It kind of "screen scrapes" - it looks at a web page containing TV information like this and tries to rip the text off it and convert it into an easy to use format.
When it does work, this will make it much easier as XMLTV can be abandoned, for DVB-T anyway (still needed for analogue, which is sound and video only) One downside of the DVB-T EPG is that it only goes 7 days into the future, whereas XMLTV does 14 days.
This is useful if you want to record when you are on holiday.
If your grabber isn't available in the package in community, you have to try and compile xmltv yourself.
You can choose between two ways of obtaining a self compiled xmltv installation.
You can use ABS and edit the PKGBUILD to make a package or compile it by hand. The script will tell you, which grabber isn't supported and why.
Refer to the wiki page about the Arch Build System (ABS) on how to use it. Now you have to check, why your grabber isn't available. You will have to install additional dependencies then.For the grabber "tv_grab_eu_epgdata" for example you will have to install perl-datetime-format-strptime from AUR. Systems like Video Plus in the UK, where numbers encode start and stop times, have made programming easier, but it's much easier to just look at an EPG and click on the programme you want to record.However, there is no central system for acquiring TV programme data, at present, so that's where XMLTV comes in.XMLTV's job is to take program data off the internet and convert it to a standard format for PVRs like Myth TV and Free VO.The problem with XMLTV is it is grabbing data from places that weren't really designed to supply it.