# note: A compression method of 2, past the lossless one.
# expect: reject
# roundtrip: no
# exercises: The header byte packs four fields into two bits each, and only
#   the method and the pre-processing have values the format does not define.
#   This is the first of them.
chunks VP8X ALPH VP8
alpha 1
alph_compression 2
width 16
height 16
yac_qi 30
macroblock
coeffs y2 -20
coeffs y[2] 1:5 -3