Monday, June 21, 2010

HDTV and closed caption

I went to Billy's house again last night and tried to turn on closed captioning. For some reason it doesn't work on his Toshiba HD-TV. I thought it might be the cable box. So I tried to turn it on while playing a DVD (Live Free or Die Hard) [not Blu-Ray] and that didn't work either. Of course the subtitles worked on the DVD. [Hmm. Looking up Live Free or Die Hard on amazon. Doesn't say it supports closed captioning, so maybe it doesn't. Will have to try another DVD that does.]

So that made me wonder if there's a problem with HD-TV and closed captioning. And apparently there is.

Here's an article from 2007.

As high-definition TV gains momentum in the United States, broadcasters, set-top box manufacturers and cable and satellite companies are struggling to provide closed captioning.

While most older analog sets provide captions with the touch of a remote control button or via a simple on-screen menu, it's more complicated to get closed captioning on the newest digital TVs that get their signal through cable and satellite boxes rather than antennas. That's because the signal is processed by the box and the caption settings must be matched to the resolution of the TV display.

In addition, most high-definition cable and satellite set-top boxes control the caption settings through often obscure and confusing menus.

"I learned that ... digital captioning options must be controlled from the cable box via a hidden menu that comes with no instructions," wrote Pamela Holmes, a deaf cable customer in Madison, Wis.

In an e-mail, Holmes said it took nearly 12 hours with installers, phone support and other resources to get her closed captioning operating.

Further complicating things, people are now discovering that if an HDTV set is hooked to the cable box through a connection called HDMI, captions won't be displayed at all.



I bought this TV the other day and I'm waiting for comcast to come out and hook it up tomorrow. I was going through the manual and it says that closed caption is only available on the TV, AV, and S-Video mode. I'm hearing impaired so I use the CC all the time. Does this mean if I connect the cable box by HDMI or Component cables that the closed captions won't work? ANyone who could try this for me or knows a solution for this would be greatly appreciated!

I see what you saw in the manual so I tried in a HD station with my cable box over HDMI and I could not select caption from the menu. I think the reason for this is because the cable box has its own closed captioning. I went into the settings for the box and was able to use closed captioning that way.


From Wikipedia:

Many viewers find that when they switch to an HDTV they are unable to view closed caption (CC) information, even though the broadcaster is sending it and the TV is able to display it. Originally, CC information was included in the picture ("line 21"), but there is no equivalent capability in the HDTV 720p/1080i interconnects between the display and a "source". A "source", in this case, can be a DVD player or an HD tuner (a cable box is an HD tuner). When CC information is encoded in the MPEG-2 data stream, only the device that decodes the MPEG-2 data (a source) has access to the closed caption information; there is no standard for transmitting the CC information to an HD display separately. Thus, if there is CC information, the source device needs to overlay the CC information on the picture prior to transmitting to the display over the interconnect.

Many source devices do not have the ability to overlay CC information, or controlling the CC overlay is extremely complicated. For example, the Motorola DCT-5xxx and -6xxx cable set-top boxes have the ability to decode CC information located on the mpg stream and overlay it on the picture, but turning CC on and off requires turning off the unit and going into a special setup menu (it is not on the standard configuration menu and it cannot be controlled using the remote). Historically, DVD players and cable box tuners did not need to do this overlaying, they simply passed this information on to the TV, and they are not mandated to perform this overlaying.

[In other words, you got to turn it on from the cable box. Somehow.]


Here's how one user turned on closed captioning on his cable box.


Here's Oceanic's solution

There are no graphics, closed captions or program guides appearing on the TV screen.

1. The DCT cannot generate graphics on all video outputs at all times. If the DCT is set to 1080i, 720p, or 480p output formats, graphics are only available on the high definition video outputs (DVI and component video). If the DCT is set to 480i, graphics are available on all video outputs.
2. If the DCT is connected to a standard definition TV, verify the DCT is configured to use the 480i output mode.
3. Verify closed captions on the DCT have been enabled in the User Settings menu.

So what does DCT mean?

Digital Cable Terminal, the generic term for the set-top box required to receive digital cable.

*** verifies all of the above (or just read this first without reading everything above :)

Q. Does HDMI support Closed Captioning?
Close Captioning

The evolution from analog to digital TV has added some complexity to Close Captioning (CC). With one standard way of broadcasting/transmitting, decoding and displaying content NTSC or PAL, depending on region, analog TV made enabling CC fairly easy across CE devices since the TV was able to do all the CC decoding.

With the advent of digital TV and the introduction of digital HDTV services (cable, satellite, etc.) the responsibility of decoding CC has been taken away from the TVs and put into the various Set Top Boxes (STB) that are required for the majority of the digital HDTV services. Additionally, these STBs now have different ways of enabling CC making it complicated and creating confusion for consumers. All set-top boxes are required to support CC, however the implementation of CC can vary from one product to another. Enabling CC on a specific set-top box can be simple, or more difficult, depending on the implementation.

HDMI, LLC recommends contacting your TV service provider (cable, satellite, etc.) for the correct way to switch on its CC feature as a first step to resolve this issue. The second step is to contact the manufacturers directly for the correct way to enable the CC feature within your product.

How CC works in HDMI and other digital connections:
The TV remote's CC button does not enable/disable CC on HDMI sources. To enable CC, the user must enable it at the source either through a source remote control key (i.e. CC button) or by going through the setup menu of the source. The source will then combine the video content with the CC information and output that (video + CC) via HDMI to the TV.


Hmm. Never noticed if closed captioning worked on my digital channels (on my SD-TV). Let me see...

OK, it works on both 5 and 85. So evidently it's not a digital problem but a hi-def problem. Well I should say it's not the digital signal, but the digital TV.


Well, I guess I'll have to wait to get my hi-def TV first to know for sure, I guess.


On a related note, does Blu-Ray support closed-captioning?

Since Blu-ray is now accepted (for the most part) as the new HD disc format standard, many questions have come up about closed-captioning and subtitling for Blu-ray Disc (also referred to as BD).

First off, to get the record straight, Blu-ray does not support closed captioning. This is for a very logical reason: Subtitles can be turned on and off through the disc’s menu (just like an SD DVD), therefore there is no need to add the closed captioning option. Consequently, BD does not carry Line 21 due to its High-Definition Multimedia Interface specs (HDMI). These specs were designed to displace the older digital and analog standards.

[so does that mean every Blu-Ray disc has subtitles?]

[yes, according to reply #8]

From Wikipedia:

HD DVD and Blu-ray disc media cannot carry Line 21 closed captioning due to the design of High-Definition Multimedia Interface (HDMI) specifications that were designed to replace older analog and digital standards, such as VGA, S-Video, and DVI.


To make it even clearer, apparently the HDMI cable does not support closed captions. And closed captions appear on an interlaced signal, so it's not supported by progressive mode either.

OK, that sucks. That means I would have to hook up my DVD/Blu-Ray player via composite cable to view closed captions on DVDs.

But apparently some DVRs support closed captioning with HDMI (see replies #5,6,8). I wonder if my Toshiba has it? [9/1/10 - don't see that option]


[9/1/10] Finally got my HD DVR and found (looked it up) that I can turn on closed caption as one of the options when I press the setting button on the remote. Cool.

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