Iv'e taken this info from a Vix epg refresh pdf.
EPG from the signal stream
Enigma2 can gather the EPG data directly from the signal stream for several providers.
OpenTV EPG used by some providers like Sky UK/IT has been added to OpenViX/OpenPLI in August 2019. (Thanks to LraiZer)
This means that just by zapping, watching, viewing or “turning to” a channel, the EPG data will be added to your Enigma2
receiver.
There is no need to use plugins, download from the internet, maintain a database of service references etc.
As the number of channels varies between providers, some providers limit amount of EPG on the normal frequencies.
They keep the vast amount of data on a specific frequency. If we zap/select/view any channel on that frequency, the EPG data will
be added/absorbed into the EPG cache on the system.
This needs to be done regularly to maintain the data.
UK Freeview (Aerial): You can use any channel
Virgin UK (Cable): “PVR_EPG” or any service on the frequency.
Sky UK (28.2): “IEPG data 1” or any other service on 11778, V, 27500
I do not use epg refresh I did try it to see if Freeview channels would populate with it but no joy still had to select a channel before it would populate.