Im interested in understanding a bit more about EPGs on BT Vision/Virgin/Sky/Talk Talk TV etc etc. I dont have access to any of the hardware yet - but am looking at trying to buy some second-hand equipment.
My assumptions are as follows. All boxes require a broadband connection. So my understanding would be that the EPG would be delivered over the Internet. Connecting to a web service that delivers back maybe an XML file that is more than likely encrypted and stored on hard drive. This EPG would be updated probably at boot up of the box and when TV Guide requested. This is different with Sky as it has no broadband connectivity so the EPG must be delivered over satellite.
I suppose can anyone confirm if this is correct for any of the mentioned platforms. I would be interested to hear about anyones experiences with EPGs. Are the EPGs encrypted at all? Has anyone put ethereal or similar on the back of one of the boxes? If so would they mind sharing their information.
If I remember correctly, the bt box uses a large binary blob of data wrapped up in an xml file.
This may be of use if you are interested in the sky EPG algorithm.. Not sure if this is still the way its implemented.
http://steventoth.net/ReverseEngineering/BSKYB/skyepg_algo.c
Mick