The present invention provides a method and system to improve the cookbook search algorithm used in a coding/decoding device or routine. The codebook search algorithm is performed by a processing system that allows for parallel execution of instructions, for example a DSP. An embodiment of the present invention provides a method for coding of a first waveform. First a plurality of vectors determined from a plurality of waveforms is stored in a memory. Next a minimum weighted error using a plurality of filter coefficients and the plurality of vectors is determined. The minimum weighted error gives a closest match between the first waveform and a second waveform synthesized from a selected vector of the plurality of vectors. Then an indication of said selected vector is provided as part of a code of the first waveform. The plurality of filter coefficients have added to them at least one duplicate filter coefficient such that the performance of determining the minimum weighted error is improved, by for example, at least one clock cycle.