I never had to patch my VDR to make it play NTSC properly. Have you ever
tried the videosystem plugin? I have been using it for quite some time
and it always worked flawlessly. It can be found here:
http://www.vdr-portal.de/board/thread.php?threadid=43516

VDR will play video fine w/o patching the code. But, the improper framerate will calculate incorrect times on the video. Also, the OSD will be sized differently when 720x480 is used instead of the hardcoded value of 720x576.

Regards.