# note: An uncompressed plane declaring the level-reduction pre-processing.
# expect: ok
# exercises: The one bit of ALPHA_PREPROCESSED_LEVELS: it makes the decoder
#   take the "decode everything in one pass" branch and keeps alpha dithering
#   alive instead of switching it off. The plane itself comes out the same as
#   with no pre-processing, so this pins the control path rather than the
#   pixels.
chunks VP8X ALPH VP8
alpha 1
alph_preprocessing 1
width 16
height 16
yac_qi 30
macroblock
coeffs y2 -20
coeffs y[2] 1:5 -3