Parametric Coding of Piano Signals
In this paper an audio coding procedure for piano signals is presented based on a physical model of the piano. Instead of coding the waveform of the signal, the compression is realized by extracting relevant parameters at the encoder. The signal is then re-synthesized at the decoder using the physical model. We describe the development and implementation of algorithms for parameter extraction and the combination of all the components into a coder. A formal listening test was conducted, which shows that we can obtain a high sound quality at a low bit rate, lower than conventional coders. We obtain a bitrate of 11.6 kbps for the proposed piano coder. We use HE-AAC as reference codec at a gross bitrate of 16 kbps. For low and medium chords the proposed piano coder outperforms HE-AAC in terms of subjective quality, while the quality falls below HE-AAC for high chords.
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