Nova Patents
EP0875859B1

Method and apparatus for decoding data

Abstract

This record has no abstract on file.

EP0875859B1, drawing sheet 1
Sheet 1 of 183

Term

Term ended

Expired 29 April 2018, 8.4 years ago.

  1. Priority
  2. Filed
  3. Granted
  4. Expired
  5. Today

13 claims: 5 independent, 8 dependent

  1. 1
    An apparatus for decoding a stream of data (Fig. 82) comprising a plurality of variable-length code words, a plurality of not-encoded bit fields of variable-length, and a plurality of not-encoded bit fields of fixed length, wherein the variable-length code words are interleaved with the not-encoded bit fields of variable length and the not-encoded bit fields of fixed length, the apparatus comprising:preprocessing means (1171) for removing the plurality of not-encoded bit fields of fixed length from the stream of data and outputting the variable-length code words interleaved with the not-encoded bit fields of variable length as output blocks of data to be decoded;and decoding means (1184) for decoding the variable-length code words in the blocks of data to be decoded and outputting decoded data to an output means (1188) of the apparatus;characterised in that : the preprocessing means (1171) is operable to generate and output signals indicating the positions within the output blocks of data of the removed not-encoded bit fields of fixed length;and the apparatus further comprises: means (1185,1182,1231,1234,1172,1180) arranged to use the signals indicating the positions of the removed not-encoded bit fields of fixed length for detecting and removing the not-encoded variable-length bit fields from the blocks of data to be decoded;and means (1173,1181,1183) for passing the signals indicating the positions to the output means (1188) of the apparatus in synchronisation with the data being decoded such that, if there is a multiplicity of the variable-length code words between the not-encoded bit fields of fixed length in the input data stream, then a multiplicity of corresponding decoded data is generated at the output means (1188) of the apparatus between signals indicating positions corresponding to the not-encoded bit fields of fixed length in the input data stream.
  2. 6
    A method of decoding a stream of data (Fig. 82) comprising a plurality of variable-length code words, a plurality of not-encoded bit fields of variable-length, and a plurality of not-encoded bit fields of fixed length, wherein the variable-length code words are interleaved with the not-encoded bit fields of variable length and the not-encoded bit fields of fixed length, the method comprising:a preprocess of removing the plurality of not-encoded bit fields of fixed length from the stream of data and outputting the variable-length code words interleaved with the not-encoded bit fields of variable length as output blocks of data to be decoded;and a decoding process of decoding the variable-length code words in the blocks of data to be decoded and outputting decoded data to an output;characterised in that : the preprocess generates and outputs signals indicating the positions within the output blocks of data of the removed not-encoded bit fields of fixed length;and the method further comprises: using the signals indicating the positions of the removed not-encoded bit fields of fixed length to detect and remove the not-encoded variable-length bit fields from the blocks of data to be decoded;and passing the signals indicating the positions to the output in synchronisation with the data being decoded such that, if there is a multiplicity of the variable-length code words between the not-encoded bit fields of fixed length in the input data stream, then a multiplicity of corresponding decoded data is generated at the output between signals indicating positions corresponding to the not-encoded bit fields of fixed length in the input data stream.
  3. 9
    The method according to any of claims 6 to 8, wherein the preprocess outputs the plurality of variable length code words interleaved with the not-encoded bit fields of variable length as words of fixed length composed of bit fields of fixed lengths such that an outputted single bit field has a corresponding tag indicating whether the outputted field is passed or removed by the preprocess, or passed by the preprocess and following or preceding a marker that is a not-encoded bit field of fixed length.
  4. 10
    The method according to any of claims 6 to 9, wherein a stream of data encoded using Huffman coding is decoded.
  5. 11
    A computer program product comprising computer program instructions to program a programmable processing apparatus to become operable to perform a method of decoding a stream of data (Fig. 82) comprising a plurality of variable-length code words, a plurality of not-encoded bit fields of variable-length, and a plurality of not-encoded bit fields of fixed length, wherein the variable-length code words are interleaved with the not-encoded bit fields of variable length and the not-encoded bit fields of fixed length, the method comprising:a preprocess of removing the plurality of not-encoded bit fields of fixed length from the stream of data and outputting the variable-length code words interleaved with the not-encoded bit fields of variable length as output blocks of data to be decoded;and a decoding process of decoding the variable-length code words in the blocks of data to be decoded and outputting decoded data to an output;characterised in that : the preprocess generates and outputs signals indicating the positions within the output blocks of data of the removed not-encoded bit fields of fixed length;and the method further comprises: using the signals indicating the positions of the removed not-encoded bit fields of fixed length to detect and remove the not-encoded variable-length bit fields from the blocks of data to be decoded;and passing the signals indicating the positions to the output in synchronisation with the data being decoded such that, if there is a multiplicity of the variable-length code words between the not-encoded bit fields of fixed length in the input data stream, then a multiplicity of corresponding decoded data is generated at the output between signals indicating positions corresponding to the not-encoded bit fields of fixed length in the input data stream.
Independent claims5