New HDMI-capable CC Decoder

CCman

New Member
Hello. I am new to the group. I am a design engineer, having worked on several video set-top boxes using Closed Captioning over the past 10 years. I have a new project this summer to make an HDMI set top box which will also display closed captioning - therefore one will be able to watch high definition video, but still be able to view CC. This is something that has been missing or difficult to implement since the introduction of the HDMI interface. This will be an external box, similar in concept to older analog CC decoders, going between your receiver/player and your digital TV. It will work with many common HD digital video sources, such as satellite receivers, cable receivers, and up-converting DVD players.

So I have a few questions for this community:

This product will only process and display line-21 (EIA-608) style captions. Is this a problem?

Are the new features of digital tv's EIA-708 captioning very popular and used often? If so, which features of EIA-708 are most important?

Even though this box will only support line 21 captions, some limited user-control might be possible (like font-size or offsetting the captions on the screen).

How important would a multiple-input "switching" arrangement be (e.g., multiple HDMI inputs and one HDMI output)?

I realize everyone will have different needs and opinions, but I still would like to hear comments and feedback.
 

A

New Member
I would say ANY captioning is popular among the deaf and HOH. So if settop box is our only access to CC, we would definitely use it even it annoys us because it is not always the right font for our tv. (some can get too huge depending on the tv program)
 

Silentwolfdog

New Member
What's different between EIA-708 and EIA-608?

I guess anything that makes it less complicated would be good.

As poster above stated, any captioning is good.
 

CCman

New Member
The traditional, line-21 style captions are formally documented and defined in the EIA-608 standard (although as I recall, it wasn't 100% complete - to truly define a CC decoder function I needed a couple of additional documents, the old Telecaption-II report and perhaps one of the FCC documents).

The newer style captioning used in HDTV broadcasting is defined in EIA-708. It is a more powerful method of captioning. The problem of international fonts was addressed, and proportional fonts are also allowed. The user has some control over the display of captioning. For example, font size can be adjusted and positioning can be overridden by the user. The mechanism for carrying these new captions also reserves bandwidth to simultaneously carry the older line-21 style captions as well.

As I understand the current legal situation in the USA (please correct me if I'm wrong...), broadcasters are required to transmit either just EIA-608 captions, or both 608 and 708 captions (in other words, I have heard that sending just EIA-708 is not allowed at present).

Thanks for the comments so far - keep them coming please.
 

PowerON

Active Member
I would say ANY captioning is popular among the deaf and HOH. So if settop box is our only access to CC, we would definitely use it even it annoys us because it is not always the right font for our tv. (some can get too huge depending on the tv program)

seriously... we need to have three-size and custom font to allow people choice their perfer since all HDTV come with it, while the cable box have very limited which doesn't meet FCC's' digital CC.
 

Hask12

New Member
I'm just a hard of hearing person who depends on closed caption to watch TV or DVD's. Your explanations regarding what you are trying to do needs to be less technical and easier to comprehend so we can all understand exactly what you are trying to do or explain. You can't expect a lot of feedback from the average person if they are unsure what you trying to do and how you are trying to do it. For instance I have cable TV and get CC on a large number of channels, but not all. Will this system supply real time CC for all channels. Will it work on DVD's that currently don't supply closed captioning? Will it work on a computer?
 

CCman

New Member
Hask12 - sorry if I was too technical. To answer your question, this new box will only display existing captioned programs. The problem this addresses is cable and satellite boxes which either (a) don't display captioning, or (b) make it very difficult to display and control captioning. Regarding DVD's, that's a tough question - many DVD's, but not all, have captioning. To further confuse things, many DVD players, but not all, pass along the CC signal on the output connector.
 

ShariB

New Member
Hello. I am new to the group. I am a design engineer, having worked on several video set-top boxes using Closed Captioning over the past 10 years. I have a new project this summer to make an HDMI set top box which will also display closed captioning - therefore one will be able to watch high definition video, but still be able to view CC. This is something that has been missing or difficult to implement since the introduction of the HDMI interface. This will be an external box, similar in concept to older analog CC decoders, going between your receiver/player and your digital TV. It will work with many common HD digital video sources, such as satellite receivers, cable receivers, and up-converting DVD players.

