Free online 3GP to MTS converter

A phone recording in 3GP may need conversion before an AVCHD-oriented editor, Blu-ray workflow, or camera archive can accept it as MTS. The conversion may change only the container, but older 3GP files usually also require video and audio re-encoding.

What the 3GP format is

3GP is a multimedia container developed for 3G mobile networks and low-bandwidth mobile playback. Older phones and mobile-camera applications commonly stored MPEG-4 Part 2 or H.263 video with AMR audio; newer 3GP files may contain H.264 video and AAC audio. The format is still encountered in old phone recordings, messaging software, and mobile archives.

The .3gp extension identifies a container, not one fixed codec. Resolution, frame rate, video codec, audio codec, and synchronization can vary between files.

What the MTS format is

MTS is an MPEG-2 transport-stream container commonly used by AVCHD camcorders and Blu-ray-compatible video workflows. AVCHD MTS files typically contain H.264/AVC video and AC-3 or LPCM audio at camera-compatible resolutions, frame rates, and bit rates.

MTS supports long recordings and transport-stream metadata and is accepted by some video editors, media players, and disc-authoring programs that do not support 3GP. An individual .mts file is not always a complete AVCHD recording; some applications also require an AVCHD directory structure such as PRIVATE/AVCHD/BDMV.

Convert the file on 101convert.com

1. Open the free converter on 101convert.com.
2. Upload the .3gp file and select MTS as the output format.
3. Start the conversion, then download the resulting .mts file.

This option requires no software installation. Do not upload confidential recordings unless the service's current handling and retention terms are suitable for the file.

Convert locally with FFmpeg

FFmpeg is a suitable desktop option when you need control over codecs, bitrate, resolution, or batch processing. Put the source file in a working folder and run:

ffmpeg -i "input.3gp" -map 0:v:0 -map 0:a:0? -c:v libx264 -profile:v high -pix_fmt yuv420p -crf 20 -c:a ac3 -b:a 192k -ar 48000 -f mpegts "output.mts"

The command decodes the source, encodes video as H.264, encodes audio as 48 kHz AC-3 at 192 kbps, and writes an MPEG transport stream with an .mts filename. The question mark in -map 0:a:0? makes the audio stream optional; for a video-only source, omit that mapping and the audio options.

-crf 18 to -crf 23 is a typical H.264 quality range: lower values produce larger files and preserve more detail, while higher values reduce size. FFmpeg retains the source dimensions and frame rate unless scaling or frame-rate options are added. For an AVCHD device or editor, those source properties may still need adjustment to a supported combination.

Quality and compatibility limits

Renaming video.3gp to video.mts does not convert it and can make the file unreadable. Remuxing without re-encoding is possible only when the existing codecs and stream parameters are accepted by the target workflow. H.263 and AMR, which are common in older 3GP files, normally require transcoding to H.264 and AC-3 or LPCM.

Conversion cannot restore detail already lost through low resolution or heavy 3GP compression. H.264 MTS may improve compatibility but will not make a phone recording look like footage captured by an AVCHD camcorder.

Some AVCHD applications reject a generic MPEG-TS file unless it uses supported H.264 profiles, levels, frame rates, resolutions, and audio settings. Others require the file to be placed in the expected AVCHD folder structure. Test the converted file in the intended editor or device, and create the required folders with the application's own AVCHD import or authoring function when necessary.