Although the subjective quality of a BCC scheme may depend on several design choices in the analysis and synthesis stages, as well as the choice of the mono coder, the fact that a parametric model for spatial properties is employed results in two generic, typical observations.
The typical performance characteristic for stereo content and a comparison with a conventional stereo coder is shown in Fig. 4.10. At bitrates below a certain point (in this example about 48 kbit/s) the BCC-enhanced coder outperforms the conventional stereo coder in terms of quality. For higher bitrates, however, the quality for the BCC-enhanced coder tends to saturate. The saturation results from the fact that BCC only restores statistical properties of the signals, and does not guarantee a full decoder-side waveform reconstruction. This quality limitation can be resolved by employing the concept of residual coding (see Chapter 6).
18.191.14.196