Filename extensions for Motion JPEG 2000 video files are .mj2 and .mjp2, as defined in RFC 3745.
MJ2, first defined by Part 3 of the ISO Standard for JPEG 2000 ISO/IEC 15444 in November 2001[2] (ISO/IEC 15444-3:2002) as a standalone document, has later been defined by ISO/IEC 15444-3:2007, ISO/IEC 15444-3:2007/Amd 1:2010, additional profiles for archiving applications, and by ISO/IEC 15444-12 which defines the JPEG 2000 base media format, which contains the timing, structure, and media information for timed sequences of media data.
This makes MJ2 more resilient to propagation of errors over time, more scalable, and better suited to networked and point-to-point environments, with additional advantages over MPEG with respect to random frame access,[4] but at the expense of increased storage and bandwidth requirements.
[5] In contrast to the original 1992 JPEG standard, which is a discrete cosine transform (DCT) based lossy compression format for static digital images, JPEG 2000 is a discrete wavelet transform (DWT) based compression standard that could be adapted for motion imaging video compression with the Motion JPEG 2000 extension.
JPEG 2000 technology was later selected as the video coding standard for digital cinema in 2004.