test1: def filter repeat .
test1: compression.
direction=compress id=40000 cd_nelmts=2 cd_values= 0 18
test1: decompression.
filter(40000): |params|=2 params= 0 18
direction=decompress id=40000 cd_nelmts=2 cd_values= 0 18
data comparison: |array|=256
no data errors