displaydescription not working
By default, JW Player will display your video's description below its title. If you have set a description, but don't want it to display here, set this option to false. Note: Setting both displaytitle and displaydescription to false will remove the gradient that appears behind the title/description.
I find that this is not working by default. I see title but no description.
Have not investigated variances , but I am using xml playlists. These descriptions were working fine in JW6