoid covering graphics or action. This method is used when captioning video in real-time such as for live events, where a sequential word-by-word captioning process is needed or a pre-made intermediary file isn't available. This method is signaled on
EIA-608 by a two-byte caption command or in Teletext by replacing rows for a roll-up effect and duplicating rows for a paint-on effect. This allows for real-time caption line editing.
* Pop-on or pop-up or block: A caption appears on any of the 14 screen rows as a complete sentence, which can be followed by additional captions. This method is used when captions come from an intermediary file (such as the Scenarist or EBU STL file formats) for pre-taped television and film programming, commonly produced at captioning facilities. This method of captioning can be aided by digital scripts or voice recognition software, and if used for live events, would require a video delay to avoid a large delay in the captions' appearance on-screen, which occurs with Teletext-encoded live subtitles.
Caption formatting
TVNZ Access Services and Red Bee Media for BBC and Australia example:
I got the machine ready.
ENGINE STARTING
(speeding away)
UK IMS for ITV and Sky example:
(man) I got the machine ready. (engine starting)
US WGBH Access Services example:
MAN: I got the machine ready. (engine starting)
US
National Captioning Institute example:
- I GOT THE MACHINE READY.
US other provider example:
I GOT THE MACHINE READY.
ngine starting
US in-house real-time roll-up example:
>> Man: I GOT THE MACHINE READY.
ngine starting
Non-US in-house real-time roll-up example:
MAN: I got the machine ready.
(ENGINE STARTING)
US
CaptionMax example:
ANI got the machine ready.
ngine starting
Syntax
For real-time captioning done outside of captioning facilities, the following syntax is used:
* '>>' (two prefixed
greater-than signs) indicates a change in single speaker.
** Sometimes appended with the speaker's name in alternate case, followed by a
colon.
* '>>>' (three prefixed greater-than signs) indicates a change in news story or multiple speakers.
Styles of syntax that are used by various captioning producers:
* Capitals indicate main on-screen dialogue and the name of the speaker.
** Legacy
EIA-608 home caption decoder fonts had no
descender
In typography and handwriting, a descender is the portion of a letter that extends below the baseline of a font.
For example, in the letter ''y'', the descender is the "tail", or that portion of the diagonal line which lies below the ''v' ...
s on lowercase letters.
** Outside North America, capitals with background coloration indicate a song title or sound effect description.
** Outside North America, capitals with black or no background coloration indicates when a word is stressed or emphasized.
* Descenders indicate background sound description and
off-screen
The terms offscreen, off camera, and offstage refer to fictional events in theatre, television, or film which are not seen on stage or in frame, but are merely heard by the audience, or described (or implied) by the characters or narrator. Of ...
dialogue.
** Most modern caption producers, such as
WGBH-TV, use
mixed case
Capitalization (American English) or capitalisation (British English) is writing a word with its first letter as a capital letter (uppercase letter) and the remaining letters in lower case, in writing systems with a case distinction. The term a ...
for both on-screen and
off-screen
The terms offscreen, off camera, and offstage refer to fictional events in theatre, television, or film which are not seen on stage or in frame, but are merely heard by the audience, or described (or implied) by the characters or narrator. Of ...
dialogue.
* '-' (a prefixed dash) indicates a change in single speaker (used by
CaptionMax).
* Words in
italics
In typography, italic type is a cursive font based on a stylised form of calligraphic handwriting. Owing to the influence from calligraphy, italics normally slant slightly to the right. Italics are a way to emphasise key points in a printed t ...
indicate when a word is stressed or emphasized and when real world names are quoted.
** Italics and
bold type are only supported by
EIA-608.
** Some North American providers use this for
narrated dialogue.
** Some providers use this for
off-screen
The terms offscreen, off camera, and offstage refer to fictional events in theatre, television, or film which are not seen on stage or in frame, but are merely heard by the audience, or described (or implied) by the characters or narrator. Of ...
dialogue.
** Italics are also applied when a word is spoken in a foreign language.
* Text coloration indicates captioning credits and sponsorship.
** Used by
music video
A music video is a video of variable duration, that integrates a music song or a music album with imagery that is produced for promotional or musical artistic purposes. Modern music videos are primarily made and used as a music marketing devic ...
s in the past, but generally has declined due to system incompatibilities.
