MP4 is a multimedia container format defined by MPEG-4 Part 14 (ISO/IEC 14496-14). It is based on the Apple QuickTime format, but is not identical to it.
It is a successor to the older MOV format, and is used for video (with H.264 and H.265 codecs) and audio (with AAC and AC-3 codecs).
It is used by iTunes for music and video downloads, and by many other services for video streaming. It is also used for video files on Blu-ray discs.
File types
.3g2.3ga.3gp.3gp2.3gpa.3gpp.3gpp2.m4a.m4b.m4p.m4r.m4v.mp4.mp4v
Also appears as
audio/m4aDeprecatedaudio/mpeg4-genericDeprecatedaudio/x-m4aDeprecated