The format phones used before smartphones
3GP was written for the era when a phone had a few megabytes to spare and a network connection measured in kilobits. It packs video and audio into the smallest workable space, which made it the standard for picture messages, early camera phones and the recording apps that shipped with them.
Files in this format still arrive from basic handsets sold today, from message archives people are finally clearing out, and from older recorders in parts of the world where cheap durable phones remained the sensible choice for far longer than they did elsewhere.
Small files, and what that costs you
The audio inside a 3GP is usually AMR, the narrowband speech codec, which means the same trade-off applies: tiny files, and only the frequency range a voice occupies preserved. Video in these clips is often heavily compressed too, though the picture makes no difference to us since we read only the sound.
For a clip of someone speaking clearly and close to the phone, this transcribes perfectly well. For a room recorded from across a table on a handset from 2009, expect gaps. It remains far quicker to correct a rough transcript than to type the whole thing from scratch while replaying the clip.
Frequently asked questions
Can you transcribe a 3GP clip that came from an old MMS?
Yes. Message clips upload the same as any other file. They tend to be short and heavily compressed, so read the result carefully, but the audio is usually intelligible enough to be useful.
My file is .3gpp or .3g2 instead. Does that matter?
No. Those are variants of the same mobile container, one of them built for a different network standard, and all of them upload and transcribe here without any conversion on your side.
Does the low video quality affect the transcript?
Not at all. We never look at the picture. Only the audio track matters, so a blocky, low-resolution clip with clear sound will transcribe better than a sharp one recorded across a noisy room.