Closed Captioning (CC) is a process of displaying text on a television, video screen, or other visual display to provide additional or interpretive information. Closed Captioning is not part of the Blu-ray standard and it's an optional feature for displaying subtitles.

In the early days of Blu-ray, 20th Century Fox was the only studio to add Closed Captioning to their BD titles from 2006 to 2008. As of 2008, no studio has implemented Closed Captioning into any new BD in favor of bitmap subtitles.

Closed Captioning used for BDs (and DVDs) uses the EIA-608 standard, also known as "Line 21 captions" and "CEA-608", it was once the standard for Closed Captioning for NTSC TV broadcasts in the United States, Canada and Mexico. It was developed by the Electronic Industries Alliance and required by law to be implemented in most television receivers made in the United States.

It is assumed that the Closed Captioning files are inside the M2TS file along with the video*. The most common files used for CC (EIA-608 compliant) are Raw Broadcast Format .bin and Scenarist Closed Caption Format .scc (Field 1) / .scc or .sc2 (Field 2).

Just like Text subtitles, Closed Captioning subtitles can be customized by the user, such as font size, text colors, and background colors**.

Closed Captioning is still used today in North America (using the new EIA-708 standard) for television broadcasting, but respectfully, it is something of a relic from the past. Today, BDs (and DVDs) do not use Close Captioning and instead use bitmap subtitles, because it's more time consuming to support both formats, and Closed Captioning is an North American standard and does not work for other English speaking countries (Britain, Ireland, Australia, New Zealand) because they mostly used the Teletext system. Blu-ray's bitmap and text subtitles can work world-wide without issues.

Footnotes

• *Looked inside all of the files and folders of the BDMV directory of Fox's CC-enabled BDs. None of them had any captioning files outside of the M2TS streams.
• **Tested on a Sony BDP-S6700, Sony BDP-S1700, and Sony PlayStation 4 with Independence Day, The Transporter, Fantastic Four: ROTSS, Live Free or Die Hard, and the League of Extraordinary Gentlemen. (Cannot provide screenshots at this time, as VLC player does not support CC for BDs)
  

External Links

• EIA-608 - Wikipedia Page
  
• Scenarist Closed Caption file - File Formats Archive Team
• Adding Captions to DVDs 
• Info of the SCC format
  

 

Author(s) : Æ Firestone