RECONSTRUCTING AUDIO CHANNELS WITH A FRACTIONAL DELAY DECORRELATOR

摘要

A method performed by an audio decoder for reconstructing N audio channels from an audio signal containing M audio channels is disclosed. The method includes receiving a bitstream containing an encoded audio signal having M audio channels and a set of spatial parameters, the set of spatial parameters including an inter-channel intensity difference parameter and an inter-channel coherence parameter. The encoded audio bitstream is then decoded to obtain a decoded frequency domain representation of the M audio channels, and at least a portion of the frequency domain representation is decorrelated with an all-pass filter having a fractional delay. The all-pass filter is attenuated at locations of a transient. A matrixed version of the decorrelated signals are summed with a matrixed version of the decoded frequency domain representation to obtain N audio signals that collectively having N audio channels where M is less than N.

主权项

1. A method performed by an audio decoder for reconstructing N audio channels from an audio signal containing M audio channels, the method comprising:
receiving a bitstream containing an encoded audio signal having M audio channels and a set of spatial parameters, the set of spatial parameters including an inter-channel intensity difference parameter and an inter-channel coherence parameter; decoding the encoded audio signal having M audio channels to obtain a decoded representation of the M audio channels; decorrelating at least a portion of the decoded representation with an all-pass filter to obtain M decorrelated signals; reconstructing N audio channels by summing a matrixed version of the M decorrelated signals with a matrixed version of the decoded representation of the M audio channels to obtain N audio signals that collectively having N audio channels, wherein N is two or more, M is one or more, and M is less than N; and synthesizing the N audio signals with one or more synthesis filterbanks to convert the N audio signals from a frequency domain to a time domain, wherein the decorrelating includes attenuating the all-pass filter at locations of a transient, the all-pass filter has a fractional delay, and the audio decoder is implemented at least in part in hardware.