Abstract: Efficient decoding of an hierarchical, variable length, encoded data sequence containing embedded uncoded data into a sequence of fixed length instructions for subsequent processing by a digital video processor or the like is realized in an apparatus including a decoder having a plurality of variable length code decoding elements and a control structure embedded within each decoding element for transferring the decoding operation to an appropriate one of the decoding elements in response to a prior output from the decoder element. As the encoded data sequence is processed by the apparatus, a predetermined length of the sequence is stored in a register. The control structure further responds to the encoded data sequence to initiate selection of either the predetermined length of the sequence stored in the register or a portion of the decoder output as the fixed length instruction to be output by the apparatus.

Abstract: A system for reducing image data redundancies through progressive sub-band coding. The image is separated into a selected plurality of sub-bands, and the sub-band with the largest non-redundant data content is chosen and used to predict the data in the other sub-bands. Only prediction error information of the predicted sub-bands encoded and transmitted together with the encoded chosen sub-band. An overall performance error signal can also be evaluated at the encoder's end and used to further improve performance. The sub-band encoding can be performed recursively to still further reduce the encoded data.