COMPARISON OF DIFFERENT IMPLEMENTATIONS OF MFCC

The performance of the Mel-Frequency Cepstrum Coefficients (MFCC) may be affected by (1) the number of filters, (2) the shape of filters, (3) the way that filters are spaced, and (4) the way that the power spectrum is warped. In this paper, several comparison experiments are done to find a best implementation. The traditional MFCC calculation excludes the 0 th coefficient for the reason that it is regarded as somewhat unreliable. According to the analysis and experiments, the authors find that it can be regarded as the generalized frequency band energy (FBE) and is hence useful, which results in the FBE-MFCC. The authors also propose a better analysis, namely the auto-regressive analysis, on the frame energy, which outperforms its 1 st and/or 2 nd order differential derivatives. Experiments across the 863 Speech Database show that, compared with the traditional MFCC with its corresponding auto-regressive analysis coefficients, the FBE-MFCC and the frame energy with their corresponding auto-regressive analysis coefficients form the best combination, reducing the Chinese syllable error rate (CSER) by about 10.0%, while the FBE-MFCC with the corresponding auto-regressive analysis coefficients reducing CSER by 2.5%. Comparison experiments are also done across a quite casual Chinese speech database, named Chinese Annotated Spontaneous Speech (CASS) corpus, the FBE-MFCC can reduce the error rate by about 2.9 % on an average