.cm0013 file, created by select Samsung Smart TV is an index to the files located on external storage medium, such as a USB flash drive. The file is a pointer to the actual location on the disk of video data, similar to the
.cda file on an audio CD, and is not the video data itself.
Look for other files on the USB drive, since clearly, something is taking up about 4.4 GB of the ~8 GTB on it. The drive might have hidden files, or even another partition, which you are not seeing in File Explorer. Turn on
Show hidden files, folders and drives. Also try searching using
Press Windows, type
cmd and press CtrlShiftEnter to get a CMD dialog as Administrator.
f: and Enter to move to the F: drive, assuming that is where the USB flash is shown.
dir \a:h and Enter to find hidden files.
dir \a:i and Enter to find un-indexed files.
dir \a:s and Enter to find system files.
dir \a:d and Enter to find other folders (directories).
If the video file still is hidden, it might be on another partition, which you can view in Disk Management: Press Windows, type
diskmg in the Search box and select diskmgt.msc.