Video file doesn't right on 4.4

I can import video,
I can encode in mpeg 4 AVI,
I have a right video timeline on GUI,
if I open the video file with other viewer works.
But the video on viewer doesn’t
works, black screen or remain still on one frame.
I had this problem some time also with 4.2 but I have resolved with a external encode with other video software.
I’m on Ubuntu 15.04.

If I convert my video file to mpg4 avi with other app now I have a message: index error: video file not suitable.

Also: with the file converted inside Ardour I can’t open the xjadeo OSD an other display option.

ok, the problem seem connected only at the file converted from Ardour, if I link eg. one .mp4 without convert it, works.