I turned on “Detect Commercials and mark for skip” in the DVR Settings
Then I went Settings>Mange>Libraries>Edit Library >Advanced> Turned on AD Detection for all items.
Even before making those changes I was able to Detect Commercials
After turning on the ad detection, it has to be actually performed. That doesn’t happen during playback. It happens overnight, during the server maintenance. And it can stretch over more than one night if there are many items to process and/or the server machine is rather slow. https://support.plex.tv/articles/201553286-scheduled-tasks/
Those look like chapters in the video, which Plex doesn’t generate, and aren’t used to skip ads. You can use Get Info > View XML to see if the are any ad <Marker>s that Plex has generated.
I thought it just added <Marker>s to the database, or at least, only considered markers for skipping content, not chapters. OP’s XML file indicates that there are chapters titled “Advertisement”, but only intro/credits markers. I would have expected something like this if Plex had generated ad markers for the file:
Maybe I’m mistaken, but as far as I can tell from that XML, Plex doesn’t know there are ads in that file. I don’t have many items in my library with commercials, but with the handful that I do have, Plex didn’t create any chapter markers, only commercial markers in Plex’s database. Does manually analyzing the episode/season/show kick off anything?
I’m saying that even if they are generated by Plex, I don’t believe Plex uses chapters to determine when to show the ‘Skip Ads’ button, only commercial markers.
Plex would need to recognize the ads by itself.
I don’t know how far it got analyzing your library for ads. If you just enabled the setting, it is totally possible that it simply didn’t get to this particular file yet.