O'Reilly logo

Spatial Audio Processing: MPEG Surround and Other Applications by Christof Faller, Jeroen Breebaart

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

4.5 Subjective performance

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 subjective quality at low bitrates (typically 12–48 kbps for stereo audio content) for BCC-enabled coders is typically significantly higher than conventional stereo or multi-channel coders.
  • With increasing parameter bitrate, the subjective quality saturates at a high, but not fully transparent level due to the limitations of the underlying parametric model.

images

Figure 4.10 Typical performance of a BCC-enhanced coder (solid line) in comparison with a conventional stereo coder (dashed line).

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 ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required