Analysing decompressed audio with the 'Inverse Decoder' - towards an operative algorithm

摘要

Perceptual audio coding of high quality audio signals is nowadays widely used. To reproduce the audio data, thebitstream is expanded to an uncompressed audio format by the decoding algorithm. As shown previously, it is feasibleto recover the encoding compression parameters from the decoded audio signal and even to translate a decoded audiosignal back into its original bitstream representation. This technique is referred to as inverse decoding" and hasseveral interesting applications, including tandem-resistant re-encoding of audio signals. The paper illustrates practicalresults obtained by the rst working implementation of an Inverse Decoder" based on the popular MP3 coder.The performance of the algorithm is evaluated in terms of reconstruction precision and computational complexity.Finally, algorithmic issues are discussed.