| m00 | Magic Lantern RAW Video |
| m01 | Magic Lantern RAW Video |
| m02 | Magic Lantern RAW Video |
| m03 | Magic Lantern RAW Video |
| m04 | Magic Lantern RAW Video |
| m05 | Magic Lantern RAW Video |
| m1pg | Media 100 iFinish Video Clip |
| m1v | Mpeg Video |
| m2p | Mpeg-2 Program Stream |
| m2ps | Mpeg-2 Program Stream |
| m2t | MPEG-2 Transport Stream |
| m2t | Sony AVCHD Video |
| m2ts | Sony AVCHD Video |
| m2v | Mpeg Video |
| m4f | Sony Network Camera MPEG-4 Video |
| m4u | M4U Playlist File |
| m4v | iTunes M4V Video |
| m65 | REI Camera System Video |
| map | HD DVD Advanced Content Time Map |
| matroska | Matroska Video |
| mbr | Zune Smooth Streaming File |
| mcam | MediaCam Video |
| mcc | MacCaption Closed Caption File |
| mcmovie | MadCap Mimic Movie |
| mcmv | MadCap Mimic Movie |
| mj2 | Motion JPEG 2000 Video |
| mjp | MJPEG Video |
| mjp2 | Motion JPEG 2000 Video |
| mjpeg | MJPEG Video |
| mjpg | MJPEG Video |
| mk3d | Matroska Stereoscopic/3D Video |
| mks | Matroska Subtitle |
| mkv | Matroska Video |
| mkv3d | Matroska Stereoscopic/3D Video |
| mlv | Magic Lantern RAW Video |