So I have a few questions for this community:

This product will only process and display line-21 (EIA-608) style captions. Is this a problem?

Are the new features of digital tv's EIA-708 captioning very popular and used often? If so, which features of EIA-708 are most important?

Even though this box will only support line 21 captions, some limited user-control might be possible (like font-size or offsetting the captions on the screen).

How important would a multiple-input "switching" arrangement be (e.g., multiple HDMI inputs and one HDMI output)?

I realize everyone will have different needs and opinions, but I still would like to hear comments and feedback.

I have a couple suggestions for you:

1) Ask for volunteers to beta test your boxes for free before you market them and I'm sure you'll do this with different satellite and cable companies because they all have their own way of broadcasting.
2) It's very important that your box allows for multiple HDMI inputs. I want to watch shows from cable as well as from my DVD player. I can somehow do this now due to the CC converter through my cable box.

In addition, Netflix now allows movies to be shown on Wii, so no cable/satellite company is involved in this. As prices continue to skyrocket for television, more and more people will be dropping their cable/satellite service.

I'm barely hearing and am totally dependent on CC.
 

truffle

New Member
Controlling font size is necessary. Many newer HDTVs have such a tiny display that the captioning is almost worthless. Would such a box be appropriate to increase font size for an HDTV on cable or satellite, not just HDMI devices?
 

CCman

New Member
I'm not quite clear about your question - this box will go between your HDMI video source (cable receiver, satellite receiver, DVD player, etc) and your HDTV. Initially I envision the unit only doing HDMI video signals, although HD component video might be added in the future. Does this answer your question?

Your point about font size is noted.

Thanks for the comment.
 

GadgetQueen

New Member
Hello. I am new to the group. I am a design engineer, having worked on several video set-top boxes using Closed Captioning over the past 10 years. I have a new project this summer to make an HDMI set top box which will also display closed captioning - therefore one will be able to watch high definition video, but still be able to view CC. This is something that has been missing or difficult to implement since the introduction of the HDMI interface. This will be an external box, similar in concept to older analog CC decoders, going between your receiver/player and your digital TV. It will work with many common HD digital video sources, such as satellite receivers, cable receivers, and up-converting DVD players.

So I have a few questions for this community:

This product will only process and display line-21 (EIA-608) style captions. Is this a problem?

Are the new features of digital tv's EIA-708 captioning very popular and used often? If so, which features of EIA-708 are most important?

Even though this box will only support line 21 captions, some limited user-control might be possible (like font-size or offsetting the captions on the screen).

How important would a multiple-input "switching" arrangement be (e.g., multiple HDMI inputs and one HDMI output)?

I realize everyone will have different needs and opinions, but I still would like to hear comments and feedback.

Take note that some set top boxes do not transmit caption data through component video outputs and may fail to transmit caption data through the HDMI outputs as well, but this information will be difficult to get.

TV stations are supposed to broadcast both 608 and 708 caption data, though new, exempt channels will be required to broadcast only 608 caption data when available.

I'd say the most important features of EIA-708 are the color of the text (bright yellow instead of mustard, please), the color of the background, the sizing of the text, and the ability to use a better font when horrible-looking fonts have been selected which don't actually become large (even when set to large).

For your purposes, if you can try to select a very good, highly readable font (instead of an overly thin font with the letters much too far apart) and which actually changes in size without disappearing off the right side of the screen...that would be nice. (By the way, some news stations automatically indent the captions on the left side by a couple of spaces, which happens to force long sentences with large captions to have the last two letters disappear off the right side of the screen. For this reason, you may want to have the largest size be just a little less than 30/32 of the screen, but a small TV screen will need to have the largest size possible, so don't make the large size too small.)

