Closed Caption how do they do it?

Rednroll wrote on 1/13/2005, 6:08 AM

CC...I think that's what it's called? It's where you put your TV on Mute and somehow the TV has the ability to put subtitle text on the screen. I always thought this was extra data the cable company broadcasted with the video signal for the hearing impaired and I always felt sorry for the lady typing away frantically during a live news broadcast. Then I noticed it on a VHS rental and figured somehow that information must be embeded into the video signal on the tape? Either that or my Panasonic TV's voice to text conversion is amazing!!!!......but then I unplugged the audio inputs and it was still there!?...I said HOLLY SH*T!!!!! THIS PANASONIC TV CAN READ LIPS.....EVEN WHEN THE PERSONS FACE ISN'T ON SCREEN.

So my question is, how do you create and render a video with this CC text messages that follow the voices in the video? Can you do this type of thing in Vegas? Could I say Create a video in Vegas with CC, then play it back through the preview to external monitor and have the video signal routed to a VHS deck and record it, then my VHS would have CC information encoded on it? How about VCD? There's subtitle options on DVD's so I understand this, but VHS this is like smoke and mirrors stuff to me.

Comments

Jay Gladwell wrote on 1/13/2005, 6:21 AM

It requires special encoding that is capable of being read by CC decoders. Plenty to be found about it online.

Start here.

Jay

Spot|DSE wrote on 1/13/2005, 6:49 AM

Vegas can insert markers/metadata that can be read by a number of different applications. AFAIK, Vegas was the first NLE that could direct-embed metadata for Rule 508 compliance.

Former user wrote on 1/13/2005, 7:07 AM

CC is encoded on line 21 of the video picture. If you see a picture on overscan, you will notice the white marks at the top of the screen that flash off and on. These are basically digital type signals that spell out the words and commands. A CC decoder reads these flashes and translates them to text on the screen.

CC has been around for several years. It has only recently been required by the government that all TVs have the ability to decode it. Until now, you had to have a special external decoding box.

Live Captioning, like on news shows, is done the same technical process, but you have someone, similar to a court stenographer, typing on either a computer or a steno type machine while the people and reporters are talking. That is why there is a bit of delay. It is similar to a live translator.

There is also open captioning, which is where the text is part of the video. This used to be very common before the government requirements, especially on children's programming. The idea being that not everyone could afford a CC decoder, so in order to allow access for these people, open captioning was sometimes broadcast.

A DVD captioning is a digital process totally different than VHS or TV captioning. You need special authoring software, such as Scenarist, to include captioning on a DVD.

Dave T2

Rednroll wrote on 1/13/2005, 7:54 AM

Thanks for the explaination Dave T2, this helps a lot. I'm just a little confused by Spot's comments, when he says Vegas can do it with Meta Data "that can be read by a number of different applications."

Applications? What applications? I want it to put the white pulse information on line 21 like Dave outlined and have my TV be able to decode it. Does Vegas have this ability? Is that what it does when you say it embeds "metadata for Rule 508 compliance."? So basically if my TV's CC decoding feature is Rule 508 compliant, then it would display the text?

Former user wrote on 1/13/2005, 8:04 AM

I amy be wrong, but I think Spots suggestion only works on a Windows Media File. If you can get a Windows Media File to your TV, you might see the CC.

Again, I may be in error.

Dave T2