Transform coefficients for blocks of pixels in an original picture are
quantized to produce respective sets of quantization indices for the blocks of
pixels. The quantization indices for at least some of the blocks are produced by
using a quantization step size that is not uniform within each block. Largest magnitude
quantization indices are selected from the respective sets of quantization indices
for (run, level) encoding to produce the (run, level) encoded picture. For example,
MPEG-2 coded video includes a set of non-zero AC discrete cosine transform (DCT)
coefficients for 88 blocks of pixels. For scaling the MPEG-2 coded video,
non-zero AC DCT coefficients are removed from the MPEG-2 coded video to produce
reduced-quality MPEG-2 coded video that includes no more than a selected number
of largest magnitude quantization indices for the non-zero AC DCT coefficients
for each 88 block.