New HDMI-capable CC Decoder

CCman

New Member
Anij: Good points. Keep in mind, I'm not generating captions, just displaying them. Since things like underlining, flashing and italics and colors are in the captioning standard, I'm compelled to consider them in my design. It would be good to hear how prevalent these features are used in general. I have seen italics in captions, so I think those are essential. I can't remember ever seeling underlining nor blinking text.

Thank you for the pointer to the font information. I will definitely consider user-scalable font sizes, although that poses some issues when you want to make the font larger - that is, what do you do with any text that overflows the screen?
 

FrugalFreak

New Member
DVD Models with 708 decoders

I am hard-of-hearing and I have been searching for the 4 player/recorders that are supposed to decode the captions and send over HDMI. I have found the Panasonic DMR-EZ28K, DMR-EZ485V but can't find the other 2 models. There are supposedly 4 models that work in displaying captions on HDTV from box source. Would any of you know the other two models? or any new players? I know I can view them over analog or component, but that defeats the HD purpose.
Only confirmed models please.

Thanks
 

CCman

New Member
john57: I have heard positive reports about Panasonic DVD recorders as well, being one of the few brands that will correctly capture and record the CC data on your DVD. But I'm talking in the analog video world, or perhaps using now-obsolete analog OTA broadcasts. I don't know if newer versions of these recorders with a digital ATSC tuner will capture and record the CC data stream on your DVD? If so, that would be very interesting.

However, it seems impossible that ANY device can display "CC over the HDMI" signal, simply because there is no closed caption data on the HDMI signal. Could you elaborate a little on this?

The box I designed accepts HDMI inputs AND the standard analog video as inputs, it then takes the CC data from the analog and overlays it as text on the HDMI signal passing through. While this might sound peculiar at first, many HDMI program sources simultaneously have standard analog video output as well (which is synchronized with the HDMI output, and contains the CC signal).
 

peternagy

Member
I have a home-built PC with Windows 7 and Media Center Edition. The PC also has two HDTV tuners. Media Center Edition records, preserves and displays CC over HDMI. The only drawback is that it only works with OTA antenna. It won't work with digital cable or satellite dish. I don't care because I don't want to pay for it.

The PC also has a Blu-ray drive. I use Cyberlink PowerDVD software to play Blu-ray/DVD movies. Cyberlink also display CC over HDMI. Media Center Edition can also play DVD movies and display CC over HDMI as well but I like Cyberlink software better.

Peter
 

CCman

New Member
Peter:

I have heard similar reports as yours. But just to clarify, technically speaking, none of the situations you have described are actually carrying "closed captions" over HDMI. Rather, your software/hardware has decoded the closed caption signal from the source program and displayed them on the HDMI video as "open captions". For some users, this distinction isn't important, but alas it is for me.

You source material variously has, or at least can have, embedded closed captions. Digital OTA broadcasts almost always have CC, many DVD's have CC, and if they don't, they at least have subtitles. A very few Bluray discs have CC, but again, they all have subtitles.

It's good to know your report that Media Center captures and records the CC signal. You mention the HDTV tuners, do you happen also have just a simple, analog video input as well?
 

peternagy

Member
Hi CCman,

Yes, I was already aware that CC is not part of HDMI signal but overlays onto video signal and transmits via HDMI.

That's how Panasonic or any other external sources do. All external sources that's CC capable super-impose CC onto video signal (or any other signal) and transmit thru HDMI cable as if CC behaves as sub-titles.

CC from digital OTA will only work with TVs with built-in digital CC decoders. As you already know that TV's with built-in DIGITAL (not analog) CC decoders will NOT decode CC from any external sources with HDMI. In order to see CC from external sources (DVD/Blu-ray players, cable box, satellite box, etc) using HDMI cable, you have to enable CC from external sources via on-screen menu. I am disappointed in the engineers or committees for leaving out CC from HDMI protocol standards. This is a very big mistake by HDMI committee. Not only it's a big mistake, it's very confusing to people migrating from analog to digital CC. It took me a long time to figure this one out.



For my HTPC, I have several different brands of HDTV tuners. Currently I am using HD Homerun Dual ( HDHomeRun (US/CA) « Welcome to SiliconDust ) which has two HDTV digital tuners built-in and no analog. As you already know that analog TV OTA is dead so there is no need for analog input tuner anymore.