** In Ceefax/Teletext countries, it indicates a change in single speaker in place of '>>'.
** Some Teletext countries use coloration to indicate when a word is stressed or emphasized.
** Coloration is limited to white, green, blue, cyan, red, yellow and magenta.
** UK order of use for text is
white
White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White ...
,
green
Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 nm. In subtractive color systems, used in painting and color printing, it is created by a combin ...
,
cyan,
yellow
Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In th ...
; and backgrounds is
black
Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white ha ...
,
red,
blue
Blue is one of the three primary colours in the RYB colour model (traditional colour theory), as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The eye perceives blue when ...
,
magenta,
white
White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White ...
.
** US order of use for text is
white
White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White ...
,
yellow
Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In th ...
,
cyan,
green
Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 nm. In subtractive color systems, used in painting and color printing, it is created by a combin ...
; and backgrounds is
black
Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white ha ...
,
blue
Blue is one of the three primary colours in the RYB colour model (traditional colour theory), as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The eye perceives blue when ...
,
red,
magenta, white.
*
Square brackets
A bracket is either of two tall fore- or back-facing punctuation marks commonly used to isolate a segment of text or data from its surroundings. Typically deployed in symmetric pairs, an individual bracket may be identified as a 'left' or 'r ...
or
parentheses indicate a song title or sound effect description.
*
Parentheses indicate speaker's vocal pitch e.g., (man), (woman), (boy) or (girl).
** Outside North America,
parentheses indicate a silent on-screen action.
* A pair of
eighth notes is used to bracket a line of
lyrics to indicate singing.
** A pair of eighth notes on a line of no text are used during a section of instrumental music.
** Outside North America, a single
number sign is used on a line of
lyrics to indicate singing.
** An additional musical notation character is appended to the end of the last line of lyrics to indicate the song's end.
** As the symbol is unsupported by
Ceefax
Ceefax (, punning on "seeing facts") was the world's first teletext information service and a forerunner to the current BBC Red Button service. Ceefax was started by the BBC in 1974 and ended, after 38 years of broadcasting, at 23:32:19 BST ...
/
Teletext, a
number sign - which resembles a musical
sharp
Sharp or SHARP may refer to:
Acronyms
* SHARP (helmet ratings) (Safety Helmet Assessment and Rating Programme), a British motorcycle helmet safety rating scheme
* Self Help Addiction Recovery Program, a charitable organisation founded in 199 ...
- is substituted.
Technical aspects
There were many shortcomings in the original Line 21 specification from a
typographic
Typography is the art and technique of typesetting, arranging type to make written language legibility, legible, readability, readable and beauty, appealing when displayed. The arrangement of type involves selecting typefaces, Point (typogra ...
standpoint, since, for example, it lacked many of the characters required for captioning in languages other than English. Since that time, the core Line 21 character set has been expanded to include quite a few more characters, handling most requirements for languages common in North and South America such as
French
French (french: français(e), link=no) may refer to:
* Something of, from, or related to France
** French language, which originated in France, and its various dialects and accents
** French people, a nation and ethnic group identified with Franc ...
,
Spanish, and
Portuguese, though those extended characters are not required in all decoders and are thus unreliable in everyday use. The problem has been almost eliminated with a market specific full set of Western European characters and a private adopted
Norpak extension for
South Korean and
Japanese markets. The full
EIA-708 standard for digital television has worldwide character set support, but there has been little use of it due to
EBU Teletext dominating
DVB
Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) o ...
countries, which has its own extended character sets.
Captions are often edited to make them easier to read and to reduce the amount of text displayed onscreen. This editing can be very minor, with only a few occasional unimportant missed lines, to severe, where virtually every line spoken by the actors is condensed. The measure used to guide this editing is words per minute, commonly varying from 180 to 300, depending on the type of program. Offensive words are also captioned, but if the program is censored for TV broadcast, the broadcaster might not have arranged for the captioning to be edited or censored also. The "TV Guardian", a television
set-top box
A set-top box (STB), also colloquially known as a cable box and historically television decoder, is an information appliance device that generally contains a TV-tuner input and displays output to a television set and an external source of s ...
, is available to parents who wish to censor offensive language of programs—the video signal is fed into the box and if it detects an offensive word in the captioning, the audio signal is bleeped or muted for that period of time.
