# note: A frame whose alpha chunk comes after its image.
# expect: reject
# anim: reject
# info: reject
# exercises: Both chunks are stored -- StoreFrame() has no opinion on their
#   order -- and it is IsValidExtendedFormat() that compares the two offsets
#   afterwards and requires the alpha to precede the image. The still-image
#   form of the same mistake is alph-after-image, which libwebp's own
#   decoder accepts, so the two layers do not agree about it.
alpha 1
frame
frame_duration 100
chunks VP8 ALPH
alph_raw
width 16
height 16
yac_qi 30
macroblock
coeffs y2 -20