WinTV7 from Hauppauge comes with WinTV7Rec.exe as commandline based backgroundrecording tool.

There are several parameters you can use to configure this tool:

wintv7rec.exe -c:<channelnumber> -limit:<recordingtime in seconds> -prefix "<filenameprefix>"

There is a colon between the "c" and "limit"-Parameter, but a space between "prefix" and the filename!