Caption channels
The Line 21 data stream can consist of data from several data channels
multiplexed together. Odd field 1 can have four data channels: two separate synchronized captions (CC1, CC2) with caption-related text, such as website
URLs (T1, T2). Even field 2 can have five additional data channels: two separate synchronized captions (CC3, CC4) with caption related text (T3, T4), and
Extended Data Services Extended Data Services (now XDS, previously EDS), is an American standard classified under Electronic Industries Alliance standard (XDS) for Now/Next
EPG details. XDS data structure is defined in CEA-608.
As CC1 and CC2 share bandwidth, if there is a lot of data in CC1, there will be little room for CC2 data and is generally only used for the primary audio captions. Similarly, CC3 and CC4 share the second even field of line 21. Since some early caption decoders supported only single field decoding of CC1 and CC2, captions for
SAP in a second language were often placed in CC2. This led to bandwidth problems, and the U.S.
Federal Communications Commission (FCC) recommendation is that bilingual programming should have the second caption language in CC3. Many Spanish television networks such as
Univision and
Telemundo, for example, provides
English subtitles
Subtitles and captions are lines of dialogue or other text displayed at the bottom of the screen in films, television programs, video games or other visual media. They can be transcriptions of the screenplay, translations of it, or informati ...
for many of its
Spanish programs in CC3.
Canadian
Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...
broadcasters use CC3 for French translated SAPs, which is also a similar practice in South Korea and Japan.
Ceefax and Teletext can have a larger number of captions for other languages due to the use of multiple VBI lines. However, only
European countries
The list below includes all entities falling even partially under any of the various common definitions of Europe, geographical or political. Fifty generally recognised sovereign states, Kosovo with limited, but substantial, international rec ...
used a second subtitle page for second language audio tracks where either the
NICAM dual mono or
Zweikanalton were used.
Digital television interoperability issues
The US
ATSC digital television system originally specified two different kinds of ''closed captioning'' datastream standards: the original analog-compatible (available by
Line 21) and the more modern digital-only
CEA-708 formats are delivered within the video stream.
The
US FCC mandates that broadcasters deliver (and generate, if necessary) both datastream formats with the
CEA-708 format merely a conversion of the Line 21 format.
The
Canadian
Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...
CRTC has not mandated that broadcasters either broadcast both datastream formats or exclusively in one format. Most broadcasters and networks to avoid large conversion cost outlays just provide
EIA-608 captions along with a transcoded
CEA-708 version encapsulated within
CEA-708 packets.
Incompatibility issues with digital TV
Many viewers find that when they acquire a
digital television or
set-top box
A set-top box (STB), also colloquially known as a cable box and historically television decoder, is an information appliance device that generally contains a TV-tuner input and displays output to a television set and an external source of s ...
they are unable to view closed caption (CC) information, even though the broadcaster is sending it and the
TV is able to display it.
Originally, CC information was included in the picture ("line 21") via a
composite video input, but there is no equivalent capability in digital video interconnects (such as
DVI
Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a comp ...
and
HDMI) between the display and a "source". A "source", in this case, can be a
DVD player or a
terrestrial or cable digital television receiver. When CC information is encoded in the
MPEG-2 data stream, only the device that decodes the
MPEG-2 data (a source) has access to the ''closed caption'' information; there is no standard for transmitting the CC information to a display monitor separately. Thus, if there is CC information, the source device needs to overlay the CC information on the picture prior to transmitting to the display over the interconnect's video output.
The responsibility of decoding the CC information and overlaying onto the visible video image has been taken away from the TV display and put into the "source" of DVI and HDMI digital video interconnects. Because the TV handles "mute" and, when using
DVI
Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a comp ...
and
HDMI, a different device handles turning on and off CC, this means the "captions come on automatically when the
TV is muted" feature no longer works. That source device—such as a
DVD player or
set-top box
A set-top box (STB), also colloquially known as a cable box and historically television decoder, is an information appliance device that generally contains a TV-tuner input and displays output to a television set and an external source of s ...
—must "burn" the image of the CC text into the picture data carried by the
HDMI or
DVI
Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a comp ...
cable; there's no other way for the CC text to be carried over the
HDMI or
DVI
Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a comp ...
cable.
Many source devices do not have the ability to overlay CC information, for controlling the CC overlay can be complicated. For example, the
Motorola
Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois, United States. After having lost $4.3 billion from 2007 to 2009, the company split into two independent public companies, Motorola ...
