Convert · runs on your device

Convert 3GP to MP4 in your browser

Video Mender converts 3GP to MP4 by copying the video stream where it can and re-encoding the AMR speech audio to AAC — which is what actually stops these old clips from playing today.

Nothing is uploaded

Drop video files here

3GP

Choose video files to convert

Output format

Plays on effectively every browser, phone, TV and editor when it holds H.264 and AAC.

Video codec

The universal baseline. Hardware decoding exists on essentially every device sold since 2010.

How to size the output

A constant quality target. File sizes vary with how demanding the footage is.

Quality — 8 of 10

Resolution limit

Files smaller than the limit are left alone. Capping usually looks better than lowering the bitrate.

Frame rate

Audio

Fast rewrapCopy streams without re-encoding when the codecs already fit

Lossless and near-instant when it applies. It cannot reduce file size, so turn it off if you need a smaller file.

3GP is the mobile container from the era before smartphones: same ISO base structure as MP4, but holding low-resolution MPEG-4 or H.264 video and, crucially, AMR narrowband audio — 8 kHz speech compression designed for phone calls.

The AMR audio is usually the real problem. Modern players will often show the picture from a 3GP file and stay completely silent, because AMR is no longer supported. Video Mender re-encodes the audio to AAC while copying the video stream where the codec permits, so the clip becomes playable without the picture being touched.

Expect the resolution to be small — 176×144 or 320×240 is typical of this generation. That is faithfully preserved. Upscaling would inflate the file without adding a single pixel of real detail, so it is deliberately not the default.

What this actually does to your file

Rewrap or re-encode

Video copies when the 3GP holds H.264 or MPEG-4, which covers most files. Audio always re-encodes when it is AMR, because MP4 players do not reliably support it.

Quality

The video is copied unchanged whenever the codec allows, so the picture does not degrade. AMR audio is re-encoded, which cannot add back the fidelity 8 kHz speech compression discarded.

These clips are genuinely low resolution. Converting makes them playable, not sharper.
AMR audio re-encoded to AAC still sounds like 8 kHz speech — the source fidelity is the ceiling.
Some very old 3GP files use H.263 video, which needs a full re-encode; the queue will say so.

How to use this page

Add your .3gp or .3g2 files.
Leave audio set to AAC — this is the setting that makes the clips audible again.
Keep resolution at source; upscaling old phone video is not worth the bytes.
Start and download the MP4 files.

Where the result plays

Checked against the containers and codecs this page produces, stated conservatively.

Target	Works	Detail
Phones and tablets	Yes	MP4 with AAC plays and shows in the gallery; 3GP with AMR often plays silently.
Browsers	Yes	MP4 plays inline. 3GP support is inconsistent and the audio usually fails.
Video editors	Yes	MP4 imports normally. AMR audio is rejected by most editors.
Old feature phones	No	If you need playback on period hardware, keep the original 3GP.

The formats involved

Format	Read	Write	What it is
3GP	Yes	Yes	The 3GPP mobile container from the pre-smartphone era. Same ISO base structure as MP4, usually holding low-resolution MPEG-4 video and AMR narrowband speech audio.
MP4	Yes	Yes	The MPEG-4 Part 14 container. It is a wrapper, not a codec — an MP4 usually holds H.264 or HEVC video with AAC audio.
MKV	Yes	Yes	Matroska. The most permissive common container: it will carry almost any codec, plus multiple audio tracks, chapters and subtitles.
WebM	Yes	Yes	A deliberately restricted Matroska profile for the web: VP8/VP9/AV1 video with Opus or Vorbis audio, and nothing else.

Tested limits

Real ceilings measured on real devices, not a marketing claim of unlimited.

Limit	Desktop	iPhone / iPad	Why
File size — rewrap	1.3 GiB	384 MiB	Rewrapping never decodes a frame, so it tolerates far larger files.
File size — re-encode	1.0 GiB	256 MiB	Decoding holds uncompressed frames in memory, which is the real constraint.
Clip length — re-encode	4:00:00	30:00	Beyond this, progress reporting and memory behaviour stop being dependable.
Resolution — re-encode	4096 × 2160	1920 × 1080	A 4K frame is about 12 MB decoded, before the encoder allocates anything.

If something goes wrong

The original had no sound and the MP4 has none either.

Then the source genuinely has no audio track, which the file inspector will confirm. Conversion cannot create audio that was never recorded.

The video looks blocky and soft.

That is the source. 3GP was encoded for 2G bandwidth at tiny resolutions; converting preserves it faithfully but cannot improve it.

The file was marked as needing a full re-encode.

It probably contains H.263 video, which MP4 cannot carry. The re-encode to H.264 is automatic and quick at these resolutions.

Your video never leaves this device

This is a structural property of the application, not a policy we ask you to take on trust. There is no upload endpoint, no API route and no server action anywhere in the codebase, so there is nowhere for a video to be sent even by mistake.

Conversion runs in WebAssembly inside this browser tab. The engine is served from this domain and loaded only when you start a job.
The Content-Security-Policy restricts network connections to this origin, so the page is not permitted to contact a third party at all.
Nothing is stored. Close the tab and every queued file and finished output is gone — which is also why you should download results before you leave.
There are no accounts and no AI. Anonymous page views are counted — which page, roughly what country, what kind of device — and nothing whatsoever about your files.

The repository contains a test that fails the build if any media byte is passed to fetch, XMLHttpRequest, sendBeacon or a WebSocket. See the privacy page for how that is verified.

Questions

Why does my 3GP play with no sound?

Almost always AMR narrowband audio, which current players no longer decode. Re-encoding the audio to AAC — which this page does by default — restores sound.

Is 3GP the same as MP4?

They share the same ISO base media structure, but 3GP restricts which codecs may appear and adds mobile-specific ones like AMR. That codec restriction is why a plain rename does not reliably work.

Can conversion improve the quality?

No. Nothing can recover detail the original encoder discarded. Conversion makes the clip playable on current devices; it does not make it look better.

Should I upscale to 720p?

There is no benefit. Upscaling multiplies the file size while inventing no real detail. Leave the resolution at source and let the player scale on screen.

Is my old footage uploaded anywhere?

No. Old phone videos are usually personal, and this tool processes them entirely inside the browser tab with no network transfer of media at all.