The spectrum interpolation synthesis model has recently been applied in the high quality synthesis of harmonic musical sounds. In this work we investigate the performance of the model in the compression of music signals. Efficient methods for the automatic analysis, parameter extraction and synthesis of musical signals are presented. The system is tested on several examples of segments from wind and bowed string instruments. It is found that typically a perceived quality matching the original is obtained even when large portions of the waveform are generated by interpolation, implying that a high degree of compression is possible. Further, there is a graceful degradation in quality as the extent of interpolation is increased which makes the model well suited for use in a scalable audio coding framework.

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Vocal music is characterized by a melodically salient singing voice accompanied by one or more instruments. With a pitched instrument background, multiple periodicities are simultaneously present and the task becomes one of identifying and tracking the vocal pitch based on pitch strength and smoothness constraints. Frequency domain harmonic matching methods can be applied to detect pitch via the harmonically related frequencies that fit the signal’s measured spectral peaks. The specific spectral fitness measure is expected to influence the performance of vocal pitch detection depending on the nature of the polyphonic mixture. In this work, we consider Indian classical music which provides important examples of singing voice accompanied by strongly pitched instruments. It is shown that the spectral fitness measure of the two-way mismatch method is well suited to track vocal pitch in the presence of the pitched percussion with its strong but sparse harmonic structure. The detected pitch is further used to obtain a measure of voicing that reliably discriminates vocal segments from purely instrumental regions.

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The suitability of optimal path finding methods for vocal melody extraction in polyphonic music is well recognized since they combine local pitch strength and temporal smoothness considerations in a global sense. However, when such single-F0 tracking systems are applied to sound mixtures in which pitched accompaniment is of comparable strength to the singing voice, they suffer from irrecoverable degradations. In this study we investigate the use of an optimal path finding method that is allowed to dynamically track multiple F0 paths, specifically two, through the F0 candidate space. It is shown that when such a system is applied to typical polyphonic mixtures with vocal solo the melodic information is indeed retrieved. Audio examples are available at http://www.ee.iitb.ac.in/daplab/DualF0TrackingResults_DAFx

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