Enhancement of principal to ambient energy ratio for PCA-based parametric audio coding

In this paper, we propose a method of restoring principal to ambient energy ratio (PAR) at the decoder in the principal component analysis (PCA)-based parametric audio coding. The conventional approach applies the post-scaling at the decoder using the energy information extracted from the input signal at the encoder. However, this approach has a problem that the relative energy of principal source in the reconstructed signal is smaller than the original signal and also affected by the panning angle of principal source.
To restore the PAR at the decoder, the proposed method estimates the post-scaling factors using parametric information extracted from PCA-based formulation. The objective and subjective results verify the performance improvement of proposed method.