SSW Blog

Distortion of HDMI’s Role with CC

Posted on | February 24, 2010 | 3 Comments

There is confusion when some people found no closed captioning (CC) appearing on their HDTV and agreed that HDMI was a factor to cause problematic.  Wait a minute; it is not HDMI. Perhaps cable or satellite provider should provide set top boxes, receiver boxes or tuners. Or, perhaps you did not set up right with hooking up the cables.  Some instruction manuals are not clear about CC and, however, we step back and re-read it about how to set up the cables properly with the HDTV system.

Unfortunately, the Television Decoder Circuitry Act (TDCA) is restricted to televisions with greater than or equal to 13 inches requiring built in CC decoders.  Why not the TDCA extends to some other equipment like XBox, Play station, DVD or Blu-ray players? This amendment had been proposed by the Coalition of Organizations for Accessible Technology (COAT).  Funny, this current TDCA had not mentioned any about analog and digital technology.

Reading Rate of CC – 125 words per minute
Spoken Dialogue – 200 words per minute
Limit of Analog CC Input – 250 words per minute

What’s more, we end up to be unfortunate being frustrated with Digital TV (DTV) and now HDTV.  In near future we will face another possible frustration with 3D TV.  Why must we be the ones to figure out how CC should work as though we are not the experts in the area of electronics?  Silly of FCC, manufacturers, TV or video producers, they had believed by getting away with a clever shortcut by converting analog CC to digital CC via conversion box as so called well-known “converter box”.  I bet that they were relieved after the converter box works as if it is a dressing or bandage.

First, as you had recalled that we had switched our analog signals to digital signals during the era of the Digital TV Transition, some broadcasters like local TV stations, or cable providers would assume after no more use of analog signals to “turn off” analog broadcasts. They do not realize that they have to continue the analog signals in order to enable analog TV to understand analog CC, not digital CC.  So it would be able to carry through analog signal to enable digital CC.  Does this explanation look confusing to you?  Perhaps you may say, “I know that, but what about HDMI?”

Please hold your hands; we need to be aware about how both analog CC and digital CC work together. Guess what, there is no such way to “down convert” from analog to digital CC as if switching analog CC to digital CC just like TV but it does not work that way.  There is no such hardware to encode digital CC straightforward.  That is the bottom line that FCC has neglected to include this essential part into the CC rule.

Now back to HDMI’s role, HDMI refers to High-Definition Multimedia Interface. There are six or so different upgrades from HDMI version 1.0 to newest 1.4 since 2002 a first version of HDMI was 1.0 but it was limited to the DVD audio. I don’t want to jump into the discussion about HDMI versions but I trust you will find several useful links below.

Sadly, HDMI doesn’t have mandatory standards for CC as well as not MPEG-2. I bet you would say, “What the heck is about MPEG-2?”  Did you know that CEA-708 captions are carried as data within the MPEG-2 bit stream?

In case after hooking up with HDMI cable there are several CC issues:

  • No captions on the screen
  • CC looks scrapped on HD programming
  • Some CC are not working on some TV brands
  • TVs are made prior to 2002
  • Misleading instruction manuals
  • HDMI versions
  • HDCP – copyright protection – causes “errors”, black screen or encrypted. Some products are non-HDCP.

Misconceptions of HDMI and CC

Some people ask whether HDMI works with CC. Or, whether HDMI does not carry through CC.  In reality the HDMI standards do not require CC and so there are two different stories between closed captioning and HDMI as well as separate issues.

Surprising some several HDMI versions support CC.  For this blog I would clarify misconceptions of HDMI cables that support closed captioning.  Simply put, I would classify the cable classes in analogy; HDMI is first class for video and audio quality although it is called as king of high quality connection. Sometimes HDMI works fine or not.  You may replace another video cable that may work better than HDMI. (See below video cables) So you don’t have to require HDMI cable as you would be able to use different video cables.

I had used component video cables to hook up with DVD recorder since I prefer analog CC as long as any DVD diskettes that indicate available symbol CC.  For Blu-ray player, I hooked up with HDMI because it does not make any difference because almost all Blu-ray diskettes come with infamous “SDH”. It works fine but the picture is very beautifully high quality.  XBox is hooked up with HDMI cable as though I had used component cable before I had afforded HDMI cables. In either of both cables XBox works fine but I had not noticed any CC  so far.  I had used HD DVD diskettes and SDH works fine anyway on XBox. I suspect there is lack of CC available through On Demand Videos like Netflix, Amazon or Microsoft.

Video Cables:

Composite Video – Capable of 480i, maximum resolution of Standard Definition TV (SDTV).  (480i lines of resolution in an interlaced format).

S-Video – Capable of 480p, maximum resolution of Enhanced Definition TV (EDTV) and 480p (SDTV). (480p lines of resolution in a progressive format).

Component Video – Capable of High Definition TV (HDTV) at 720p, 1080p and 1080i, EDTV at 480p and SDTV at 480i.

HDMI and DVI – Capable of High Definition TV (HDTV) at 720p, 1080p and 1080i, EDTV at 480p and SDTV at 480i. Resolution is sharper than component video.

I know it is not easy and especially we are not qualified in electronics. That is the cable or satellite provider’s profession and however, I could not believe why they are not familiar with CC system. We had unwillingly taken over their jobs and used our judgment call based on trial and error by instruction manuals in order to assure that CC works. It is no laughing matter – because we need CC badly for access to the TV and otherwise TV, DVD or XBox may be worthless.  Disappointed, we  are being “forced” to do our dirty hands by just resolving CC. It is thanks to the providers and TV salesmen as if they rather “pass the buck” by ignorantly admitting about no idea of how CC works.

Should you have any similar experience regarding CC and HDMI issues, please feel free to share your comments.



  • grwebguy

    “infamous” SDH. Are you for/against?

  • cmssw

    I am “for” . SDH needs more work!

  • John @ video cables

    This article is so great. I totally agree that SDH really needs to work for more to obtain great service to their users.