audio/3gpp

The sound of pre-smartphone voice memos: audio-only .3gp files from the container 3GPP standardized for mobile networks (TS 26.244), carrying AMR or AAC streams recorded by feature phones and early Android devices. RFC 3839 registered the pair of 3GPP types in 2004 and is candid about the split: audio/3gpp is for files with no video or timed text, but an audio-only file may also legitimately travel as video/3gpp, so consumers should accept either. The container is ISO base media format, so the identifying ftyp box with a 3gp brand sits at offset 4 — the same structure as MP4, which this site's sniffer already attributes to video/mp4.

Defined by RFC 3839 · IANA registration. Registry facts from the IANA media-types registry via mime-db.