GoPro LRV and THM Files: What They Actually Do

When you go to download a video file from your GoPro’s memory card, you might have noticed that there are some extra files alongside your MP4 video file. They have the same filename but a different extension.

These files aren’t just clutter, though. They’re what the camera and the Quik app lean on to show you a preview of a clip, which is why it’s worth knowing what they do before you assume something else has gone wrong.

The files you’ll see on GoPro models are LRV and THM files. Both of these file formats are created automatically by the camera and are used by the GoPro mobile app, Quik, as well as the camera itself.

So do you need to keep those files? And are they important? Here is an explanation of what they are and why they’re there.

What are GoPro LRV and THM files?

LRV stands for Low-Resolution Video: a small proxy copy of your clip, recorded at a fixed 240p regardless of what resolution you actually shot in. It lets you preview footage smoothly on your phone or on the camera’s own screen, without the processor choking on the massive high-resolution master file.

THM stands for Thumbnail. These are small JPG thumbnails used to display the grid of images in your gallery.

Worth knowing: You can safely delete both file types. It will not delete your actual video. However, doing so will break the ability to play back that video on the camera or preview it in the app until the files are regenerated.

What is a .LRV file on GoPro?

The file extension .LRV stands for Low-Resolution Video.

The reason these are used rather than the original MP4 videos comes down to filesize and processing power. GoPro uses the MP4 file extension for both H.264-encoded video and H.265 HEVC-encoded video.

The high-resolution master files that the GoPro shoots are massive. For instance, one minute of 5.3K video at a high bitrate can generate a huge amount of data. Decoding that on the fly — especially over Wi-Fi to a phone — is difficult.

Trying to stream that full-resolution master file to your phone app would cause buffering, stuttering, and massive battery drain. Furthermore, even the camera’s own rear LCD screen often uses the LRV file for playback because it’s more efficient than decoding the full 5.3K master file just for a small preview.

The LRV version is much lower resolution and bitrate.

While the master file might be hundreds of megabytes, the LRV version is typically around 20MB. That’s much easier for both camera and phone processors to work with.

If you’re familiar with video editing in Final Cut Pro or Premiere, these LRV files are essentially “Proxy files.” They offer a lightweight version of the video that you can use for editing and viewing, while the final export uses the high-quality master file.

Pro Tip: If you ever need to view the video inside an LRV file on your computer, you can simply rename the file extension from .LRV to .MP4. It will play back in any standard video player (just at a lower quality).

One thing that catches people out on recent cameras: you might not see these files at all. GoPro’s manuals for the HERO12, HERO13, MAX 2 and the MISSION series say the LRV and THM files are hidden from view. To see them on a Mac, open the folder and press Command + Shift + . (dot). On Windows, go to View > Show > Hidden Items in File Explorer.

What is a THM file on GoPro?

THM isn’t a GoPro invention, either — it’s a small-file convention other camera makers use too, including Canon, Sony, and Olympus. GoPro just leans on it more heavily than most, since its cameras and app rely on the thumbnail for every gallery grid you scroll through.

The file extension .THM stands for Thumbnail.

It is a small JPG image file, typically 160×120 pixels. It is exactly what it sounds like: the thumbnail image you see in the camera’s gallery grid or the Quik app to identify the video.

Having these pre-generated means the camera doesn’t have to scan every massive video file to generate a preview image every time you open the gallery. This makes scrolling through your media much faster.

Things worth knowing about LRV & THM files

Do you need to save LRV & THM files?

No. The MP4 files are the only ones that matter for your final video quality.

The LRV and THM contain no unique data. If you are copying your files to a hard drive to edit on a computer, you can leave the LRV and THM files behind. You only need to drag the .MP4 files over.

What happens if you delete the GoPro LRV & THM files?

On the HERO13 Black and other recent models, this is also the mechanism behind a real Quik app bug: if the camera fails to write LRV and THM files for a clip in the first place (rather than you deleting them afterward), the app has nothing to build a preview from and “Enable Preview” and “View Media” can show a black screen or an empty gallery even though the footage is safely on the card.

If you delete them from your SD card while you are still out shooting, you can lose the ability to play the clip back on the camera’s own screen. The file is still there, but the camera leans on that lightweight LRV proxy for playback rather than decoding the full-resolution master.

If you use the Quik mobile app, the app is smart enough to regenerate them. If the files are missing, the app will offer to generate a new proxy version so you can edit. This takes time and battery power, but it will work. (Note: The camera itself will not regenerate them on the SD card; only the app does this).

The screens below come from that regeneration step in the Quik app. It’s worth reading the wording closely, because it points at something slightly different: the app says your phone doesn’t support the recorded resolution, so it is building a version the phone can play. A phone that can’t decode 5.3K or HEVC lands on that same Generate Video button even when the LRV and THM files are sitting right there untouched.