I was mostly considering the American market here since the real distinction may be what can get carried on cable. And I think that varies quite a bit based upon governmental regulations.
I'm actually wondering what a station might get away with placing in the advanced caption info before cable wouldn't carry it anymore.
- Tom Russ Wood wrote:
Tom, what geographical limits do you want to apply to the answer - this is a view from Europe. For example in the UK there are subtitles/captions (can be multi-language, bitmap not character coded), audio description, DSM-CC carousel carrying an MHEG-5 application and its data replacing the teletext service. In the rest of Europe the bitmapped subtitles are often replaced by a teletext stream (coded as bytes of data replicating the whole teletext VBI), if there is a digital application it will most often be a DSM-CC carousel of MHP application and data. Open-TV based systems have a different application environment. There are often streams carrying private data for an EPG - for where the EIT tables aren't good enough. Most transport streams are multi-channel, carrying 4 or more SD videos plus the above, themed channels may share capacity and switch over at a particular time of day. An inactive channel may carry an application as a place-holder. Support for audio description was sparse until about a few months ago when Sony and Panasonic both launched new ranges of ITDVs which had AD built in. Most STB and IDTV support the MHEG-5 application environment. Where the STB is not bound by the broadcaster to a particular EPG the receiver will have at least a rudimentary EIT based EPG but which may not have the luxury of lots of cache. Regards - Russ Wood -----Original Message----- From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] On Behalf Of Tom Barry Sent: 02 May 2008 12:43 To: opendtv Subject: [opendtv] Carriage of various extra types of data in digital TV Digital TV was spec'd out with the ability to have multiple sub-channelsplus various extra non-AV types of data in each stream. Is there any consensus about what types will usually be carried on cable orsatellite? I'm guessing that multi-must-carry will not come about and that any typeof PSIP or caption data probably WILL be carried, no matter what's in it. Anyone disagree? What about other types of data that can be embedded in the primary program stream? Anybody know the current FCC stance? Or even current common practice?This could pretty much set the standard of what actually gets used since broadcasters these days seem to mostly care about cable carriage and may not invest practically anything for antenna-only material. Also, anybody know what current integrated digital TV's usually support? - Tom
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