MP4 to 3GP Converter

3GP is the video format of feature phones and early smartphones: small pictures, low frame rates and compact files that old handsets, some car systems and kids' phones still need. This converter shrinks any video to a 3GP with H.264 Baseline (the profile simple phone decoders handle) or, for the oldest models, H.263 at the standard 176 × 144 or 352 × 288 sizes, with AAC sound. It runs in your browser with the ffmpeg engine (about 30 MB, downloaded once); the video is never uploaded.

How to use this tool

1. Choose one or more videos (MP4, MOV, MKV, AVI and others).
2. Pick H.264 Baseline unless the phone is very old, then the picture size its screen uses.
3. Choose a frame rate (15 fps keeps files small) and mono or stereo sound.
4. Download the .3gp files and copy them to the phone.

Formula

Size fitted inside the box: scale = min(1, box width ÷ width, box height ÷ height)

The picture keeps its shape, uses square pixels and is never enlarged; portrait videos are fitted into the box turned upright. H.264 is encoded with the Baseline profile at level 3.0, which allows up to 720 × 480 at 30 fps. H.263 only knows a few fixed sizes, so the picture is fitted into 176 × 144 or 352 × 288 and padded with black. Sound is AAC-LC: the in-browser engine has no AMR encoder.

Example

A 1920 × 1080 phone clip with the 320 × 240 setting: scale = min(1, 320 ÷ 1920, 240 ÷ 1080) = 0.1667, giving 320 × 180. At 15 fps and with 48 kbps mono sound, a minute of video is typically 1.5–3 MB.