One of those big difference between UK subtitling and US captioning is the use of colo(u)r or the absence of it (https://www.bbc.co.uk/accessibility/forproducts/guides/subti...), which I believe boils down to technological differences between television systems in the '80s. While the UK-developed teletext system is also available in NTSC (in fact CBC have deployed it), the US opted out to develope a separate captioning system that only supports basic text and positoning.
I'M NOT SURE IF THIS IS BECAUSE
OF GOOD OLD PROTECTIONISM OR
CONVERTING STATIONS TO HAVE A
TELETEXT COMPUTER ON EVERY
STATION IS IMPRACTICAL IN THE US
WHERE, AT THE TIME AT LEAST,
THERE ARE A DIVERSE NUMBER OF
BROADCASTERS WHICH MIGHT NOT
AFFORD THE EQUIPMENT NEEDED
SINCE TELETEXT IS AN "ACTIVE"
SYSTEM WHEREAS THE PBS-DEVE-
LOPED SYSTEM CAN BE USED ON
EXISTING, CAPTION-UNAWARE
SYSTEMS
... while the UK only had two broadcasters at the time, which are the BBC and the IBA (Independent Broadcasting Authority*), it is easier to develop and actually broadcast teletext.
* Despite their name suggesting that it only monitors broadcasts, they are actually the broadcaster which has the authority to install teletext equipment. The then-ITV companies are only program suppliers to the IBA, not broadcasters in their own right.
The Closed Captioning System for the Deaf - which became known as "608" - was always capable of displaying captions in color.* However, this faculty was largely underutilized, due to a variety of historical / technical reasons.**
* Indeed, the first test broadcasts from 1979 included color.
** This is due to the design of the original 1980 "decoder," which only 'worked well' for color when installed inside an NTSC television. For the external adapters, grayscale instead of color was displayed. The only way to view color captions in color back in 1980/1981 was with a TeleCaption TV - and there was only one model ever made.
The older “608”[1] system in North America was much simpler but the current “708”[2] standard does support specifying colours and fonts, but in my experience in the industry nobody uses those functions at all and just uses the 708 function to embed the older 608 payload data within the newer 708 data structure.
In UK/Europe the older/simpler format would be OP-42/OP-47 Teletext[3] which can be used for captions instead of the full-screen data pages, or DVB Subtitles[4], which get into more uses around “subtitles” in terms of language translation, rather than only the “closed caption” use case where it matches the content language. DVB subtitles can be sent as pre-rendered bitmaps or as data for client-side rendering.
There are very strong lobbying groups that push for accessibility in terms of captions (as well as the “DV” described video audio track) but my impression is that their focus is on the quantity of content that’s covered, and the quality (spelling, time-alignment), and I guess they don’t care as much about text styling.
The requirements are quite high in Canada[1] and have been expanding in the US as well[2].
The company I work for makes products for broadcast customers, around asset management, linear playout automation, and the playout servers that insert the captions (from files or live data sources) so working out how that all happens is part of every big project.
In my experience with a few big broadcasters like Paramount (previously Viacom) and Discovery, for broadcast in Europe/UK the signal they generate often has a mix of Teletext and/or DVB inserted based on the channel since those signals are distributed to a LOT of partners like local satellite and cable companies who can decide which parts of the signal to map into their system.
In that context, “teletext” just works the same as the North American 608 captions and has nothing to do with the older full-screen data stuff. There are no restrictions around authority for “teletext equipment” - for those channels they actually use systems fully based in AWS with the playout engine running on an EC2 instance so all software-only to generate the single MPEG transport stream with video/graphics + audio + captions + subtitles.
It’s also common to send a DVB subtitle multiplex that has a number of languages (up to 20+) embedded in the same signal.
I was under the impression the "teletext" style ones still used teletext encoding, not EIA-608? It's basically just a data steam containing a single page of teletext rather than a whole magazine? AFAIK Sky Digital uses this approach (at least for SD), with a more modern looking decoder, and it certainly has colour support at least[1].
[1] Although DVB can contain a full teletext stream that can be reinserted into the SD analogue VBI by the receiver. Sky boxes supported that so on some channels you could just go to ye olde page 888, although I haven't a clue if any channels still do that (I don't have an old SD Sky setup around to look).
That's correct - 608/708 is North America only, and UK/Europe could use OP42/47 teletext for simple captions (not whole magazine), and/or DVB (mostly language translation).
To be fair, I'm talking about the old PAL-based teletext and not about DVB teletext. Also, computers are now everywhere so the 888 page can be inserted with minimal effort unlike back then that it requires coordination with different teams.
I was talking about the older PAL-based teletext as well - but you're right, I understand it was different in terms of equipment originally with the full-screen data feeds.
Separate from DVB, the old PAL OP42/47 teletext payload gets inserted into the MPEG-TS using SMPTE 2038[1] then when decoded, it would go into regular ancillary data of the uncompressed stream per ITU-R BT.1120-7[2].
For (foreign-language) subtitles that seems distracting and unnecessary, since even if you don't see the character speaking, you can recognize their voice.
But for closed-captioning (for the hard of hearing), it seems like it could add clarity. Yet in the past I've watched movies with CC without sound (like on a long-distance bus) and don't remember ever having a problem understanding who a line belonged to.
Does anybody have actual experience with color-coded captions and whether they're more of a help or more of a distraction?
Why would it be distracting to know who’s line it is without color coding? Why would color be the thing that distracts you; wouldn’t the actual captions be far more distracting?
As to why: it’s another datapoint to use to reconstruct what fully able people can do quickly. Sometimes captions aren’t well timed. Sometimes a lot of things happen very quickly and it’s hard to keep track. What if the camera isn’t on anyone’s face? You can probably figure it out by context, but why expend the mental energy when it can just be colored?
Just because you never had this issue (and I’m sure you did, it’s not like we remember the most mundane of details like this years later) doesn’t mean it’s not an issue.
You have a single set of guidelines (BBC doesn’t have two sets, nor does any other provider I know of) and a single set of subtitles as a result.
This is accessibility like anything else. High contrast can be used by many people on the ability spectrum for multiple various reasons. Subtitles are the same. Some use them because they’re deaf, some use them because they’re not confident enough in a language to use only one sensory input, some just like subtitles.
But since your claim is they’re separate, please show me exactly how they are separate. Show me the two separate style guides, show me providers differentiating between them and providing both captions and subtitles. Show me even the smallest sliver that backs up your claim. And, more importantly, show me the exact reasoning why color would work in one but not the other.
Captions like “[ upbeat music ]” or “[ computer beeps ]” signal to deaf listeners information about the program that they cannot sense. There is no need for those when adding subtitles to a foreign-language program made for a hearing audience.
Similarly, subtitles are necessary for on-screen foreign language text (e.g., signs or documents), but not when the text is in the language that a deaf viewer understands. For example, you wouldn’t have an English subtitle for an on-screen sign in English, but you would for an on-screen sign in Chinese.
The BBC produces content exclusively (or nearly exclusively) in English, so these guidelines are surely directed towards captioning of English-language content for hearing-impaired, English-reading audiences.
* Despite their name suggesting that it only monitors broadcasts, they are actually the broadcaster which has the authority to install teletext equipment. The then-ITV companies are only program suppliers to the IBA, not broadcasters in their own right.