Not from decomp

* The explosive effect when the firework's charge detonates * resulting in a small variety of amusing colours. * D_802874BE appears to be zero. */

Not from decomp

* Allegedly controls fireworks movement. */

* Navigation of the main splash start screen menu * Also handles debug menu options */

build a table that decodes both magnitude and value of small ACs in one go.

decode image to YCbCr format

@OPTIMIZE: store non-zigzagged during the decode passes, and only de-zigzag when dequantizing

returns 1 if "a*b + add" has no negative terms/factors and doesn't overflow

after we see SOS