This allows for correct output when using muxers (like the MOV/MP4 muxer)
that require frame_size set.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
(cherry picked from commit 077f47ff59b9e5e1a523d924a0307105dcdee4bc)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>