the unit calculates a recording rate that enables the recording to fit in the time you set (within the remaining time on the disc) and with the best possible picture quality.
1 while stopped
press [f rec].

it may not be possible to record to the finish of the program if the remaining time doesn’t allow.
for your reference
1 press [status] during recording to show the remaining time.
2 recording time reduces if you repeatedly pause recording.
3 the recording mode becomes fr.