According to the present invention, methods and apparatus for filtering
transform coefficients are provided. Transform coefficients associated
with an input bit sequence can be zeroed to provide modified transform
coefficients associated with an output bit sequence. The transform
coefficients may represent information in a portion of data such as a
video frame, a picture, or an audio stream. In one example, the transform
coefficients are DCT coefficients of an MPEG-2 video sequence. The
transform coefficients are filtered to provide modified transform
coefficients associated with an output bit sequence. The output bit
sequence is a rescaled version of the input bit sequence.