DCT-5xxx and -6xxx cable set-top receivers have the ability to decode CC information located on the
MPEG-2 stream and overlay it on the picture, but turning CC on and off requires turning off the unit and going into a special setup menu (it is not on the standard configuration menu and it cannot be controlled using the remote). Historically,
DVD players
A DVD player is a device that plays DVDs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. Some DVD players will also play audio CDs. DVD players are connected to a television to w ...
,
VCRs and set-top tuners did not need to do this overlaying, since they simply passed this information on to the TV, and they are not mandated to perform this overlaying.
Many modern digital television receivers can be directly connected to cables, but often cannot receive scrambled channels that the user is paying for. Thus, the lack of a standard way of sending CC information between components, along with the lack of a mandate to add this information to a picture, results in CC being unavailable to many hard-of-hearing and deaf users.
The
EBU Ceefax
Ceefax (, punning on "seeing facts") was the world's first teletext information service and a forerunner to the current BBC Red Button service. Ceefax was started by the BBC in 1974 and ended, after 38 years of broadcasting, at 23:32:19 BST ...
-based teletext systems are the source for closed captioning signals, thus when teletext is embedded into
DVB-T or
DVB-S the closed captioning signal is included. However, for DVB-T and DVB-S, it is not necessary for a teletext page signal to also be present (
ITV1, for example, does not carry analogue teletext signals on
Sky Digital, but does carry the embedded version, accessible from the "Services" menu of the receiver, or more recently by turning them off/on from a mini menu accessible from the "help" button).
The
BBC's #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
Subtitle (Captioning) Editorial Guidelines were born out of the capabilities of
but are now used by multiple European broadcasters as the editorial and design best practice guide
). This made
connected TVs incapable of decoding the captions on their own. Also, these
and obscure the picture more than the more modern, partially transparent backgrounds.
specification provides for dramatically improved ''captioning''
* An enhanced character set with more
and non-Latin letters, and more special symbols
* Viewer-adjustable text size (called the "caption volume control" in the specification), allowing individuals to adjust their TVs to display small, normal, or large captions
* More text and background colors, including both transparent and translucent backgrounds to optionally replace the big
ed text rather than the letters on a solid background
* More text fonts, including
* More language channels, to allow the encoding of more independent caption streams
As of 2009, most closed captioning for digital television environments is done using tools designed for analog captioning (working to the
specification). The captions are then run through transcoders made by companies lik
to the digital format. This means that none of the
.
NTSC DVDs may carry closed captions in data packets of the MPEG-2 video streams inside of the Video-TS folder. Once played out of the analog outputs of a set top DVD player, the caption data is converted to the Line 21 format. They are output by the player to the
) for a connected TV's built-in decoder or a set-top decoder as usual. They can not be output on
signal on line 21. (Actually, regardless of this, if the DVD player is in interlaced rather than progressive mode, closed captioning ''will'' be displayed on the TV over component video input if the TV captioning is turned on and set to CC1.) When viewed on a personal computer, caption data can be viewed by software that can read and decode the caption data packets in the MPEG-2 streams of the DVD-Video disc.
) in Vista supported only closed caption channels 1 and 2 (not 3 or 4).
does not have the ability to read and decode Line 21 caption data which are recorded on a DVD made from an over-the-air broadcast. It can display some movie DVD captions.
In addition to Line 21 closed captions, video DVDs may also carry subtitles, which generally rendered from the
captions as a bitmap overlay that can be turned on and off via a set top DVD player or DVD player software, just like the textual captions. This type of captioning is usually carried in a subtitle track labeled either "English for the hearing impaired" or, more recently, "SDH" (subtitled for the deaf and Hard of hearing). Many popular Hollywood DVD-Videos can carry both subtitles and closed captions (e.g. ''
'' DVD by Columbia Pictures). On some DVDs, the Line 21 captions may contain the same text as the subtitles; on others, only the Line 21 captions include the additional non-speech information (even sometimes song lyrics) needed for deaf and hard-of-hearing viewers. European Region 2 DVDs do not carry Line 21 captions, and instead list the subtitle languages available-English is often listed twice, one as the representation of the dialogue alone, and a second subtitle set which carries additional information for the deaf and hard-of-hearing audience. (Many deaf/ subtitle files on DVDs are reworkings of original teletext subtitle files.)
