Unfortunately I don't have a patch to vdr to handle this but it's better then having to install X and all the other unnecessary packages... You can compile and use v4l2-ctl from the current mercurial v4l drivers located in the v4l-dvb/v4l2-apps/util dir.
command is: v4l2-ctl -s ntsc
Tested and works. v4l2-ctl is meant to be a standalone app.