This paper considers a melody extraction algorithm that estimates the melody in polyphonic audio using the harmonic
coded structure (HCS) to model melody in the minimum
mean-square-error (MMSE) sense. The HCS is harmonically modulated sinusoids with the amplitudes defined by a
set of codewords. The considered algorithm performs melody
extraction in two steps: i) pitch-candidate estimation and ii)
pitch-sequence identification. In the estimation step, pitch
candidates are estimated such that the HCS best represents
the polyphonic audio in the MMSE sense. In the identification step, a melody line is selected from many possible pitch
sequences based on the properties of melody line. Posterior
to the melody line selection, a smoothing process is applied
to refine spurious pitches and octave errors. The performance of the algorithm is evaluated and compared using the
ADC04 and the MIREX05 dataset. The results show that
the performance of the proposed algorithm is better than or
comparable to other algorithms submitted to MIREX2009.