My other brands HDTV tuners are Fusion ( DVICO FusionHDTV Tuner PCI, USB: Home ) and VBox DTA-150 ( ATSC Receiver, ATSC Terrestrial HDTV receivers, terrestrial broadband data, IP over ATSC ). The Fusion I have is no longer available. They both have analog and digital inputs. You can use analog cable and connect to analog inputs of the tuners. Analog cables are also dying. I no longer use these tuners but I am keeping them as backups in case HD Homerun fails.

Peter
 

CCman

New Member
Peter, thanks for the tuner information. I do wonder if the Media Center would decode and record CC signal from analog inputs. I'll have to research that some, it might be quite useful to me in my lab and for factory testing.

BTW, my interest in Panasonic DVD recorders is that they are one of the few manufacturers of DVD recorders whose products consistently will decode and record the CC signal from incoming (analog) video, and of course, generate the line 21 CC signal on (analog video) playback. For my engineering use, this is quite a useful feature. My only other way of generating a line 21 signal is a huge, bulky piece of equipment dating from 1994!
 

peternagy

Member
Before analog OTA went dead, analog TV recording included CC in Media Center Edition. But I am not sure if it was Microsoft proprietary CC or old fashion line 21 CC.

I started with Windows 2005 MCE at least five years ago when digital HDTV was around the corner. I started with DVI cables between graphics card and Sony HDTV with DVI input and I remember seeing analog CC as well as digital CC through DVI cables. I have never connected my HTPC to HDTV with analog cables like component or composite so I can't answer whether it was line 21 CC or Microsoft proprietary CC. I am willing to bet it was Microsoft proprietary.

I have noticed current Panasonic DVD players will transmit CC over HDMI cables but none of their Blu-ray players will support CC over HDMI. Last I checked was about 6 months ago. That's somewhat understandable because newer Blu-ray movies don't include CC but include sub-titles. That's bad for deaf people who still owns old DVD movies with CC but no sub-titles. How will they play older DVD movies with CC but no sub-titles in today's Blu-ray players? Like I said, blame on HDMI committees.

Peter
 

CCman

New Member
My limited testing with BluRay players (I have a Sony and a Samsung model) is that they WILL transmit Line 21 CC out the analog port. I haven't investigated whether they will decode and transmit them as open captions on the HDMI port or not - probably not, as this is kind of an unusual function for a DVD player. In fact, I've never seen any DVD player that can decode the CC data and display it as text. However, they certainly can display the subtitles as open captions on the HDMI output.

Just to point out, some Bluray moves indeed DO have closed captioning. Just not many. I have several titles here in my lab which I use for testing. And I'm not sure how Bluray handles NTSC vs. PAL - in the DVD world, line 21 captioning simply could not be stored on a PAL-formatted DVD, not for any technical reason, but simply it was not a part of the standard - line 21 was only included in the NTSC version of the standard.

Never heard of a Microsoft proprietary version of line 21. I can't imagine why they would do that, but then again, they are Microsoft. Like the old joke, where does a 600 pound Gorilla sleep? Anywhere he wants!
 

peternagy

Member
I am a firmware/software engineer and I know how Microsoft do their business. They don't seem to be creative on their own and steal other people's ideas like their C-sharp is practically a copy of Java.

So, I won't be surprised Microsoft did their own way of transmitting CC to TV via HDMI, probably behaving like sub-titles (or open caption).

I remember one Blu-ray movie I rented had CC and Cyberlink PowerDVD was able to transmit CC to my TV via HDMI. I forgot the name of the movie probably because it was a bad movie. :D

Peter
 

CCman

New Member
I think we need a different terminology when talking about displaying any type of captions, closed, decoded, or subtitles on the HDMI interface. There simply IS NO method to transmit closed captions on HDMI, period. If you see captions, or any kind of text, it is being superimposed on the video signal. On further reflection, there's no way Microsoft could change that, at least to have it work with a standard HDMI television (*). If the software is putting text on the signal, and you see it on your HDMI TV set, it really isn't closed captioning, but rather part of the video. A simple test I ask myself is this: if I wanted to, could I turn OFF these letters at the TV set?

So your Microsoft Media Center, there really isn't anything proprietary - they're just decoding the CC signal, and overlaying the text onto the video before transmitting it on HDMI. For me, I would like to know if their analog video output, on a computer so-equipped, can transmit the Line 21 signals. Or is it always overlayed video? I have read that there are some such video cards available that support Line 21 encoding, but haven't tested any.

