[mythtv-users] EIT data

Daniel Kristjansson danielk at cuymedia.net
Wed Jun 20 19:29:54 UTC 2007

On Wed, 2007-06-20 at 14:45 -0400, Tom Lichti wrote:
> Matt Mossholder wrote:
> > Given all the discussion around Zap2it today, I was thinking that maybe
> > looking into using EIT would be a good thing. However, I am having
> > trouble coming up with answers to some of my questions. If anyone out
> > there can fill me in, I'll consolidate the answers and ensure they make
> > it into the Wiki's EIT page.
> >
> > Here goes...
> >
> > 1) Is EIT information available for analog channels, or is it only
> > available in DVB/ATSC/MPEG-(TS? PS?) streams?
> AFAIK, in Canada anyway, there is no EIT info on analog channels.

EIT can be used to provide guide data for analog channes, but
PBS is the only broadcaster I know of that does this in the USA.
And they only do it for their own analog channel. MythTV doesn't
use this data, but it wouldn't be hard to do if there is a need.

> > 2) For non-satellite transmissions, does each channel have to be tuned
> > to gather EIT? Can it be gathered per-Transport Stream, or does each
> > channel have to be tuned individually?
> Unknown, but the data probably isn't there.

I think this depends on the network. Some do it per transport
others have one transport with all the guide info.

> > 3) Do some cable providers perform some sort of aggregation like the
> > satellite providers?
> I believe so, for digital cable there must be a 'listings' channel, 
> otherwise how would the EPG know what data is available? I think Silicon 
> Dust (the developers of the HDHR) are trying to figure out the streams 
> on that channel for SA headend networks.

In North America I think this data is usually transmitted
out-of-band using a QPSK modulation which is not supported
by any consumer DTV card. In Europe it is usually transmitted
in-band and people there have been enjoying much more complete
EIT listings for a while now. For OTA channels in the US the
cable operators are required to pass along at least some of the
EIT info that the broadcaster provides, but I read somewhere
that some cable operators interpreted the must carry to apply
only to the limited EIT that broadcasters are required to
provide, not the full 16 days of EIT data they can optionally
provide. So as always for HDTV, you may have better luck with
an antenna than with a cable feed.

-- Daniel

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