What Does Emby Server Reference To Determine If an Existing File Gets Scanned During the Scheduled Task?

[DayOfTheJackal 0]

Hello everyone,

I recently migrated my Emby Server along with all my media files. They’re exact copies in terms of data and folder structure, but the process of accessing them changed their original date attributes (e.g., creation/modification timestamps).

After the migration, each time I run the “Scan media library” scheduled task, Emby seems to re-scan these files from scratch, causing a noticeable slowdown. My suspicion is that Emby sees the changed timestamps as if the files were new or modified, even though the filenames, paths, and sizes are the same.

Here’s what I’ve tried so far:

• Checked the 'MediaItems' table in Emby’s database and noted the DateModified column.
• Synced the 'DateModified' value with the file system “Modify” timestamp (from the stat command) by converting it to epoch and updating Emby’s database to match exactly.
• Even after ensuring the database’s DateModified matches the file system timestamps, Emby still re-scans those files.

It looks like there may be something else that Emby references when determining whether a file needs re-scanning—something beyond the filename, path, size, and DateModified attributes. I might be missing an additional step.

Has anyone experienced this before, or have any insights into which factors Emby checks during scans? Any advice on preventing repeated scans for these unchanged files would be greatly appreciated!

Thank you!

[Luke 42077]

Hi, date modified timestamps. The automatic refresh interval is another. Changes to nfo files, images added or removed.

[DayOfTheJackal 0]

5 minutes ago, Luke said:

Hi, date modified timestamps. The automatic refresh interval is another. Changes to nfo files, images added or removed.

Thanks for the reply, @Luke!
 

I just want to confirm a couple of points to ensure I fully understand how Emby handles these scans:

• Timestamp Matching

  Am I correct in thinking that if the Modify timestamp from stat (converted to epoch) matches the DateModified in Emby’s database, the server should recognize the file as unchanged and skip re-scanning it?

• NFOs & Automatic Refresh

  I’ve disabled NFO files and set the Automatic Refresh Interval to “Never,” so that shouldn’t be a factor.

• Images Affecting Scans

  You mentioned images. Would any change in images—such as adding or removing an image file, or having a different timestamp—lead to Emby re-scanning the corresponding video files in that directory?
  Specifically, if an image change is detected in a folder, do all video files in that folder then get rescanned, regardless of their matching timestamps?

Thank you again for the guidance!

[Luke 42077]

Hi,  yes you are correct.

 As far as the third one goes, I would say ideally no but I would bet that sometimes probably it does happen.

we’re dealing with hypotheticals so it’s best to look at a specific example.

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