From VDR Wiki
Digital receiver devices
VDR supports DVB and ATSC digital tuner devices. Analogue tuner cards can be used also. DVB tuners are used in Europe, Africa, Australia and some parts of Asia including India and excluding China. ATSC tuners are used in USA and Canada.
Analogue tuner users may enter some text here.
ATSC tuner users may enter some text here.
VDR needs a DVB tuner for receiving TV signal from satellite, cable or terrestrial transmitter. DVB-S card is for receiving digital signal from satellite, DVB-T is for receiving digital signal from terrestrial transmitter and DVB-C is for receiving digital signal from cable. VDR can also use analogue cards. It is also possible to receive signal with VDR server and stream it to the client. DVB-C2, DVB-T2 and DVB-S2 tuner devices basicly mean devices capable of receiving HD content.
There are many of kind tuner cards to choose from. There are PCI, PCI-e and USB cards available. V4L-DVB Wiki has good list of cards at http://www.linuxtv.org/wiki/index.php/Hardware_Device_Information