av_image_copy() expects an array of four pointers according to its
declaration; although it currently only touches pointers that
are actually in use (depending upon the pixel format) this might
change at any time (as has already happened for the linesizes
in d7bc52bf456deba0f32d9fe5c288ec441f1ebef5).
This fixes ticket #9264 as well as a warning from GCC 11.
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
(cherry picked from commit 9b17273c77ee2868ef34abc49efa70260453235b)
116dddb928