These functions currently operate on the assumption that the number
of coefficients to process is always of the form 16k+m with m<=4 or >8.
Yet this is not true when the IDCT permutation is of type FF_IDCT_PERM_LIBMPEG2
(i.e. when FF_IDCT_INT is in use).
Reviewed-by: Martin Storsjö <martin@martin.st>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
