Fast Audio Feature Extraction From Compressed Audio Data

We describe an efficient system, which directly extracts features from compressed audio material. It consists of a time-frequency conversion method and a feature extraction algorithm. The conversion method provides the feature extraction algorithm with a suitable complex spectral representation directly from the compressed domain, and further allows to adjust its computational complexity. Several operating points using different computational complexities were tested with an MPEG audio identification system to evaluate the identification performance. Based on our implementations, we found that our direct conversion is about a factor of 1.6 to 3.3 faster than the conventional full decoding.