.MP21 File Extension

Media storage format developed by the Moving Picture Experts Group (MPEG); based on a "meta-box" format that contains audio or video data referred to as the "Digital Item;" also includes metadata that describes the media.

MPEG-21 files typically use the .M21 file extension.

Media file saved in the AXMEDIS content distribution format; may contain multiple types of media, such as images, video, and audio data; may also include metadata, and DRM copy-protection information.

MP21 files are similar to .AXM files, but they used a more compressed format and can be opened more quickly. MP21 files can be created with AXMEDIS Editor and opened with AXMEDIS Player.