1. Understand what “duplicate” means
Byte-identical files contain exactly the same file data. A renamed copy can still be byte-identical, while a re-encoded export usually is not. A visual duplicate means that the complete picture content matches, even when file data differs.
A short excerpt inside a longer video is a section match, not a duplicate of the whole file. Two videos sharing an opening or one scene also need to be distinguished from full-content matches. MediaDNA Library separates these results so you can review the right kind of relationship.
2. Prepare the folders you want to compare
Connect the relevant local drives, external disks or mounted NAS folders. Add those folders to MediaDNA Library and wait for indexing to finish. The originals stay in their existing locations; indexing does not create a backup.
Check indexing progress and read problems in Activity, then check file locations and availability in All Files. Include both folders if you want to compare a working collection with a backup. Missing or unindexed footage cannot be treated as covered by the check.
3. Review full-content matches in the library
Open Duplicate Files after indexing. Review each group, inspect the previews and compare file locations and availability. Different names, file sizes or resolutions do not by themselves tell you whether complete visual content matches.
For a practice run, use a small folder of your own footage and a copy stored under a different name. Index both locations, then inspect any resulting group and confirm the paths. If you also try a re-encoded export or a short excerpt, inspect the actual result instead of assuming all three belong to one duplicate group.
4. Check a new file before adding it
Select the new video in Content Search before adding its folder to the library. The query file is used for the search and is not automatically indexed. Review verified full-content matches to see where existing copies are stored.
If you want to locate a short excerpt inside a longer recording, continue with section search and inspect the returned time range. A section result can help you recover footage, but it does not justify removing either whole video as a duplicate.
5. Choose which versions to keep
Inspect the picture quality and the audio and subtitle tracks you need. Also consider the file location, whether it is accessible, and whether the second copy is an intentional backup. A complete visual match does not choose the best version for you.
You may keep every copy. Removal is optional and requires your selection and confirmation. Local removal normally uses the system trash; network files may require permanent deletion. Read the confirmation and keep a separate backup before removing material you may need.
6. When an expected match is missing
First check library coverage: are the folders included, are the drives connected, and did indexing finish without read errors? A file outside the indexed library cannot appear simply because another copy exists somewhere in your storage.
Extensive cropping, overlays or edits can make matching harder. A shared excerpt should be checked with section search rather than treated as a complete duplicate. No match does not establish that a video is unique, original or free to reuse.