Excuse my ignorance, but is it possible to configure m3u file to either play in strict order or to shuffle? I have a lot of classical music (strict order of movements) and of light music (shuffle preferred).
In general, playlists are plain text files and the text in those files is fixed.
AFAIK there is no attribute that tells a player to switch the replay mode.
In Mp3tag you could load a playlist, apply the function View>Sort by>Random to shuffle the loaded files and the resave the playlist.
If that is not what you are after, you would have to rely on the features of your player to modify the otherwise fixed order represented in the playlists.
Thanks. That's what I feared.