Method and system for extracting audio features from an encoded bitstream for audio classification

A method for extracting audio features from an encoded bitstream for audio classification, the method comprising:

• partially decoding the encoded bitstream using a decoder to obtain spectral coefficients of the encoded bitstream for audio classification;
• obtaining uniform window block size spectral coefficients of the encoded bitstream by processing said spectral coefficients using a processor;
• extracting audio features based on the uniform window block spectral coefficients for audio classification,
• classifying the encoded bitstream using the audio features,
• wherein the extracting of the audio features comprises:
• calculating a global spectrum centroid based on the uniform window block spectral coefficients;
• and
• deriving a Successive Lower Centroid (SLC) feature by reducing a spectrum range of the global spectrum centroid to a range based on a predefined convergence threshold.

A system for extracting audio features from an encoded bitstream for audio classification, the system comprising:

• a decoder for partially decoding the encoded bitstream using a decoder to obtain spectral coefficients of the encoded bitstream for audio classification;
• a processor for obtaining uniform window block size spectral coefficients of the encoded bitstream by representing a short window block in the encoded bitstream by a mean value of absolute spectral coefficients over all the short windows in said short window block and then expanding dimensions of short window block size spectral coefficients of said short window block of the encoded bitstream to dimensions of long window block size spectral coefficients of said short window block of the encoded bitstream so as to obtain uniform window block size spectral coefficients;
• an audio feature extractor for extracting audio features based on the uniform window block spectral coefficients for audio classification;
• and
• a classifier for classifying the encoded bitstream using the audio features.

A system for extracting audio features from an encoded bitstream for audio classification, the system comprising:

• a decoder for partially decoding the encoded bitstream using a decoder to obtain spectral coefficients of the encoded bitstream for audio classification;
• a processor for obtaining uniform window block size spectral coefficients of the encoded bitstream by processing said spectral coefficients;
• an audio feature extractor for extracting audio features based on the uniform window block spectral coefficients for audio classification;
• and
• a classifier for classifying the encoded bitstream using the audio features,
• wherein the audio feature extractor calculates a global spectrum centroid based on the uniform window block spectral coefficients and derives a Successive Lower Centroid (SLC) feature by reducing a spectrum range of the global spectrum centroid to a range based on a predefined convergence threshold.