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.
HDMI and Close Captioning
Closed Captioning (CC) works differently with digital connections (HDMI, DVI, etc.)
How old analog CC worked:
Source always sent CC information to the TV and the TV controlled whether the CC was displayed or not via the TV's remote (CC button). The CC button on the TV only controls CC for analog connections (S-Video, Composite, Component) or Over The Air tuners (ATSC digital or NTSC analog)
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. (That's called overlay CC)
The CC rendering is done at the source and not at the TV as it was with analog connections. For example, with a typical cable box the CC is enable by going to the cable box setup menu and not the TV remote's CC button. The TV remote's CC only controls the analog CC and does not control the CC for each of the HDMI source devices. CC must be enabled from each of the individual HDMI sources.
Exact steps to enable CC varies between manufacturers so please contact the source manufacturer for instructions.
