HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Media Center\Service\Video\Tuners\DVR
Click once on the DVR key to display the values on the right panel.
Find theBackingStoreEachFileDurationSecondsvalue on the right side.
Double click onBackingStoreEachFileDurationSecondsto fire up the Edit DWORD Value window.
The default buffer time is 40 minutes, or 2400 seconds.
Here’s a quick little conversion chart to ease the calculating.
