3GP to MP4 Converter

3GP is the video format of 2000s mobile phones: small clips with H.263 or MPEG-4 video and AMR sound tuned for speech. Today most players, editors and phones ignore those codecs. This converter re-encodes old 3GP and 3G2 clips to H.264 video with AAC sound in an MP4 that plays everywhere, and copies newer 3GP files that already hold H.264 and AAC without re-encoding. Tiny 176 × 144 or 320 × 240 clips can be enlarged 2× with a sharp Lanczos filter. It runs in your browser with the ffmpeg engine (about 30 MB, downloaded once).

How to use this tool

1. Choose one or more .3gp or .3g2 files.
2. Keep "Fastest" (H.264 clips are copied, others re-encoded), or choose "Always re-encode".
3. Optionally enlarge tiny clips 2×.
4. Download the MP4 files.

Formula

H.263 / MPEG-4 + AMR → H.264 (CRF) + AAC; H.264 + AAC → copied

AMR-NB sound is narrow-band speech sampled at 8 kHz; it is converted to AAC at the same rate (48 kbps), which keeps everything that is there — re-encoding cannot add the high frequencies the phone never recorded. Enlarging uses Lanczos scaling and only applies to clips up to 400 px on each side.

Example

A 176 × 144 clip from a 2006 phone, 40 seconds at 15 fps, re-encodes in a few seconds; enlarged 2× it becomes 352 × 288, which looks less blocky when played full screen. A 3GP from a 2012 Android phone with H.264 and AAC is simply repackaged.