the input image alignment is not PADDED.
*/
DCPOMATIC_ASSERT (alignment() == Alignment::PADDED);
+ DCPOMATIC_ASSERT(size().width > 0);
+ DCPOMATIC_ASSERT(size().height > 0);
+ DCPOMATIC_ASSERT(out_size.width > 0);
+ DCPOMATIC_ASSERT(out_size.height > 0);
auto scaled = make_shared<Image>(out_format, out_size, out_alignment);
auto scale_context = sws_getContext (