MJ2 (Motion JPEG 2000)

Readable

video

Motion JPEG 2000 (MJ2) is a video file format known for its mathematically lossless compression, making it suitable for long-term video preservation. Standardized in 2002 as part of ISO/IEC’s JPEG 2000 (JP2) standard, MJ2 encodes timed sequences of images, with options for including audio. Unlike formats with temporal or inter-frame compression (e.g., MPEG-4), MJ2 compresses each video frame independently, enabling reversible, lossless quality. This feature makes it ideal for high-quality preservation, particularly for digitized film and analog videotape.

Identify it

Extensions	`.mj2.mjp2`
MIME types	`video/mj2`
Signatures	`0000000c6a5020200d0a870a` at byte 0 (Motion JPEG 2000)
PRONOM	`fmt/337`
Wikidata	`Q3273017`
Library of Congress	`fdd000127`

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Open it

ImageMagickOpen sourcereads and writes · ImageMagick License
OpenJPEGOpen sourcewrites · 2-clause BSD License
FFmpegOpen sourcereads · LGPL-2.1-or-later / GPL-2.0-or-later
ConverseenOpen sourcereads · GNU General Public License, version 3.0
ExifToolOpen sourcereads · Artistic License / GNU General Public License, version 1.0 or later
nomacsOpen sourcereads · GNU General Public License, version 3.0
OpenImageIOOpen sourcereads · BSD licenses
Adobe Photoshop Elements 3.0reads and writes
Grokreads and writes
IrfanViewreads and writes · freeware
PaintShop Pro X4reads and writes
Q1936840writes
Q650922writes · freeware / proprietary license
ENVIreads · proprietary license
ACDSeereads · proprietary license
Advanced Guard for Information Securityreads
Affinity Photoreads
ArcGISreads · proprietary license
Pinnacle Studio 17 Ultimatereads
Quick Lookreads

Convert it

To	With	Fidelity	Command and losses
Portable Network Graphics	ImageMagick	Lossless	`convert in.j2c out.png` Pixels kept; some metadata, colour profiles or layers may be dropped.
Tagged Image File Format	ImageMagick	Lossless	`convert in.j2c out.tif` Pixels kept; some metadata, colour profiles or layers may be dropped.
FLAC (Free Lossless Audio Codec) 1.2.1	FFmpeg	Partial	`ffmpeg -i in.mj2 out.flac` Audio track only: the video is dropped.
Waveform Audio	FFmpeg	Partial	`ffmpeg -i in.mj2 out.wav` Audio track only: the video is dropped.
GIF 89a	ImageMagick	Lossy	`convert in.j2c out.gif` Reduced to 256 colours.
JPEG File Interchange Format 1.02	ImageMagick	Lossy	`convert in.j2c out.jpg` Lossy compression.
Matroska 1-4	FFmpeg	Lossy	`ffmpeg -i in.mj2 out.mkv` Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.
MPEG 1/2 Audio Layer 3	FFmpeg	Lossy	`ffmpeg -i in.mj2 out.mp3` Lossy audio only: the video is dropped.
MPEG-4 Part 14	FFmpeg	Lossy	`ffmpeg -i in.mj2 out.mp4` Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.
Ogg	FFmpeg	Lossy	`ffmpeg -i in.mj2 out.ogg` Lossy audio only: the video is dropped.
WebM	FFmpeg	Lossy	`ffmpeg -i in.mj2 out.webm` Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.
WebP	ImageMagick	Lossy	`convert in.j2c out.webp` Lossy compression.

Sources

From Converters (FFmpeg, ImageMagick, Pandoc, LibreOffice), Just Solve the File Format Problem (File Formats Wiki), PRONOM, Wikidata. Updated 2026-10-24.

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