Can jwplayer play a video clip backwards in normal or slow motion speed?
No. JW Player does not have any ability to manipulate the video itself. JW Player doesn't actually "play" the video. It's just a steering script, sending the video to the browser's own native HTML5 ability, or invoking a Flash plugin if necessary. It provides its own overlays for things like controls, playlists, and advertising, but it doesn't "process" the video in any way.