Dear Freesurfer experts,

I tried to run Recon-all on a T1 series .nii file. A error occurred:  "ERROR: input(s) cannot have multiple frames!". I tried to google the method of converting multi frame dicom to single frame dicom. I found software of  "dicom2" stated that it could perform the conversion but their manual guide are too hard for me to understand. May I know there are any easier method to perform the conversion? Thank you.