Discrete cosine transform method and apparatus

A linear transform apparatus for implementing a linear transform on input data values to produce linear transformed output data, the apparatus comprising:

• input means for inputting input data values one after another to a series of multiplication means;
• memory storage means for storing a predetermined series of constants, and outputting a number of said constants, as determined by a corresponding input data value index, to corresponding ones of said series of multiplication means;
• a series of multiplication means interconnected with said memory storage means and said input means for multiplying outputted constants stored in the memory means by a current input data value to produce a current multiplier output;
• a series of signed accumulator means each interconnected to a single corresponding multiplication means, said signed accumulator means producing an intermediate accumulator output by accumulating a corresponding said current multiplier output with a previous intermediate output, each of said signed accumulator means outputting said intermediate accumulator output as a corresponding linear transformed output data value.