The playlist lists the file names (absolute or relative path) or URLs to play.
There are only two directives in a playlist:
1. The header and first line of the file.
#EXTM3U
2. The tracks.
#EXTINF:length,Artist Name - Track Title
where
Any format (mp3, ogg, …) which can be decoded by the player will be valid.
Example:
#EXTM3U #EXTINF:133,song1 ./some directory/song1.mp3 #EXTINF:256,some band - song2 ./some other directory/song2.mp3