Free online 3GP to M2T converter

What the 3GP format is

3GP is a multimedia container defined for older 3G mobile networks and phones. It commonly contains H.263, MPEG-4 Part 2, or H.264 video with AMR-NB, AAC, or AMR-WB audio. Older phones, mobile video recorders, and some low-bandwidth messaging systems create 3GP files; media players and editors may identify them as .3gp or .3g2.

What the M2T format is

M2T usually denotes an MPEG-2 transport stream stored with an .m2t extension. HDV camcorders and compatible capture applications commonly use it for MPEG-2 video with MPEG-1 Layer II audio. Transport streams support packetized audio and video and are suited to camera recording, capture, and some broadcast-oriented workflows, but many general video editors accept .mts, .m2ts, or .ts more readily than .m2t.

The extension alone does not guarantee an HDV-compliant stream. A receiving application may require a specific frame size, frame rate, bitrate, audio format, and interlacing mode.

How to convert 3GP to M2T

For a browser-based conversion without installing software, use the free converter on 101convert.com: select the 3GP file, choose M2T as the output format, start the conversion, and download the resulting file. Check the destination program's M2T requirements before relying on the default settings.

FFmpeg provides control over the codecs and stream parameters. A general MPEG-2 transport-stream conversion is:

ffmpeg -i input.3gp -c:v mpeg2video -q:v 2 -c:a mp2 -b:a 192k -ar 48000 -f mpegts output.m2t

-c:v mpeg2video transcodes the source video to MPEG-2, while -c:a mp2 converts the audio to MPEG-1 Layer II. The -q:v 2 setting uses high variable quality; use a bitrate option instead when the target application specifies one.

For an HDV-style 1440×1080, 25 Mbps stream at 25 interlaced frames per second, use parameters that match the source standard:

ffmpeg -i input.3gp -vf "scale=1440:1080:flags=lanczos,setsar=4/3,format=yuv420p" -r 25 -c:v mpeg2video -b:v 25M -minrate 25M -maxrate 25M -bufsize 17825792 -flags +ildct+ilme -top 1 -c:a mp2 -b:a 384k -ar 48000 -f mpegts output.m2t

Change -r 25, -top 1, the frame size, and the sample aspect ratio when the required HDV standard uses a different frame rate, field order, or display shape. Do not use this preset merely because the filename ends in .m2t; a generic MPEG-2 transport stream may need different settings.

In a graphical FFmpeg front end, import the file through Open, select MPEG-2 video, MPEG audio, and MPEG transport stream as the output container, set the required frame size and bitrate, then save with an .m2t extension.

Quality and compatibility limitations

This is normally a lossy transcode: 3GP video is decoded and encoded again as MPEG-2, so quality can decrease and the output can be much larger. Upscaling a small phone recording to 1440×1080 adds pixels but not recovered detail.

Conversion can also change frame rate, field structure, aspect ratio, and audio timing. Inspect the source with ffprobe input.3gp and preserve its frame rate when possible. If the target software rejects the file, verify that it expects MPEG-2 transport stream rather than MPEG-2 program stream, and check its required resolution, interlacing, bitrate, audio codec, and extension.