Format guide
How Android Motion Photos store movement
A supported Motion Photo combines a JPEG still, XMP metadata and an MP4 motion clip. PhotoReady reads those bytes locally and keeps the original parts available for download.
Container structure
Current Android Motion Photo metadata can describe a primary JPEG item and a secondary video item whose length locates the MP4 at the end of the file. Older Google files may use a MicroVideoOffset value instead.
Why motion disappears
Messaging, social and image-editing apps often re-encode only the JPEG portion. A screenshot also contains no appended video. When metadata is missing but an MP4 remains, PhotoReady reports that it found the clip by scanning instead of pretending metadata was intact.
Compatibility language
Structural validation confirms that a file can be parsed by PhotoReady. Gallery recognition is device- and version-specific and remains a separate device acceptance gate.