lavfi/drawutils: attempt to fix subsampling.
j2k/jpeg2000: fix typo in lut_gain index

no testcase

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
jpeg2000dec: remove unneeded returns

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
j2k/jpeg2000: split stepsize in float & int variables

This is more clear and less prone to mistakes.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>