MDCT-Based Complex Prediction Stereo Coding

A decoder system for providing a stereo signal by complex prediction stereo coding, the decoder system comprising:

• an upmix stage adapted to generate the stereo signal based on first frequency-domain representations of a downmix signal and a residual signal, each of the first frequency-domain representations comprising first spectral components representing spectral content of the corresponding signal expressed in a first subspace of a multidimensional space, wherein the upmix stage:
• computes a second frequency-domain representation of the downmix signal based on the first frequency-domain representation thereof, the second frequency-domain representation comprising second spectral components representing spectral content of the signal expressed in a second subspace of the multidimensional space that includes a portion of the multidimensional space not included in the first subspace;
• computes a side signal by combining the first frequency-domain representation of the residual signal, the first frequency-domain representation of the downmix signal weighted by a real-valued part of a complex prediction coefficient encoded in a bit stream signal, and the second frequency domain representation of the downmix signal weighted by an imaginary-valued part of the complex prediction coefficient;
• and
• computes the stereo signal on the basis of the first frequency-domain representation of the downmix signal and the side signal,
• wherein the upmix stage is adapted to apply independent bandwidth limits for the downmix signal and the residual signal.