Improved Time Delay Analysis/Synthesis for Parametric Stereo Audio Coding
For parametric stereo and multi-channel audio coding, it has been proposed to use level difference, time difference, and coherence cues between audio channels to represent the perceptual spatial features of stereo and multi-channel audio signals. In practice, it has turned out that by merely considering level difference and coherence cues a high audio quality can already be achieved. Time difference cue analysis/synthesis did not contribute much to a higher audio quality, or, even decreases audio quality when not done properly. However, for binaural audio signals, e.g. binaural recordings or signals mixed with HRTFs, time differences play an important role. We investigate problems of time difference analysis/synthesis with such critical signals and propose algorithms for improving it. A subjective evalution indicates significant improvements over previous time difference analysis/synthesis.