Multiplet-based matrix mixing for high-channel count multichannel audio

摘要

A multiplet-based spatial matrixing codec and method for reducing channel counts (and thus bitrates) of high-channel count (seven or more channels) multichannel audio, optimizing audio quality by enabling tradeoffs between spatial accuracy and basic audio quality, and converting audio signal formats to playback environment configurations. An initial N channel count is reduced to M channels by spatial matrix mixing to a lower number of channels using multiplet pan laws. The multiplet pan laws include doublet, triplet, and quadruplet pan laws. For example, using a quadruplet pan law one of the N channels can be downmixed to four of the M channels to create a quadruplet channel. Spatial information as well and audio content is contained in the multiplet channels. During upmixing the downmixed channel is extracted from the multiplet channels using the corresponding multiplet pan law. The extracted channel then is rendered at any location within a playback environment.

主权项

1. A method performed by one or more processing devices for transmitting an input audio signal having N channels, comprising:
selecting M channels for a downmixed output audio signal based on a desired bitrate, where N and M are non-zero positive integers and N is greater than M; downmixing and encoding the N channels to the M channels using the one or more processing devices and a combination of multiplet pan laws to obtain a pulse code modulation (PCM) bed mix containing M multiplet-encoded channels; transmitting the PCM bed mix at or below the desired bitrate; separating the M multiplet-encoded channels; upmixing and decoding each of the M multiplet-encoded channels using the one or more processing devices and the combination of multiplet pan laws to extract the N channels from the M multiplet-encoded channels and obtain a resultant output audio signal having N channels, the upmixing further comprising:
selecting one of the M multiplet-encoded channels;performing spatial analysis on the selected M multiplet-encoded channel and extracting an output channel based on the spatial analysis and using an associated M multiplet pan law;repeating the spatial analysis and extraction for each remaining of the M multiplet-encoded channels to obtain the resultant output audio signal having N channels; and rendering the resultant output audio signal in a playback environment having a playback channel layout.