What is a 3GP file?

What 3GP is

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.

Where 3GP came from

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.

The specification is public

Anyone can implement it without asking permission or paying a licence, which is why it turns up in so many programs and why files written twenty years ago still open.

It is a legacy format

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.

3GP is a box, and the codec is what is in it

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.

What else it can carry

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.

What opens 3GP

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.

Opening it in a browser

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.

It is a delivery format

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.

What goes wrong with it

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 facts, in one place

Formats worth considering instead of 3GP

• MPEG-4 Video