Back to the nomenclature, in my project I have to distinguish between closed captions, decoded and displayed open captions (essentially permanently overlaid onto the video signal), and subtitles. It's very good to know that the PowerDVD player lets you choose to display either the closed captions or the subtitle tracks. Especially since the CC text usually contains a lot of non-visual cues, unlike subtitles. I'll have to keep that PowerDVD player mind.

(*) technical aside - I believe there is now an optional auxilary ethernet interface over the HDMI link. So theoretically a company might be able to encapsulate the CC data into ethernet packets, and send them to the TV that way. However, that would require a special TV that knew how to decode these ethernet packets and display them. I really doubt Microsoft is doing that.
 

peternagy

Member
Using HDMI and Media Center Edition with CC turned on in MCE, CC is displayed on my HDTV with CC turned off in TV. I believe you are correct that Microsoft simply decodes CC, overlays onto the video and transmit onto HDMI. I believe that's how all other external sources work including Panasonic DVD players using HDMI.

I can't answer your question about analog out of my HTPC since the HTPC has no analog out (composite or component). It has VGA out but I don't think the TV's CC decoder will decode CC from VGA cable. I have not used analog video signal for eight years since I first bought my HDTV with DVI.

I am curious. Why are you interested in analog out? Analog video in consumer market is a dying breed. It may be around for another 5 years and by then HDTVs will be cheap again.

Peter
 

CCman

New Member
Peter: good point. way back in the beginning of this thread, I introduced that I am making an external, stand-alone HDMI closed caption decoder. Since of course CC signal is not on HDMI, I am taking advantage of the fact that almost all HDMI video sources these days also have a simultaneous analog, component video output which DOES carry closed captions. (In fact, I believe this is a legal requirement in some situations). So my closed caption decoder has two connectors for each input, one HDMI for the video, and one composite video connetor for the closed caption signal. There is just one output, that being the HDMI signal (which can have captions overlayed or not, depending on the user settings of the decoder box.

My interest in the analog output is simply from a testing point of view. Both design and development testing, and factory production testing.
 

peternagy

Member
I think I understand. Sounds like it's not designed for the consumer market.

I have been confused lately about CC and component cables. My first HDTV was a 60" Sony LCD rear projection TV with DVI input. I had a Samsung DVD player with DVI and component out. In order for my TV to decode CC from the DVD player using component, I had to set the DVD component out to interlaced (non-progressive) since progressive scan does not support line21 CC. Of course, my old Samsung DVD player would not transmit CC over DVI which is about the same as HDMI 1.0.

It appears that modern TVs including mine (currently own 65" Panasonic plasma) may no longer decode CC from component (interlaced or not). I don't know why TV manufacturers would do that. Many people from this forum have similar issues with CC and component cables using newer TVs.

Peter
 

CCman

New Member
No, my product is indeed a consumer product. I'll be introducing a model soon for the deaf and hard of hearing community which should fully support closed captions (the current product only supports a limited subset for Pop-On mode only).

If you wanted to test your 65 in Plasma for the CC decoding capability, you can always plug in a simple standard analog video signal (containing CC) into either the Y or the G input. If the set decodes and displays captions, you're good to go (the color of the video won't be right, but that won't matter for the test).

But you are indeed correct, the line 21 signal is only specified for the standard 480i mode of analog video. In my opinion, this wasn't due to any technical reason, it just was never defined.
 

peternagy

Member
So your plan is to connect from an external source like DVD player with both HDMI and component out going into your product. Then your product will decode CC from component and overlay CC onto HDMI and finally transmit both HD video signal and CC through HDMI to the TV. Pretty clever.

Peter
 

CCman

New Member
that is correct. other sources include various satellite receivers and cable receivers, as well as OTA receivers. It seems to be working pretty well in about 95% of the installations so far. The few glitches seems to be from (a) less-than-perfect HDMI interface issues (HDMI isn't quite a plug-and-play as we would like), and (b) some occassional CC problems from the various program providers, such as garbled data or poorly synchronized data. We hope down the line to get some of these mose onerous problems resolved with the providers.
 

CCman

New Member
Well, I just tested one particular Samsung Bluray player (bd-c6600) and it does NOT have any option to display the CC stream, although it does pass it along on the composite video output port. I have another Sony model, but I can't test it now.
 
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