Patent ID: 8238562

Claim:
A method for encoding C input audio channels to generate E transmitted audio channel(s), the method comprising: (a) generating one or more cue codes for two or more of the C input channels; (b) downmixing the C input channels to generate the E transmitted channel(s), where C>E≧1; and (c) analyzing one or more of the C input channels and the E transmitted channel(s) to generate a flag indicating whether or not a decoder of the E transmitted channel(s) should perform envelope shaping during decoding of the E transmitted channel(s), wherein step (c) comprises performing one or more of transient detection, randomness detection, and tonality detection to generate the flag, wherein: the transient detection comprises detecting a transient in the one or more of the C input channels and the E transmitted channel(s), such that the flag is generated to indicate that the decoder should perform the envelope shaping if the transient is detected the randomness detection comprises detecting that temporal envelope of the one or more of the C input channels and the E transmitted channel(s) is fluctuating pseudo-randomly, such that the flag is generated to indicate that the decoder should perform the envelope shaping if pseudo-random fluctuation is detected; and the tonality detection comprises detecting that tonality of the one or more of the C input channels and the E transmitted channel(s) is higher than a specified threshold, such that the flag is generated to indicate that the decoder should perform the envelope shaping if high tonality is detected.