(HDMI) specifications that was only extended for synchronized digital audio replacing older analog standards, such as
. Both Blu-ray and DVD can use either PNG bitmap subtitles or 'advanced subtitles' to carry SDH type subtitling, the latter being an XML-based textual format which includes font, styling and positioning information as well as a unicode representation of the text. Advanced subtitling can also include additional media accessibility features such as "descriptive audio".
There are several competing technologies used to provide captioning for movies in theaters. Cinema captioning falls into the categories of open and closed. The definition of "closed" captioning in this context is different from television, as it refers to any technology that allows as few as one member of the audience to view the captions.
Open captioning in a film theater can be accomplished through burned-in captions, projected text or
s, or (rarely) a display located above or below the movie screen. Typically, this display is a large LED sign. In a digital theater, open caption display capability is built into the digital projector. Closed caption capability is also available, with the ability for 3rd-party closed caption devices to plug into the digital cinema server.
Probably the best known closed captioning option for film theaters is the
. Upon entering the theater, viewers requiring captions are given a panel of flat translucent glass or plastic on a gooseneck stalk, which can be mounted in front of the viewer's seat. In the back of the theater is an
display that shows the captions in mirror image. The panel reflects captions for the viewer but is nearly invisible to surrounding patrons. The panel can be positioned so that the viewer watches the movie through the panel, and captions appear either on or near the movie image. A company called Cinematic Captioning Systems has a similar reflective system called Bounce Back. A major problem for distributors has been that these systems are each proprietary, and require separate distributions to the theater to enable them to work. Proprietary systems also incur license fees.
For film projection systems,
standard, has created a digital captioning device called the DTS-CSS (Cinema Subtitling System). It is a combination of a laser projector which places the captioning (words, sounds) anywhere on the screen and a thin playback device with a
that holds many languages. If the Rear Window Captioning System is used, the DTS-CSS player is also required for sending caption text to the Rear Window sign located in the rear of the theater.
Special effort has been made to build accessibility features into digital projection systems (see
). Through
, standards now exist that dictate how open and closed captions, as well as hearing-impaired and visually impaired narrative audio, are packaged with the rest of the digital movie. This eliminates the proprietary caption distributions required for film, and the associated royalties. SMPTE has also standardized the communication of closed caption content between the digital cinema server and 3rd-party closed caption systems (the CSP/RPL protocol). As a result, new, competitive closed caption systems for digital cinema are now emerging that will work with any standards-compliant digital cinema server. These newer closed caption devices include cupholder-mounted electronic displays and wireless glasses which display caption text in front of the wearer's eyes. Bridge devices are also available to enable the use of Rear Window systems. As of mid-2010, the remaining challenge to the wide introduction of accessibility in digital cinema is the industry-wide transition to SMPTE DCP, the standardized packaging method for very high quality, secure distribution of digital movies.
Captioning systems have also been adopted by most major league and high-profile college
LED boards. These screens display captions of the
announcer and other spoken content, such as those contained within in-game segments, public service announcements, and lyrics of songs played in-stadium. In some facilities, these systems were added as a result of discrimination lawsuits. Following a lawsuit under the
added caption screens in 2006.
Some stadiums utilize on-site captioners while others outsource them to external providers who caption remotely.
s became a problem in the 1990s as games began to commonly feature voice tracks, which in some cases contained information which the player needed in order to know how to progress in the game. Closed captioning of video games is becoming more common. One of the first video game companies to feature closed captioning was
''. Infocom also offered ''
'' in 1997. Many games since then have at least offered subtitles for spoken dialog during
s, and many include significant in-game dialog and sound effects in the captions as well; for example, with subtitles turned on in the ''
'' series of stealth games, not only are subtitles available during cut scenes, but any dialog spoken during real-time gameplay will be captioned as well, allowing players who can't hear the dialog to know what enemy guards are saying and when the main character has been detected. Also, in many of developer
''), when closed captions are activated, dialog and nearly all sound effects either made by the player or from other sources (e.g. gunfire, explosions) will be captioned.
Video games don't offer Line 21 captioning, decoded and displayed by the television itself but rather a built-in subtitle display, more akin to that of a DVD. The game systems themselves have no role in the captioning either; each game must have its subtitle display programmed individually.
Reid Kimball, a game designer who is hearing impaired, is attempting to educate game developers about closed captioning for games. Reid started th