If you set up in clips and archiving to delete the Alerts folder frequently to bring down your clip total and increase storage space, you then lose the thumbnail alerts for any alerts that were deleted. You still have the video, just not the thumbnail alert image.
I have found that if you manually go in and delete the images from the alerts folder and then repair/compact the DB, it will then eliminate all the image clips yet still keep the thumbnail alert images!
I emailed Ken on Tuesday inquiring about this behavior… No feedback yet.
I'd like to wait until he does before considering a work around.
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In an attempt to decipher what may be happening behind the scenes, I've been looking into this some more.
Based on the following excerpt from the help pdf, it's unclear if both the thumbnail image and the the hi-res image pointer are stored to the database (in the Alerts folder). I feel fairly confident that it must be both because -- regardless of the Trigger tab 'Add to alerts list' setting -- I can always get a thumbnail image using the
/thumbs/{filename}
HTTP interface command -- like
http://192.168.1.3:8600/thumbs/@462226516
.
I'm starting to think that when the ‘Clips and archiving’ limit functionality does its thing, it removes all alerts with hi-res pointers that no longer exist in the Alerts folder. If
Blue Iris is indeed always saving the thumbnail image to the database, It seems it could instead just replace the hi-res pointer with the thumbnail reference.
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I've also been experimenting with the JSON
clipstats
command today...
When I use it to inspect the filename (&ALERT_DB) for a alert that with a hi-res image saved via the Trigger tab 'Add to alerts list' setting, I get the following output.
If I then use Windows Explorer to search for the highlighted
[file]
in my Purple drive 'Blue Iris' folder, it locates the file in the Alerts folder (as expected).
On the other hand, here's the JSON clipstats command output for a alert that WITHOUT A HI-RES IMAGE saved via the Trigger tab 'Add to alerts list' setting.
If I use Windows Explorer to search for the highlighted
[file]
entry in my Purple drive 'Blue Iris' folder, it CANNOT LOCATE IT.
Therefore, I conclude that it is not an actual file. I think it's just an internal descriptor for the database thumbnail image.
I note also that the value for the
[filesize]
key is different.