Noticed that frame sizes multiple of 512 are a little faster to write (credits:
CHDK and confirmed with my benchmark; also DMA block size is 512, so it makes sense). So, I've rounded things to 64x32 or 128x16, to make sure frame size is multiple of 512.
And indeed, according to my benchmark, 1920x1088 is a little faster to save than 1920x1080.
Now it's your job to calm down the guys who will flood the forum asking where did 1920x1080 disappear
