What is a Playlist?
A Playlist is actually very simple, it's nothing more than a list of audio filenames - which must already have been scanned into your Poweramp Music Library - intended to be played in a pre-defined order. Playlists are somewhat similar to the Poweramp Queue, except that Playlists are permanently available rather than just a temporary interruption.
Playlists can be either internal, which only exist within Poweramp's internal music database, or external which are read from previously created files placed within your music folders.
You can create your own new Internal Playlists within Poweramp by choosing one or more items from any Library Category view - or even the current song on the Player Screen - and using the '+Playlist' function to either create a new playlist or add to an existing one.
External playlists are read from various types of file which may have been created by another app - such as .M3U, .M3U8, .PLS or .WPL files. At their simplest, they consist of a multiple lines of text each of which defines an audio filename and the folder path where it can be found.
Important: Poweramp does not retain any musical information about Playlist entries, such as the song Title, Artist, Album, duration, etc. Once a Playlist has been created/read, Poweramp only knows how to find each song by its absolute file location in local storage - i.e. the precise directory path and filename. If you later change an audio file's name, or move it to a new folder, Poweramp will no longer be able to access the song file. In such cases, any musical information from the Library (Title/Artist/Album/etc) will be replaced by a simple placeholder of just the original raw filename. There is a 'Rescan / Resolve Playlists' option in the Playlists menu which will attempt to track down and reconnect to any such moved files (even files to which Android temporarily prevented access, which can also happen) however changed filenames can't be rediscovered.
Creating and Editing Playlists
New Playlists can be created internally within Poweramp by long-pressing on a song while browsing through the Library Categories or Search results. You can continue to select/deselect multiple items, and even create a range by long-pressing for a second time further down the list. Once you're done, tap the ‘+Playlist’ icon and either create a brand new Playlist and give it a name, or save your chosen song(s) into an existing Playlist. Note: if you choose to add content to an existing external (file-based) playlist, the updated contents will be written back to the original file.
You can even select group items from Category views - such as whole Albums, Artists, or Folders - which will include all of the songs within those items. And if you want to save the current temporary Queue into a permanent Playlist, just multi-select all of the songs within the Library=>Queue view (select a song, then tap 'All') and then tap '+Playlist'.
By default, the new songs will be added at the end of a chosen playlist, sorted using the current viewing order as defined in the Category's List Options menu. However if you long-press on the '+Playlist' icon itself, you can adjust that behaviour to insert the new content at the beginning of a Playlist, or use Shuffle to insert it in random positions. The chosen '+Playlist' mode will remain until you next change it.
You can later go back and re-order or remove songs by viewing the Playlist in the Library=>Playlists view and long-pressing on a song title. Individual songs can be moved up and down the list using the slider thumbs on the right, or you can multi-select songs and choose from other options at the bottom of the screen. The three-dots menu offers more choices, including to permanently Re-Sort the entire playlist into a new order. Again, any changes made to file-based playlists will be written back to the original file.
Exporting Internal Playlists (for backup)
As stated above, internally created playlists are saved in a local database only available to Poweramp, and are thus subject to loss if you uninstall the app or your phone dies. Playlists can be backed up as part of the overall Settings=>Export Settings/Data process, or you can export your internal playlists to permanent physical files using the Export option in the three-dots menu from the Library=>Playlists view. The playlists will be saved as .M3U8 files, by default into the Playlists folder on your device’s internal storage. You may need to first grant access permission to the folder you wish to use (particularly on recent versions of Android).
You can copy these backed-up files to another device, or use them in other apps. If you move them back into one of your current Music Folders locations, the M3U8 files will be rescanned like any other file-based playlist, which could result in the same Playlist being displayed twice.
Note: .M3U and .M3U8 files are functionally identical, and will look the same in a text editor. However M3U8 allows for a wider range of "Unicode" (UTF-8) characters to be used. M3U is really only safe for traditional 7-bit ASCII filenames - which can include upper and lower case letters A-Z and a-z, numbers 0-9, and some basic punctuation symbols. If your folders or filenames happen to include a wider range of characters - such as accented letters or international language fonts - then the more versatile M3U8 format should be used.
Advanced Discussion: Sharing Playlists from other devices
Playlist files, at their simplest, contain nothing more than a series of lines of text which provide the absolute path and filename for each included song. For example, a playlist containing a few songs located in an overall 'My Songs' folder on your Android device's SD Card might look like this:
AB12-CD34/My Songs/Artists/ABBA/Arrival/Dancing Queen.mp3
AB12-CD34/My Songs/Artists/Electric Light Orchestra/Time/Hold on Tight.mp3
AB12-CD34/My Songs/Artists/Supertramp/Breakfast in America/The Logical Song.mp3
However the same list created in a program like foobar2000 on a PC, with songs located in the default Windows Music folder, might look like this:
C:\Users\yourname\Music\Artists\ABBA\Arrival\Dancing Queen.mp3
C:\Users\yourname\Music\Artists\Electric Light Orchestra\Time\Hold on Tight.mp3
C:\Users\yourname\Music\Artists\Supertramp\Breakfast in America\The Logical Song.mp3
Clearly the two formats are not compatible: Android won't know what to do with Windows-style C:\Users\ paths, and equally Windows has no idea about Android SD Cards named AB12-CD34/. So to allow you to use a Windows-created Playlist file that has been copied to your phone, Poweramp first ignores the trivial "\" and "/" separator differences, and then uses a bit of smart searching to attempt to located each song using just the filename and the first folder that it's contained within. So in the above example, as long as Dancing Queen.mp3 is contained within a folder called Arrival anywhere in your music folders, it will be considered an acceptable match. There are a few esoteric situations where this sort of matching could become ambiguous, but it works well 99.9% of the time.
The reverse process - i.e. copying a Playlist file that was created or edited within Poweramp over to a PC - is more problematic because most PC audio players won't be able to understand the unknown path names, they expect the included drive and directory details to be fully accurate.
There is one way to make a Playlist that will work in both Android and Windows though - so you can sync a single file back and forth - which is to use relative paths. These do not include any of the incompatible device-specific information, instead using simpler paths based from the folder location of the Playlist file itself. So in foobar2000, if you saved the same M3U playlist file straight into the Music folder on your PC, it would look like this:
Artists\ABBA\Arrival\Dancing Queen.mp3
Artists\Electric Light Orchestra\Time\Hold on Tight.mp3
Artists\Supertramp\Breakfast in America\The Logical Song.mp3
If you then copied that M3U file into the My Songs folder on your Android device, Poweramp will be able to use it. And if you later add or edit song details from within Poweramp, the paths saved back into the Playlist file will remain relative - so it will still work on both machines if synced back and forth with your PC.