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MAG Guide Vol. 6

Information on how to reformat closed captions
Closed captions created for a specific program can be used again -- or "reformatted" -- for subsequent distribution. Whether programs are changed slightly or edited heavily, the original captions can be reformatted to fit the new version of the program for a fraction of the cost of the original captioning job.

Television viewers who are deaf or hard of hearing often ask the Media Access Group at WGBH why a program airs originally with perfect captions, only to reappear on other channels or in home video with missing or garbled captions. We also hear from distributors who, unaware that a captioned master already exists, spend significant amounts to needlessly recaption a program. Often, the captions originally created for a program get lost or scrambled along the distribution chain.

Most programs created these days have an extended life in multiple markets. It is more important than ever for those acquiring programming to request and if necessary reformat the captions, which are as vital to the nation's 24 million viewers who are deaf or hard of hearing as audio is to the general hearing audience.

We hope this MAG Guide helps producers and distributors take advantage of and preserve captions created for the original airing of a program as they redistribute in other venues. The simple step of reformatting can add value to a program and save hundreds of dollars in captioning costs per episode.

Editing video vs. editing captions
Captions are anchored to a program's SMPTE time code, and any edits or changes in the program will require separate edits and changes to the caption data.

When a program is captioned, the transmission of each caption occurs during a one- or two-second period prior to its appearance. In other words, the packet of instructions sent to the caption decoder -- where the caption will be placed, how long it will stay there and what it says -- is sent to the decoder before it displays anything. Editing a captioned master can interrupt or destroy parts of these packets, causing garbled and/or missing captions.

The same thing can happen when a program is time-compressed. The compression equipment removes occasional frames of the video, along with any caption data they may contain, resulting in garbled and/or missing captions.

Obtaining captioned masters
Most often the only captioned version of a program is the "air master." The archive or library master is rarely captioned. When acquiring a program that has aired or will air before you receive it, we suggest you check with the original producer, rights owner or distributor to ensure you'll have access to the captioned master.

If you receive caption files on disk from a broadcaster or distributor, make certain you understand what you're getting. Some caption file formats are readable and can be edited with captioning software. However, many times the broadcaster or distributor receives an "encodable" file from the caption provider. This type of file has strings of computer codes (binary data) mixed in with the captions which work with specific software during the encoding process. Captions are thus time code-stamped for the original version of the program and will not work correctly with versions, which have been edited or time-compressed.

Most programs that appear on the broadcast networks, and many that debut on cable networks, are captioned. If you are uncertain as to whether a program has been captioned, please contact us. We will do our best to help you find the captions created for your program. The original caption provider should have archived files for your program and can edit them to match your version. You can also ask for an ASCII file of the captions, which can be used by most caption providers to reformat the data.

Reformatting: A two-step process
* A videocassette of the new version is compared with the existing caption file. Adjustments are made in the captions to accommodate the addition or removal of commercial blacks, new material, edits or any other changes.

* The reformatted caption data are encoded on line 21 of the vertical blanking interval (VBI) of the new version. Many post and duplication facilities have the equipment necessary to encode captions. Check with us for a list of encoding facilities in your area.

Reformatting captions for DVD
Captions can easily be reformatted for use in most DVD authoring systems. We can create a line-21 caption file for inclusion onto the DVD. This will generate traditional line-21 captions as the DVD plays, which viewers decode with their normal caption decoders. We can also convert the caption file to English subtitles and create bit-maps and play lists for most DVD authoring. These subtitles become a choice on the DVD menu and are turned on or off through the DVD player. To further enhance your DVD, we can create additional streams of subtitles in other languages.

PAL closed captions
Different types of captioning are used for broadcast and home video in the PAL universe. Captions similar to our NTSC captions are used in PAL home video, while teletext is used for broadcast. We can reformat your NTSC captions for PAL home video, and we can direct you to the teletext vendor who supplies your foreign licenser for your teletext needs.

If a program originally aired in the UK, Australia or New Zealand, teletext captions may have been created. While it is technically possible to convert and reformat teletext captions into a usable form for NTSC countries, keep in mind that there are vast differences in style and conventions between captioning created in North America and that done elsewhere. While US and Canadian captions are for the most part verbatim, captions created in the UK are heavily edited and may not fully serve the American audience.

For additional information about reformatting or recycling closed captions, Contact us.

Caption Services Description Services NCAM