(Event Information Table) is extra data that is broadcast with a television signal, much like Closed Caption Text in the VBI stream. EIT provides program data for the current show and future shows which can be then used to view on-screen program information, such as title, length, description and more. This can also be gathered to build a program guide for current and future shows on all your available channels. MythTV uses an Electronic Program Guide
, or EPG. Most cable and satellite services do. Even many modern digital televisions can have a program guide by gathering and storing EIT.
EIT is typically available over digital television signals, either terrestrial, cable or satellite. With terrestrial signals, each channel provides it's own EIT. Information is usually only available for the upcoming 24 hours. With satellite, the EIT is broadcast on it's own
stream, or an Aggregate Event Information Table (AEIT), and contains information for all the channels broadcasted, and can provide scheduling
information for more than a week.
It seems that for some people EIT only works when channels have been scanned by MythTV (this has been reported to have been necessary by a DVB-T user in the UK and a DVB-C user in the Netherlands). Importing channels.conf doesn't provide enough information for MythTV to use EIT.
Howto Enable EIT Scanning
MythWeb Settings=>Channel Info
- Enable EIT Scan setting in your EPG Source (mythtvsetup)
- Tick the "useonairguide" box for each Channel you want to scan for EIT data
Note for Australian DVB-T users: Australian TV stations have recently started broadcasting upto 7 days of EIT information, (except SBS which are currently only broadcasting NOW and NEXT) therefore when using this data with MythTV and an additional EPG source is required. Often a generic title such as "SPECIAL EVENT" or "AFTERNOON MOVIE." is utilised with more infomation in the Subtitle or Description. For more information see Australian_TV_Listings.
Tip: If EIT does not appear to show in the OSD, you can try to enable EIT in MythTV 0.20 (assuming EIT is compiled in mythtv) using a channels.conf created from a program such as 'scan' (dvb-utils). Import channels.conf into mythtv-setup, then delete the channels. This will have populated MythTV with the correct transports for your transmitter/transponder (sometimes MythTV cannot find the transports on it's own). Now let MythTV do a full scan using the existing transports.
You should now have EIT showing in MythTV. Users of DVB-T (Freeview) in UK will now have the next seven days of listings available (it may take some time for the listings to build up as the EIT is scanned).
Tip: In the U.S. some digital stations may not appear in the program guide even though they are broadcasting program information. This may be due to a "hidden guide" bit that is transmitted by the stations. To see if this is the case run mythbackend with the
--verbose important,general,eit option. After some time passes check the output or check /var/log/mythtv/mythbackend.log for "is hidden in guide" output. One way to get the data to be included in the EPG is to "hack" the atscstreamdata.cpp file in libmythtv/mpeg/. Delete the code below from atscstreamdata.cpp and then reinstall mythtv from source.
VERBOSE(VB_EIT, QString("%1 chan %2-%3 is hidden in guide")
.arg(vct->ModulationMode(i) == 1 ? "NTSC" : "ATSC")
Although eit over the air is not as extensive as with Schedules Direct, it is free.
You still need mythfilldatabase Even though you may be collected listings over the airwaves, you still need to run 'mythfilldatabase' periodically in order to clear out old data from the database. This is best put in a crontab entry. If you don't do this, the system will grind to a halt because of the old, unneeded data filling up the database!