# note: A compressed alpha plane of three values, through a palette.
# expect: ok
# exercises: The shape that reaches DecodeAlphaData(): one transform, that
#   transform colour-indexing, no colour cache, and the red, blue and alpha
#   codes each a single symbol. Written rather than pasted from an encoder,
#   so the neighbouring cases can each break one of those four conditions
#   and watch the decoder fall back. Three values in a two-bit index, so a
#   packed byte holds four pixels and the fourth index is the unused one.
chunks VP8X ALPH VP8
alpha 1
width 16
height 16
yac_qi 30
macroblock
coeffs y2 -20
alph_plane
transforms color_indexing
palette_colors 0x00000000 0x0000c800 0x0000ff00
pixels 0x24 x64