Question about "Video preview thumbnail extraction" scheduled task.

[Gilgamesh_48 1240]

I have just a few movies and a few shows that do not have bif files. However when I manually run the "extraction" scheduled task they do not get created. If I remove the movie from my library and scan the library then add the movie back in and rescan again the bif file gets created. That is it seems that the bif file creation only happens when a new movie is detected and that means that if I have a corrupted bif file the only way I can get it recreated is to remove the movie form the library and rescan the library and then add it back in an rescan again.

Should not the task "Video preview thumbnail extraction" scan the database a create bif files for the movies that do not currently have one? If it is supposed to do that then it is not so I guess this becomes a bug report. It really seems that "Video preview thumbnail extraction" does not actually do anything except if it gets called for a movie when it is first detected.

Is there any way that actually works other than the remove and recreate that will create a bif file if one is deleted? I do not like having to remove a movie just to get the bif file recreated.

[Luke 42077]

Hi, it might have failed for those files in the past. It will not keep trying again and again. If you refresh the metadata on those videos then it will try again next time.

[mchahn 22]

A somewhat related question.  In my Scheduled Tasks page there isn't anything like "Video preview thumbnail extraction'.  Do I have to do something to install that?  I'm on Version 4.8.0.47 beta.

[Luke 42077]

6 minutes ago, mchahn said:

A somewhat related question.  In my Scheduled Tasks page there isn't anything like "Video preview thumbnail extraction'.  Do I have to do something to install that?  I'm on Version 4.8.0.47 beta.

Do you have the feature enabled on at least one library?

[mchahn 22]

Yes.  Long story ...

I am in the process of moving to a new server.  I installed on the new and it worked great.  I had one series folder moved over and previews worked great.  On the old server i never enabled previews.

Then I replaced my new /var/lib/emby folder with the old one.  That worked great and everything came over.  I  copied over a second series folder and the scan picked it up fine.  I then enabled previews in the settings.  The second folder has no bif files which is to be expected.  So I think I just need to run some task. But there is no task to run.

[mchahn 22]

I just copied a third folder over hoping that would automatically generate the bifs but it didn't.  It is as if the lack of setting in the old var/lib/emby is stuck and turning it on the the new server doesn't actually turn it on.

[Luke 42077]

Hi, actually this scheduled task doesn't have any conditions that would cause to be hidden? Are you sure you scrolled down through the list of scheduled tasks?

[mchahn 22]

[mchahn 22]

Don't forget this is a pretty old version.

[Luke 42077]

9 hours ago, mchahn said:

Don't forget this is a pretty old version.

I think in your version it is called thumbnail image extraction if memory serves correctly.

[mchahn 22]

Thumbnail image extraction takes zero seconds.  It haven't seen bifs since that first series folder in the clean install. I was excited to see it work then.

Do you think it would be worth trying to start clean again and then only copy the users db over instead of all /var/lib/emby?  The watch history is extremely important.  The old and new servers are the identical version so I would think the dbs would match.  But no if there is some inter-dependence with the library db it might not work.

[mchahn 22]

I did a clean install and copied users.db over before running it. When it started ffmpeg churned for a minute or so and the old folders got bifs (yay!).

I copied over a new series folder with one mkv file.  Nothing automatically happened.  Then I ran the task "Thumbnail image extraction" which ran for 20 secs which was encouraging, but I can't find anything new in the data.  No bifs are in the new folder. Surely the task was doing something for those 20 secs.

I am confident the task "Thumbnail image extraction" is the answer to my original question.  Now I just need to figure out what it is doing and why it doesn't create bifs.

Any ideas?

[mchahn 22]

In case anyone cares, I did a new install of the same version emby, on a new server, with same media drives, and now preview bifs work great on old and new series folders.  Oh well ...

[Luke 42077]

On 8/4/2025 at 6:19 PM, mchahn said:

In case anyone cares, I did a new install of the same version emby, on a new server, with same media drives, and now preview bifs work great on old and new series folders.  Oh well ...

Hi, that's interesting. Thanks for following up.