For Freeview:
EPG Data for all the channels is broadcast on each multiplex (up to 7 days of it). The EPG software on the box is made by the Set Top Box manufacturer, which downloads these listings and displays them on screen when requested.
For Sky and Cable:
It's the same principle as above, except that EPG Data isn't broadcast on every multiplex/transponder, it's broadcast on a set frequency which the Set Top Box peridoically checks (the exact intervals are unknown) and downloads. In the case of Sky (I'm not sure if it's the same for cable), it downloads the data as your on the EPG, and if it has no data on the box at all, it will say 'searching for listings' for a minute or two in which you can't use the EPG, and in some cases (especially when the box memory has been reset during a reboot), won't let you tune into any channel at all. Also, rather than each manufacturer making their own EPG software for the box, the providers (such as Sky and NTL:Telewest) make their own branded EPG software for the boxes to use (with the code adjusted for each model/varients of STB).
For freeview boxes where does the EPG information actually come from?
For Sky and other similar services where do they get their information from and who makes the software. For Sky it is NDS, but I still would like to know where they actually get the listings from.
Do they get a live feed from the TV Station owners? Is there some sort of standard system?
For freeview boxes where does the EPG information actually come from?
For Sky and other similar services where do they get their information from and who makes the software. For Sky it is NDS, but I still would like to know where they actually get the listings from.
Do they get a live feed from the TV Station owners? Is there some sort of standard system?
For Freeview/ DTT the broadcasters would do it themselves - I think it's a bit like an RSS feed. If you can't get proper listings (like here in Australia) you can go onto the internet and download them in the right format for the broadcasters which don't have more than now and next (everyone except the ABC), and upload it to your PVR/STB/whatever.
For Freeview:
EPG Data for all the channels is broadcast on each multiplex (up to 7 days of it). The EPG software on the box is made by the Set Top Box manufacturer, which downloads these listings and displays them on screen when requested.
Some Freeview boxes don't support 7 days of EPG and only offer Now & Next.
The Top-UP TV boxes, which will work with normal Freeview and the normal EPG, do support 7 day EPG, but as the boxes apparently don't work properly anyway, its not much of an incentive.
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For Sky and Cable:
It's the same principle as above, except that EPG Data isn't broadcast on every multiplex/transponder, it's broadcast on a set frequency which the Set Top Box peridoically checks (the exact intervals are unknown) and downloads.
Most Sky boxes, for the benefit of the Now & Next banner, store up to 12hrs worth of programming details, which the EPG software opens up the next batch of seemingly at 7am, 1pm, 7pm and 1am. Therefore if you use Now & Next at 6:55pm, it'll only give you details to 1am. At 7pm, you've got details through to 7am. As and when your box fetches this new data is anybody's guess, though it is possible that its a fixed time.
The full-blown EPG on the other hand varies depending on the age of the box. Some older ones download the EPG data as and when you want it and then forget it when you go back to normal viewing. Newer ones may be able to cache the data, only checking for updates if you go back into the EPG.
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Also, rather than each manufacturer making their own EPG software for the box, the providers (such as Sky and NTL:Telewest) make their own branded EPG software for the boxes to use (with the code adjusted for each model/varients of STB).
The EPG is the same whatever brand of box you have; Sky just choose to release new software versions at different times (called "staggering") for different boxes.
I
For Sky and Cable:
It's the same principle as above, except that EPG Data isn't broadcast on every multiplex/transponder, it's broadcast on a set frequency which the Set Top Box peridoically checks (the exact intervals are unknown) and downloads.
No; that's wrong for Sky.
EPG data, and software updates, are carried on every transponder that carries Sky 'platform' channels. There is the default transponder (11.778 GHz), that the Sky box will revert to when in standby, or if you hit the 'TV Guide' button. This does indeed carry EPG data, and as it carries no actual TV channels, only the EPG background musak stream, the Digiboxes are able to download the full EPG much faster than if they are tuned to any of the other t/ps .
EPG data, and software updates, are carried on every transponder that carries Sky 'platform' channels. There is the default transponder (11.778 GHz), that the Sky box will revert to when in standby, or if you hit the 'TV Guide' button. This does indeed carry EPG data, and as it carries no actual TV channels, only the EPG background musak stream, the Digiboxes are able to download the full EPG much faster than if they are tuned to any of the other t/ps .
From the technical data I've seen off my capture card, this is not the case. Only Sky operate the transponders for their channels and services (plus a few others like Disney). Most the transponders are uplinked by other satellite uplink providers (for example, ITV is uplinked by Arqiva, BBC uplink themselves). For this reason, these transponders do not carry Sky data, as Sky have no control over them. The only form of EPG Data that is uplinked on these transponders is Now and Next data for the channels, not the full 7 days listings for any channels. That is why I can be watching ITV1 and my box says it doesn't have any listings (which it does on some occasions).
EPG data, and software updates, are carried on every transponder that carries Sky 'platform' channels. There is the default transponder (11.778 GHz), that the Sky box will revert to when in standby, or if you hit the 'TV Guide' button. This does indeed carry EPG data, and as it carries no actual TV channels, only the EPG background musak stream, the Digiboxes are able to download the full EPG much faster than if they are tuned to any of the other t/ps .
From the technical data I've seen off my capture card, this is not the case. Only Sky operate the transponders for their channels and services (plus a few others like Disney). Most the transponders are uplinked by other satellite uplink providers (for example, ITV is uplinked by Arqiva, BBC uplink themselves). For this reason, these transponders do not carry Sky data, as Sky have no control over them. The only form of EPG Data that is uplinked on these transponders is Now and Next data for the channels, not the full 7 days listings for any channels. That is why I can be watching ITV1 and my box says it doesn't have any listings (which it does on some occasions).
You're quite right about the third party uplinking used by many channels, but every broadcaster still has to insert BSkyB's SI stream into their t/p uplink. To this end they have a BSkyB supplied box at their mux/code points, & this box has a data link back to Osterley. Larger broadcasters such as BBC and ITV use this same link to send their EPG data to Sky, and in the BBC's case dynamic EIT triggers etc. You could be right about the Now and Next data, but I can assure you that I've received Sky authentication signals with the box permanently tuned to a BBC channel for instance.
Am I right in saying that TV stations need to install special software and hardware that delivers their program information to set top boxes.
By the sounds of it each company may have a different system requiring the TV company to install different hardware/software. For example Sky has system, then an EPG company feeding freeview has another, then NTL has a another and so on...
Does this mean that each TV station may have several hardware/software setups to supply EPG information to different companies.
Does this also mean that the TV Station has to re-enter the data several times.
Does Sky or any EPG company have to pay the TV Station for the information?
It doesn't mean they have to enter the data serveral times, as I think all the major networks have the facility to update the EPG listings from their playout systems. As well as saving time, that way, if the schedules suddenly change (eg. Breaking News or any other last minute change), the EPG automatically updates.