DVD Media Quesion

Do all DVD players that support DVDR’s also support DVDR DL(DVD9)? Reason in asking this is it seems that some movies that I have that are burned on DVD9s play fine on neighbours player but some others that don’t play.

The same applys for certain Brands as well as Formats and DVD-5 vs DVD-9 some work some dont. Some Stanalone DVD Players are fussier than others. Bitsetting to DVD-ROM when possible can solve some compatibility problems.