What is a 3GP file?

3GP is a container: a wrapper that holds streams encoded by something else. It is used for phones.

The extension is .3gp, and the full name is 3GPP Multimedia. Both matter less than what the file can hold, which is what the rest of this page is about.

3GPP published it in 2001.

Age is worth knowing here for one practical reason: the older a format is, the more programs have had time to learn it.

It is published in full, so anyone can implement it from the document rather than by inspection, which is why it turns up in so many programs and why files written twenty years ago still open. A published specification is not the same thing as a royalty-free one: where a format wraps a codec, the patent licensing is a separate question the standard does not settle.

It still opens everywhere and is still written by older tools, but nothing new is being built around it. Convert what you mean to keep, and do not choose it for something starting today.

It usually holds H.263, H.264 and AMR. This is the distinction behind most "why will this not play" questions: two files with the same extension can contain entirely different encodings, and a player that refuses one may be perfectly happy with the other.

It also explains why changing container is often fast and lossless while changing codec is neither. Moving the same stream into a different box rewrites the box; re-encoding rewrites the picture.

3GP can hold several audio tracks and a layout that lets it start playing before it has finished arriving.

That matters mostly when converting: whatever the target cannot hold is dropped, usually without a warning.

VLC and FFmpeg read it, and so do most programs of the same kind.

If a file will not open, the format is rarely the problem — it is more often that the program predates it. Converting to something older is the reliable way past that, and it is what the rest of this site is for.

Only some browsers read it.

Where support is uneven, serving a second format alongside it is the usual answer — the browser takes the one it understands and nobody is left out.

3GP is meant to be handed over rather than worked in. Editing one is possible and rarely pleasant; the sane approach is to change the source and export again.

The recurring complaints: support outside its home ground is uneven.

None of these is a reason to avoid the format. They are the things worth knowing before you are surprised by one, which is a different claim and a more useful one.

The 3GPP consortium defined 3GP in 2001 for mobile networks that measured bandwidth in tens of kilobits. It is a cut-down relative of MP4 — the same container family, restricted to the codecs a phone of that era could decode without help and a network of that era could carry.

So the files that exist are the video people shot between roughly 2003 and 2010: on a Nokia, a Sony Ericsson, an early BlackBerry, a flip phone. They surface now from memory cards, old backups, and the folder somebody copied off a phone before throwing it away.

Typically 176 by 144 pixels, sometimes 320 by 240, at ten or fifteen frames a second, with speech-optimised audio at a few kilobits. That is smaller than a modern thumbnail and it is not a fault in the file — it is what the hardware recorded.

This matters because people arrive hoping a conversion will improve it. Nothing can. The detail was never captured, and enlarging the frames produces a blurrier version of the same picture. What conversion buys is a file that plays; what it cannot buy is a better recording.

Support has quietly evaporated. Browsers do not play 3GP, phone galleries generally do not, Windows Media Player does not, and most current editors will not import it. VLC does, and so do a few other players built around a broad codec library.

The cause is the codecs rather than the container: H.263 and early MPEG-4 video with AMR speech audio are formats nothing has shipped support for in years. Which is precisely why converting is usually the only route to watching the footage at all.

MP4 with H.264 is the target. It plays on every phone, television, browser and computer with nothing installed, and it will still do so in a decade — which is the whole point for footage that has already survived one format transition.

Keep the original resolution rather than upscaling. A 176 by 144 video enlarged to 720 is the same picture, softer, in a file five times the size, and it also makes the footage look worse on a modern screen than letting the player scale it. Convert once, at a generous bitrate so the encoder does not add its own damage on top, and keep the source files.

These recordings carry AMR, a speech codec that models a human vocal tract rather than a signal. Voices come through recognisably; music, room ambience and anything not a person talking come through badly, because there is no vocal tract to model.

Nothing recovers that either, and converting to a better audio codec preserves exactly what was captured. It is worth knowing before somebody is disappointed that a recording of a school concert is unlistenable — the phone was never able to record it properly.

3G2 is the same idea for CDMA networks — American carriers of the period — and differs in a few details and in which codecs it permits. The same tools read both, and the same advice applies.

MP4 is the parent standard, and the reason a 3GP sometimes plays where it is not expected to: the container is closely enough related that some software treats it as an MP4 with unusual contents. When a player accepts one and refuses another, renaming to .mp4 is worth trying before anything else.

Copy the whole card or backup folder rather than picking out files, because the video often sits alongside a thumbnail and sometimes a separate audio file, and the date is frequently only in the file name or the folder structure.

Then convert a couple of files and look at them before converting hundreds. And record the dates somewhere durable while you still have the original folder — a converted MP4 carries whatever date the conversion wrote, and a family archive that will not sort chronologically is a great deal of work to repair later.