Prior to this, the results were not saturated into the uchar/ushort range before
being written. The characteristics of the Lanczos filter exposed this issue.
In addition, the results were truncated rather than rounded, which resulted
in checkerboard artifacts in solid color areas and were noticeable when
using Lanczos with 8-bit input.
Example:
ffmpeg -init_hw_device cuda -f lavfi -i testsrc2=s=960x540,format=yuv420p \
-vf hwupload,scale_cuda=format=yuv420p:w=-2:h=720:interp_algo=lanczos \
-c:v h264_nvenc -qp:v 20 -t 1 <OUTPUT>
Fix#20784
Signed-off-by: nyanmisaka <nst799610810@gmail.com>
There are lots of files that don't need it: The number of object
files that actually need it went down from 2011 to 884 here.
Keep it for external users in order to not cause breakages.
Also improve the other headers a bit while just at it.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
