Use the commands below to test: (href: https://trac.ffmpeg.org/wiki/Blend)

I. make an image for test
ffmpeg -f lavfi -i color=s=256x256,geq=r='H-1-Y':g='H-1-Y':b='H-1-Y' -frames 1 \
-y -pix_fmt yuv420p test.jpg

II. blend in sw
ffmpeg -i test.jpg -vf "split[a][b];[b]transpose[b];[a][b]blend=all_mode=multiply,\
pseudocolor=preset=turbo" -y multiply_sw.jpg

III. blend in vulkan
ffmpeg -init_hw_device vulkan -i test.jpg -vf "split[a][b];[b]transpose[b];\
[a]hwupload[a];[b]hwupload[b];[a][b]blend_vulkan=all_mode=multiply,hwdownload,\
format=yuv420p,pseudocolor=preset=turbo" -y multiply_vulkan.jpg
Signed-off-by: Wu Jianhua <jianhua.wu@intel.com>