MP4 Converter : File extensions used on files that contain data in the *.mp4 format
mp4: official extension, for audio, video and advanced content (see above) files
.m4a: for audio-only files; can safely be renamed to *.mp4, though opinions differ on the wisdom of this.
.m4p: FairPlay protected files
.mp4v, .m4v: video-only (sometimes also used for raw mpeg-4 video streams not in the *.mp4 container format)
.3gp, .3g2: used by 3G mobile phones, may also store content not specified directly in the *.mp4 specification (H.263, AMR, TX3G).
.m4a: for audio-only files; can safely be renamed to *.mp4, though opinions differ on the wisdom of this.
.m4p: FairPlay protected files
.mp4v, .m4v: video-only (sometimes also used for raw mpeg-4 video streams not in the *.mp4 container format)
.3gp, .3g2: used by 3G mobile phones, may also store content not specified directly in the *.mp4 specification (H.263, AMR, TX3G).
O.S
