I can convert JPG and PNG images to BPG (Better Portable Graphics) animation, using the following command:
bpgenc -a input_%03d.jpg -o out.bpg
According to the BPG documentation it is not possible to use BPG images for conversion to BPG animation.
- Animations: with the '-a' option, animations can be encoded from a sequence of PNG or JPEG images, indexed from 1 or 0.
I can't find an explanation for why this is the case.