What is MJPEG?
MJPEG, or Motion JPEG, is a video format that compresses each frame independently as a complete JPEG image, with no prediction between frames. The transposed spelling MPJEG is a common misspelling and does not name a separate video compression standard.
How MJPEG works
Motion JPEG compresses every frame as an individual JPEG picture, so decoding does not depend on neighboring frames. That independence makes random access and frame extraction straightforward, while repeated full images consume more bandwidth than interframe coding. The spelling MPJEG usually appears when MJPEG has been mistyped in a filename, option name, inventory record, or user interface. A media pipeline should canonicalize that label but still inspect the bitstream and container before assigning a decoder.
Key facts
- Because each MJPEG frame is independently coded, damage to one frame normally does not create the multi-frame error propagation seen with predictive codecs.
- There is no registered codec family created by transposing the letters to “MPJEG”; parsers should map that spelling only as an explicit alias for MJPEG.
- MJPEG streams occur in AVI, QuickTime, cameras, and multipart HTTP delivery, but those wrappers use different framing and metadata conventions.
When MJPEG matters
Choose MJPEG when frame-independent decoding matters more than bandwidth efficiency, as in camera capture, inspection, and frame-extraction workflows. Normalize the misspelling MPJEG in filenames, configuration, or documentation before codec lookup so valid MJPEG media is not rejected as an unknown format.