RESIDUAL ENCODING IN AN OBJECT-BASED AUDIO SYSTEM

摘要

Lossy compression and transmission of a downmixed composite signal having multiple tracks and objects, including a downmixed signal, is accomplished in a manner that reduces the bit-rate requirement as compared to redundant transmission or lossless compression, while reducing upmix artifacts. A compressed residual signal is generated and transmitted along with a compressed total mix and at least one compressed audio objects. In the reception and upmix aspect the invention decompresses a downmixed signal and other compressed objects, calculates an approximate upmix signal, and corrects specific base signals derived from the upmix, by subtracting a decompressed residual signal. The invention thus allows lossy compression to be used in combination with downmixed audio signals for transmission through a communication channel (or for storage). Upon later reception and upmix, additional base signals are recoverable in capable systems providing multi-object capability (while legacy systems can easily decode a total mix without upmix).

主权项

1. A method of decompressing and upmixing a compressed and downmixed, composite audio signal, comprising the steps:
receiving a compressed representation of a total mix signal C, a compressed representation of a residual signal Δ; and a set of compressed representations of respective object signals {Bi}; wherein the set of compressed representations of at least one object signal includes at least one compressed representation of a corresponding object signal Bi; decompressing the compressed representation of the total mix signal and the compressed representation of the residual signal, to obtain an approximate total mix signal C′; decompressing the compressed representation of the residual signal Δ to obtain a reconstructed residual signal; decompressing the set of compressed representations object signal {Bi} to obtain a set of object signals {Bi′}, said set having one or more object signals Bi′ as members; subtractively mixing the approximate total mix signal C′ and the complete set of object signals {Bi′} to obtain a first approximation of a base signal A′; and subtractively mixing the reconstructed residual signal with the first approximation of the base signal, to obtain an improved approximation of the base signal.