require 3 or 4 B2A output channels

We'd been requiring 1-4 in one place and 0-4 in another,
while asserting it was 3-4 in the CLUT transform code.
This should make everyone agree on 3-4.

Add a profile with 2 output mBA tag,
which we should now fail to parse.

Bug: oss-fuzz:33281
Change-Id: Ia9db10805e4b046dc4adf112e7f8679c0e6b96c3
Reviewed-by: Brian Osman <>
Commit-Queue: Mike Klein <>
4 files changed