Editing Closed captioning (section)

=== DVDs and Blu-ray Discs ===
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.<ref>{{cite web|url=https://www.dvddemystified.com/dvdfaq.html#3.4|title=DVD FAQ|at=[3.4] What are the video details?|author=Jim Taylor|work=dvddemystified.com}}</ref> They are output by the player to the [[composite video]] (or an available [[RF connector]]) for a connected TV's built-in decoder or a set-top decoder as usual. They can not be output on [[S-Video]] or [[component video]] outputs due to the lack of a [[colorburst]] 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. [[Windows Media Player]] (before [[Windows 7]]) in Vista supported only closed caption channels 1 and 2 (not 3 or 4). [[Apple Computer|Apple's]] [[DVD Player (Mac OS)|DVD Player]] 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 [[EIA-608]] 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).<ref>{{cite web|url=https://www.dvddemystified.com/dvdfaq.html#1.45|title=DVD FAQ|at=[1.45] What's the difference between Closed Captions and subtitles?|author=Jim Taylor|work=dvddemystified.com}}</ref> Many popular Hollywood DVD-Videos can carry both subtitles and closed captions (e.g. ''[[Stepmom (1998 film)|Stepmom]]'' 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/{{abbr|HOH|hard-of-hearing}} subtitle files on DVDs are reworkings of original teletext subtitle files.)

[[Blu-ray]] media typically cannot carry any [[Vertical blanking interval|VBI]] data such as Line 21 closed captioning due to the design of [[DVI]]-based [[High-Definition Multimedia Interface]] (HDMI) specifications that was only extended for synchronized digital audio replacing older analog standards, such as [[VGA]], S-Video, component video, and [[SCART]]. However, a few early titles from 20th Century Fox Home Entertainment carried Line 21 closed captions that are output when using the analog outputs (typically composite video) of a few Blu-ray players. 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".