An apparatus and a method for forming a data structure that improves error resilience
when applied to the coding of hierarchical subband decomposed coefficients, e.g.,
wavelet transform coefficients. The texture unit is defined as comprising only
those AC transform coefficients that are located in one or more slices in a single
subband. The texture unit is defined as comprising only those AC transform coefficients
that are across "n" subbands, where "n" is smaller number than the total number
of "N" levels of decomposition. A texture unit can also be defined as comprising
only those bits from the DC transform coefficients that form a single bitplane.