The scaling down of data is provided. At least two blocks of transformed
data samples representing at least two blocks of original data samples
are received. One of at least two tables of constants is selected wherein
each table of constants is capable of reducing the number of transformed
data samples by a different factor. The constants taken from the selected
table are applied to the at least two blocks of transformed data samples
to produce one block of transformed data samples representing one block
of final data samples. The data is processed one dimension at a time by
multiplying the data in one dimension with selected constants taken from
previously developed tables corresponding to the desired scale down
factor. Scaling down by different factors in each dimension as well as
scaling down in one dimension and scaling up in the other dimension may
be achieved. In addition, the de-quantization of the quantized transform
coefficients may be accomplished by pre-multiplication of the selected
constants when the quantization values are known. In a similar way the
re-quantization may be accomplished by a pre-division of the selected
constants. Both de-quantization and re-quantization may be combined when
the input quantized transform coefficients and output quantized transform
coefficients are desired.