problem streaming f4v files with jwplayer

I want to stream f4v files with jwplayer. While playing flv files works great with f4v I've got the problem that the video plays only when the complete file is downloaded (resulting in bad user xp).

Is this is expected behaviour o开发者_StackOverflow中文版f jwplayer for f4v files? May this be a result of the used encoding?

Seems like there's an answer here:

Playback of F4V using FLVPlayback won't use progressive download

Didn't try it yet though.