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Captioning remains source of confusion in mixed NTSC, SD, HD world

What started out last week as a telephone briefing on new products closed-captioning system maker EEG planned to introduce at NAB2008 turned into a substantial conversation about the realities broadcasters face when it comes to fulfilling their FCC mandate to provide viewers with closed-captioning in a mixed-format world — one where NTSC, SD DTV and HDTV simultaneously exist.

Based on eight years of experience in the field supporting the DTV captioning requirements of broadcasters, EEG President Phil McLaughlin has some definitive views on what confuses broadcasters about 608- and 708-standard captioning and what they must do to avoid emitting an illegal DTV signal.

HD Technology Update: With the transition from NTSC to digital SD and HD, what are some of the issues broadcasters face when it comes to captioning, especially in terms of complying with the law?

Phil McLaughlin: First, what a lot of people all over the broadcast industry don’t understand is that the current FCC requirement is that both 608 and 708 captioning must be present on video regardless of whether it is SD or HD.

What complicates the matter is that the 608 data that is there is actually there only for downconversion to NTSC — for example, for use by coupon converter boxes. If you look at the FCC rules on decoders — whether they are TV receivers or set-top boxes, cable or satellite — the devices are not actually permitted to have just 608 decoders. They must have 708 decoders. So, the 708 decoder is the real deal.

There is no FCC requirement that a receiver or set-top box has to have the 608 decoder, but it does require it to have the 708 decoder.

So, what we are seeing now is rather than designing two decoders into every box, the newer generation of boxes really only has the 708 decoder. The transition ones had both. It’s kind of like the way serial ports are disappearing from computers. People don’t need them anymore, so they are just disappearing.

The 608 decoders are going that way, so the only place you are going to see 608 used, which is the only reason that it’s carried, is namely to provide a downconversion spigot off the DTV boxes. This is a poorly understood thing. For that reason, the requirement is that broadcasters have to provide native 708 service — real 708.

HD Technology Update: Has this been a source of confusion?

Phil McLaughlin: Many broadcasters are confused. They will decode the 608 and say, “There’s captioning on my DTV, and I’m done.” But you have to make sure the captioning that you have is actually 708. It can be translated from 608; that’s fine as long as it is done properly, but it has to be there.

A second thing to note about this 608-to-708 translation is that I prefer to use the word “translation” rather than “upconversion.” The reason I like to use translation is because 608-to-708 translation is inexact just as language translation is inexact.

If you get translation that is done by two or three equipment vendors, you will see two or three different translations. The formatting of the data may not be the same. The sorting of the rows of text into individual windows may not be the same. Some of them might scale if the user decides to put it into a larger font, some might scale perfectly and others might fall apart when they are scaled because the rows occlude each other.

HD Technology Update: How should broadcasters approach this inexact translation?

Phil McLaughlin: Basically, broadcasters really have to be watching what type of translation they are using, which raises the issue that people have to realize that in their plant if they’re bringing native material in, they might find a lot of different translations from 608 decoders to 708, which were not done by the original captioner. They were done by a piece of broadcast equipment that the broadcaster bought.

For example, when somebody buys an SD-to-HD upconverter, very often these devices are doing 608-to-708 caption service translation, but they’re buying that translation equipment from companies whose main business definitely isn’t captioning.

I’m not meaning to assault those guys, but that’s the last thing that they care about. They worry about their video; they worry about keeping their audio in tact. So, they say, “Well how hard can that be?” Often, they put what we call 608 in a 708 wrapper.

What that means is they have a 708 vertical ancillary service that’s on the HD video, but they do not actually have a 708 service. They only actually have 608 downconversion compatibility bytes being carried along, but they don’t have a real 708 service.

HD Technology Update: What are the ramifications of that?

Phil McLaughlin: If they put that signal to air and their ATSC encoder puts that out, that is not a legal signal. They’ll have a lot of confusion from the field. They can have deaf and hard-of-hearing viewers calling up saying there is no captioning. Yet, the broadcaster who is looking at it with a waveform monitor that can decode 608 data bytes thinks the caption is fine.

This creates a lot of confusion. People should understand what the cause of that is. This is very, very common. It’s all preventable, but it certainly can happen.

HD Technology Update: What other issues are raised by 708 captioning?

Phil McLaughlin: In terms of consumer electronic equipment, there’s CEA708, which is the standard for captioning. Then there is the FCC requirement for a decoder. Unfortunately, the FCC requirement of the decoder is actually more restrictive than the actual 708 standard. So, you can have something that is legal 708, but it will not play on an FCC-minimum requirement decoder.

Once again, this points out how important it is to know who you are buying from when purchasing 608-to-708 translation.

Is it from someone who has done the homework, been out in the field and will play on all the sets, or is it someone who’s trying it for he first time, and they want to test it out on you? If it’s the latter, you probably will want to run for the hills.

HD Technology Update: OK, given that the majority of programming broadcast doesn’t originate in-house, what advice can you give to prevent these issues?

Phil McLaughlin: One way to prevent a lot of the problems is to actually monitor the 708. You want a product that will show you the real deal; one that shows you the 708 the way the consumer will see it. That’s a great thing to have because it clears up a lot of ambiguity about what’s good and what’s not. I think it would be a good idea if people started moving to a little bit better monitoring on that.

HD Technology Update: Is there anything else you would like to add?

Phil McLaughlin: One other thing to note is there are many early ATSC encoders — particularly in the SD DTV market — which would take the 608 data and put it in a 708 wrapper inside the encoder. A large amount of the early equipment out there is doing this. People put their SD in it and assume the captioning is fine going out, but it’s actually only putting in the 608 data. In order for you to get the 708 data, you have to use an external translation box that translates the 608 to 708 and feeds it to the MPEG encoder with a serial port.

There are still an awful lot of broadcasters out there that are not doing so with that equipment. So, in effect, they are emitting an illegal signal.

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