You might also want to consider providing only a semi-solid background for the captions----take a look at the background behind the captions in Windows Media Player, which have very nice contrast.

Make sure you provide a caption preview that's accurate. Many previews aren't accurate at showing how the captions will actually look.

If possible, I'd suggest providing more than one default setting for optimal viewing, like large captions with yellow text on a semi-solid black background, but still allow people to change the features.

People who have both hearing and vision impairments would really appreciate being able to attach external equipment like a refreshable braille display to the decoder (find out what kind of output is needed), so you should probably contact the American Association of Deaf Blind to find out more about how to make the decoder compatible with external equipment used by that population.
 

A

New Member
Yes, think about low vision blind and colorblind deaf people. Some low vision blind say they can do well in yellow fonts but I'm not blind so I can't be absolutely sure.. (I hope they will chime in and tell you themselves to be accurate)

Me, I do fine with plain old captioning as long as the font is clear. Nothing fancy.

I don't like closed captioning filling up the whole tv this happened to me when I was watching news. they keep stacking up rows of captioning on top of each other - like 3 layers or so)
 

Mayguy

Member
Will such box will work with X-box 360? We have one, and there are some DVD video don't have subtitle, and I have to put it in the non-HD player to watch the movie in CC, where the Xbox don't show CC.
 

CCman

New Member
MayGuy - well, if the X-Box doesn't output CC, even though the disc has CC, then there is no way that the box I'm designing could work with the X-Box. That said, I haven't specifically tested an X-Box to know for sure.
 

CCman

New Member
Ok, as my design progresses, I have some more questions regarding text attributes. (Please remember I'm talking about the old style, Line 21 captions, and not the new HDTV captioning style).

The law governing the design of caption decoders specifies that text can be displayed "with any or all of four attributes: Color, italics, underline, and flash," and furthermore the display of color text is optional. While the verdict is still out, it appears that I might not be able to easily provide this complete functionality. That is, any random combination of all of these attributes.

That said, I know practically speaking color attributes are rarely generated in the programming source. I know that the move "Pete's Dragon" used color captions, but not many other movies or programs. If my information is incorrect, please tell me. (note that I'm talking about displaying color attributes embedded in the CC source data, and not the user's ability to change the overall text display color).

Regarding Italics, the law requires either an Italic font or a slanted, regular font. However, "the user may be given the option to select other methods of italic display as well." I'm not familiar with this - can anyone give me an example of optional display of italics that some decoders might offer? How about just displaying them in an optional, second color?

For underline and flash (at least once per second), there isn't any alternate display allowed by the law. I would be curious just how widespread the use of underlining and flashing text is in CC material? In my testing of movies and programs in the past, I can't recall seeing either, although I don't watch a lot of captioned material outside the lab. If I chose to vary from a standard, compliant decoder, and made up my own alternate display method (again, perhaps a different color) would this be distracting?

Thanks in advance for any comments.

p.s. let me point out that my product does not have to be compliant with the law on closed captioning decoders, but I want to make a best effort to be compliant if at all possible.
 

Anij

Well-Known Member
I think that for fonts it would be good to have the following:

Regular (for speech)
Italic (to indicate either a speaker,special effect/room sounds etc)
Colour (to change the colour for ALL CC text, to accommodate colourblind/low vision)

I don't think it's necessary to be able to have underline function or assign different colours for various speakers/sounds etc (so shifting from one colour to another through out a movie/programme etc) - it tends to distract more than anything and the only really "readable" colours are white, yellow and MAYBE the light blue colour...the rest just are annoying IMHO)


I do think that being able to adjust the size of the font would be very good if at all possible.

If the font is pre-determined, for what it's worth the CNIB (Canadian National Institute for the Blind) recommended to me when I was doing some research for a university paper on accessibility, that "Tahoma Font" is the easiest (or one of the top 2 easiest) "readily available font(s)" to read. CNIB also has a down-loadable font especially designed for low-vision accessibility which is VERY similar to Tahoma.)
 
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