[meta-freescale] imx53: SDL2 +directfb video render Problem

[Development - KBlue]

Hello,
I'm trying to render a video stream from a SIP call (pjproject) using SDL2
and directfb on iMx53.
When the display is horizontally oriented (l = 800; h = 480),  just before
the correct video stream, a black rectangle is drown, but it disappears
after at least 1 second.
The problem is that unfortunately my application has to be rotated, and
rotating 270° the display of directfb (l = 480; h = 800) the black rectangle
doesn't disappear.

Anyone has experienced this kind of problem?
Thanks in advance,

Kind regards,
Riccardo.