This is the primary reason that custom DCTs and a whole slew of predefined DCTs are included in the standard. The common 8x8 default works in most cases, but yo

This is the primary reason that custom DCTs and a whole slew of predefined DCTs are included in the standard. The common 8x8 default works in most cases, but you can optimize heavily for edge case images (in which case, baking in the DCT is made up for by the decreased data size).