Testing av_video_hint_alloc()
alloc 0: OK, nb_rects=0, size>0=yes
alloc 1: OK, nb_rects=1, size>0=yes
alloc 4: OK, nb_rects=4, size>0=yes

Testing av_video_hint_get_rect()
rect 0: x=0 y=0 w=64 h=48
rect 1: x=100 y=200 w=65 h=49
rect 2: x=200 y=400 w=66 h=50

Testing type field
constant: type=0
changed: type=1

Testing av_video_hint_create_side_data()
side_data: OK, nb_rects=2
side_data rect 0: x=10 y=20

Testing OOM paths
alloc OOM: OK
side_data OOM: OK
