The knowledge of glottal closure and opening instants (GCI/GOI) is useful for many speech analysis applications. A Pitch-synchronous waveform encoding of voice is one such application. In this paper, a dynamic programming is employed to solve for the global close/open phase segmentation based on the polynomial parametric waveform of the derivative glottal waveform and its quasi-periodicity. Not only does the algorithm identify GCIs, but also the elusive GOIs, and as a by-product, the parameters of the glottal excitation waveform. The results show its effectiveness compared with a classical method. Its application to parametric voice encoding which allows for simple time-pitch scaling as well as voicing quality conversion is demonstrated.