LRV File Documentation
Summary
An LRV file is a Low Resolution Video: a small, low-quality proxy copy of a clip your GoPro or DJI camera recorded next to the full-quality .mp4. It is technically just an MP4 with a different extension, so it plays in VLC, or you can rename it from .lrv to .mp4 and open it in any player. Cameras create it so phone apps can preview and edit footage quickly. Its MIME type is video/mp4. For the real high-quality video, use the matching .MP4, not the .LRV.
Technical details
| Feature | Value |
|---|---|
| Full name | Low Resolution Video (GoPro / DJI proxy clip) |
| File extension | .lrv |
| MIME type | video/mp4 |
| Format type | MPEG-4 video in an MP4 (ISO Base Media) container |
| Actual format | An ordinary MP4 with a renamed extension |
| Developer | GoPro (also DJI and other action cameras) |
| Introduced | GoPro HERO era, ~2014 onward |
| Base format | ISO Base Media File Format (ISO/IEC 14496-12) |
| Open standard | Yes (the underlying MP4 is an ISO standard) |
| Byte order | Big-endian |
| Magic number | 66 74 79 70 (ftyp) at offset 4 |
| Video codec | H.264/AVC |
| Audio codec | AAC |
| Typical resolution | Low, roughly 240p–480p |
| Purpose | Fast preview and proxy editing on phones/low-power devices |
| Created automatically | Yes — alongside every full-resolution clip |
| Paired files | Full-quality .MP4; often a .THM thumbnail |
| Safe to delete | Yes, once the real .MP4 is offloaded |
| Related extensions | .mp4, .thm, .mov, .360, .lrf |
What is an LRV file?
LRV stands for Low Resolution Video. It is a proxy file that GoPro action cameras, and DJI drones and Osmo gimbals among others, record automatically next to every full-resolution clip, starting in the GoPro HERO era around 2014. When a GoPro records a 4K video as, say, GH010123.MP4, it simultaneously writes a small GL010123.LRV holding the same footage at a much lower resolution, typically around 240p to 480p, and a low bitrate. The camera and the GoPro Quik phone app use this lightweight copy so you can scrub, preview and rough-cut on a phone without struggling with a huge 4K or 5.3K file; the app then applies your edits back to the full-resolution MP4.
The single most useful fact about the format is that an LRV is not a special format at all. It is an ordinary MP4 file (H.264 video with AAC audio in an ISO Base Media container) that GoPro simply gave a different extension. Everything technical about an LRV is therefore MP4 technical detail, and the sections below go into that structure: how to confirm it is an MP4 from its first bytes, the box hierarchy inside it, why the rename trick works losslessly, how it pairs with the full clip and the thumbnail, and when it is safe to delete.
The ftyp box: proof it is an MP4
You can confirm an LRV is an MP4 by looking at its first eight bytes. An ISO Base Media file does not start with a magic number at offset 0; instead it starts with a box, and every box begins with a 4-byte big-endian size followed by a 4-byte type. So bytes 0–3 are the size of the first box (commonly 00 00 00 18 or 00 00 00 1C), and bytes 4–7 are the ASCII characters ftyp (66 74 79 70), the file-type box.
offset 0 00 00 00 1C size of the ftyp box (28 bytes)
offset 4 66 74 79 70 'ftyp' (file-type box)
offset 8 XX XX XX XX major_brand, e.g. 'mp41' or 'avc1'
offset 12 00 00 00 00 minor_version
offset 16 ... compatible_brands listThe four bytes after ftyp are the major brand, which names the MP4 flavour the file conforms to. This is the same marker used by MP4, MOV, .m4a and .3gp, all of which share the ISO Base Media File Format. Because the identifying ftyp sits at offset 4 rather than offset 0, the .lrv extension is the only thing telling your operating system not to treat the file as video; the bytes themselves are pure MP4.
The box hierarchy inside an LRV
An LRV has the same box (or “atom”) structure as any MP4: a flat sequence of nested boxes, each starting with its own size and type, so a player can walk the tree and skip anything it does not recognise. Three top-level boxes matter.
ftyp file-type box: brands / MP4 compatibility
moov movie box: all metadata, no media
└ trak one track (the low-res video), plus an audio trak
└ mdia > minf > stbl the sample tables that index the frames
mdat media data box: the actual low-res H.264 frames and AAC audioThe moov box holds the metadata: track definitions, duration, the codec configuration and the sample tables (stbl) that map each frame to a byte range and a timestamp. The mdat box is the opaque blob of coded video and audio. Nothing inside mdat is self-describing; it is meaningless without the moov index pointing into it. A fuller box-by-box description of this structure is on the MP4 page, and it applies unchanged to an LRV, because an LRV is an MP4. The only practical difference from the full-resolution clip is the numbers: a small frame size, a modest frame rate and a low bitrate, which is what makes the proxy tiny.
Why renaming .lrv to .mp4 works losslessly
Because the container and codecs are already standard MP4, the fastest way to make an LRV usable is to rename it. Enable file-name extensions in your file manager, then change clip.lrv to a new name ending in .mp4. The bytes on disk do not change at all; you are only changing the label that tells the OS which player to hand it to. After the rename it opens in Windows Media Player / Films & TV, QuickTime, the Photos app or anything else, exactly like the file it always was.
Two cautions. First, give the renamed file a new name. The full-resolution clip and its proxy share a stem (GH01xxxx.MP4 versus GL01xxxx.LRV), and if you rename the proxy to the full clip’s name in the same folder you can overwrite your real high-res footage with the low-res copy. Second, the rename does not improve quality: the proxy contains only low-resolution frames, and no tool can reconstruct the detail that was never recorded into it. If you prefer not to rename, play it directly in VLC, which ignores the extension. For a clean re-wrapped copy without re-encoding, ffmpeg -i in.lrv -c copy out.mp4 stream-copies the same bytes into a properly labelled MP4.
The clip file set: MP4, LRV and THM
When you copy a GoPro or DJI SD card to a computer you see clips arriving in sets rather than as single files. For one recording there is typically a large .MP4 (the full-quality video), a small .LRV (this low-res proxy) and often a .THM (a small JPEG thumbnail the camera writes for previews). They share a numbering scheme so the camera and app can match them: GoPro names the full clip GH01xxxx.MP4 and its proxy GL01xxxx.LRV, differing by the GH/GL prefix on the same clip number. On the camera itself the proxies are normally hidden, which is why they seem to appear from nowhere only once you offload the card.
If you ever find only an .LRV and no matching .MP4, the full clip probably did not copy across, or the recording of the high-res file failed. Re-check the SD card for the GH-prefixed file before assuming the footage is lost, because the proxy on its own is only the low-quality version.
Deleting LRV files and using them for proxy editing
LRV files are ordinary MP4 video with no executable content, so they are safe both to open and to delete. Once you have copied the real high-resolution .MP4 clips off the camera, the .LRV proxies (and the .THM thumbnails) are safe to remove and will free a useful amount of space. The only real hazard is the rename mistake above: reusing the full clip’s name and overwriting it.
The one reason to keep the proxies is proxy editing. Editing 4K or 5.3K footage on a phone or an older laptop is heavy; a low-resolution proxy lets you cut, arrange and preview smoothly on modest hardware, after which the editor relinks to the full-resolution files for the final render. That is exactly the workflow the GoPro Quik app automates with these files. If you do not edit that way, you lose nothing by deleting them. Finally, ignore “LRV converter” download sites: since the file is already an MP4, VLC, the rename trick, or FFmpeg and HandBrake do everything for free, and those “converter” sites are a common source of bundled adware.
References
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