VLC's XSPF still doesn't support relative paths at all despite the format itself supporting
Related to #1244 (closed), the problem with VLC simply not supporting relative paths for multimedia in XSPF lists still exists, in 2.1.5.
There's no way to read XSPF files created by other programs using relative paths with this.
For platform-independent, and program-independent, operation this is a big stopper.