In FCPX I burned a DVD and included CEA-608 captions, per Apple's instructions. The captions displayed fine in Mojave's DVD Player when Closed Captions are enabled in the Features menu. But when I played the disk in a Sony Blu-ray DVD player, pressing the Subtitle button on the player's remote resulted in the text from my Chapter Markers to display instead of the subtitles. I got the same result using another Sony BR DVD player.
My video has SRT captions, too. They worked fine when exported and uploaded to YouTube separately, but they're not listed in the "Include captions" drop-down menu in the Share to DVD Settings menu, so I presume they're not intended for DVD use.
What "caption" format is compatible with a typical DVD player's Subtitle function?