Cannot play FLV H264 AVC file. Here is a media exception:

MediaException: MEDIA_CORRUPTED : [com.sun.media.jfxmediaimpl.platform.gstreamer.GSTMediaPlayer@1583106e] "Error media corrupted": "Error media corrupted"
at javafx.scene.media.MediaException.getMediaException(MediaException.java:139)
at javafx.scene.media.MediaPlayer$_MediaErrorListener.onError(MediaPlayer.java:2612)
at com.sun.media.jfxmediaimpl.NativeMediaPlayer$EventQueueThread.HandleErrorEvents(NativeMediaPlayer.java:718)
at com.sun.media.jfxmediaimpl.NativeMediaPlayer$EventQueueThread.run(NativeMediaPlayer.java:451)

Unfortnately, it does not go more detailed than that.

File plays normally in Adobe Flash and in VLC Video Player.