Sidecar metadata
A metadata sidecar stores associated information outside the media resource, relying on a defined association and schema rather than being part of the image or media payload.
A sidecar stores related information beside a resource rather than inside it. For example, a raw-photo workflow can use an XMP file associated with the camera file:
Capture-0042.raw
Capture-0042.xmp
These are invented names illustrating association. The reader's supported naming and lookup rules decide how it connects them.
Association and schema solve different problems
| Requirement | Question |
|---|---|
| Association | Which media resource or entity does this file describe? |
| Syntax/schema | How are fields represented and what do they mean? |
| Version relationship | Does the record still describe the current resource? |
| Merge policy | How does it interact with other metadata candidates? |
A syntactically valid sidecar can still be attached to the wrong copy. Sharing a basename can be useful evidence within a naming convention, but it is not a universal content fingerprint.
The format also determines whether the record contains descriptions, applicable edit instructions or other information. A sidecar's existence does not make every field meaningful to every media library.
For Emby, supported local metadata is an input to the applicable library reader. Metadata Manager describes editing and refresh behavior; it does not imply that every external XMP property or every sidecar convention is imported. The useful comparison keeps source association, supported field mapping and the displayed record separate.
External storage permits a different editing boundary
Writing a sidecar can leave the media payload unchanged. That is useful when a workflow wants to retain a master while recording additional description or supported processing instructions.
The output appearance changes only when an application actually reads and applies those instructions. A player ignoring a raw-development recipe can show a prepared preview instead.
Conversely, a database-only title edit is not automatically an update to the sidecar. There are separate read, merge and write-back operations.
Moves and duplicates need a coherent relationship
Moving a media file without its sidecar can lose the external context. Replacing the media while keeping an old sidecar can preserve a relationship to the wrong source version.
A duplicate basename in another folder introduces another association context. Copying just the metadata into that folder should not be assumed to transfer correct capture or identity information to unrelated media.