LRV, THM and LRF files: what GoPro, DJI and Insta360 cameras leave on your Mac, and whether they matter

Copy a GoPro card to your Mac and next to each .MP4 there is an .LRV file and a .THM file. DJI drones and cameras write .LRF files, and Insta360 cameras write their own LRV_ files. The question everyone asks is whether they can be deleted. The more useful question is how much they actually cost, because it is usually less than you think.

What each file is

Measure before deleting anything

cd /Volumes/YourCard/DCIM   # or the folder you imported into
for e in MP4 LRV THM LRF INSV; do
  printf '%-5s ' $e; find . -iname "*.$e" -print0 | du -ch --files0-from=- 2>/dev/null | tail -1
done

If du on your Mac does not accept --files0-from, this works everywhere:

find . -iname '*.LRV' -exec du -ch {} + | tail -1
find . -iname '*.MP4' -exec du -ch {} + | tail -1

On most cards the low resolution copies are a small fraction of the full clips. Deleting them is tidy, not a rescue. The space is in the footage itself.

Where the space really goes

• High resolution, high frame rate modes. Higher settings write much more per minute. Our guide to how much space 4K video takes per minute has the arithmetic.
• Clips split into chapters. Long recordings are split into several files, each a few gigabytes. They add up without looking like one big file.
• Imports kept twice. A desktop app that imports into its own library while the original folder stays in Downloads or on the Desktop. Search for duplicates by name and size before buying a bigger drive.
• 360 degree footage is stored as two lenses' worth of video and exported flattened copies, so each clip can exist in two or three forms.

If you do remove the preview files

They are safe to remove from a copy on your Mac. Do not remove them from the card while you still want to play clips back on the camera, since the camera uses them for its own screen. Moving them to the Trash keeps them recoverable until you empty it:

find ~/Movies/GoPro -iname '*.LRV' -o -iname '*.THM' | head   # check the list first

For the bigger picture of video on a Mac, see storage for video editors.