I've just spent a frustrating hour or so trying to create a dynamic playlist. I've done this before but had forgotten how to do this and there doesn't appear to be any guides on line (that I can find)....so I'm going to record it here for my benefit as much as anyone else's.
A auto playlist is a playlist that has a filter associated with it. For example, genre IS "Festive" will produce a list of tracks that have the genre equal to Festive. This is static and reflects the collection of tracks meeting the filter criteria at the time of the playlist creation.
A dynamic auto playlist will refilter the music library every time foobar2000 is opened. So new tracks which are ripped to the library which meet the criteria will be added to the playlist.
To create a dynamic auto playlist.....
1) Click File | Preferences. The Preferences dialog opens
2) Expand the Media Library node and select Album List. The Album List sheet is displayed
3) Click the Activate Album List WIndow / Media Library View. The Album List dialog is displayed showing the library tree with the All Music node as the root.
4) Click the All Music node.
4) Place a filter into the Filter textbox e.g. NOT Genre IS "Festive" (or all tracks except xmas stuff)
5) Right click the All Music node and click Create Autoplaylist from the context menu. A new playlist is created and added to the Playlist View.
If you now right click this newly created playlist, you'll see the option to select Autoplaylist (Album list branch - properties). This allows you to edit the filter. Everytime this playlist is selected, this filter is applied to your whole library.
Until now, I've not used autoplaylists much. However, I have used it to autofilter based on track rating. My new WDTVLive thingy (and it's rubbish library) means I'm going to have to use them a lot more, so I needed to sort this functionality out.
Anyway, I hope this is also of use/interest to others. If not, at least I'll have somewhere to look if I forget how to do it again. I must be getting old!