An apparatus comprising: a receiver configured to receive a bitstream that includes an encoded mid signal and encoded stereo parameter information, the encoded stereo parameter information representing: a first value of a stereo parameter, the first value associated with a first frequency range and determined using an encoder-side windowing scheme; and a second value of the stereo parameter, the second value associated with a second frequency range and determined using the encoder-side windowing scheme; a mid signal decoder configured to decode the encoded mid signal to generate a decoded mid signal; a transform unit configured to perform a transform operation on the decoded mid signal to generate a frequency-domain decoded mid signal using a decoder-side windowing scheme; a stereo decoder configured to decode the encoded stereo parameter information to determine the first value and the second value; a stereo parameter conditioner configured to selectively perform a conditioning operation on the first value and the second value to generate a conditioned value of the stereo parameter, the conditioned value associated with a particular frequency range that is a subset of the first frequency range or a subset of the second frequency range, wherein the stereo parameter conditioner selectively performs the conditioning operation based on a variation of values of one or more stereo parameters satisfying a variation threshold; an up-mixer configured to perform an up-mix operation on the frequency-domain decoded mid signal to generate a first frequency-domain output signal and a second frequency-domain output signal, the conditioned value applied to the frequency-domain decoded mid signal during the up-mix operation; and an output device configured to output a first output audio signal and a second output audio signal, the first output audio signal based on the first frequency-domain output signal and the second output audio signal based on the second frequency-domain output signal. a receiver configured to receive a bitstream that includes an encoded mid signal and encoded stereo parameter information, the encoded stereo parameter information representing: a first value of a stereo parameter, the first value associated with a first frequency range and determined using an encoder-side windowing scheme; and a second value of the stereo parameter, the second value associated with a second frequency range and determined using the encoder-side windowing scheme; a first value of a stereo parameter, the first value associated with a first frequency range and determined using an encoder-side windowing scheme; and a second value of the stereo parameter, the second value associated with a second frequency range and determined using the encoder-side windowing scheme; a mid signal decoder configured to decode the encoded mid signal to generate a decoded mid signal; a transform unit configured to perform a transform operation on the decoded mid signal to generate a frequency-domain decoded mid signal using a decoder-side windowing scheme; a stereo decoder configured to decode the encoded stereo parameter information to determine the first value and the second value; a stereo parameter conditioner configured to selectively perform a conditioning operation on the first value and the second value to generate a conditioned value of the stereo parameter, the conditioned value associated with a particular frequency range that is a subset of the first frequency range or a subset of the second frequency range, wherein the stereo parameter conditioner selectively performs the conditioning operation based on a variation of values of one or more stereo parameters satisfying a variation threshold; an up-mixer configured to perform an up-mix operation on the frequency-domain decoded mid signal to generate a first frequency-domain output signal and a second frequency-domain output signal, the conditioned value applied to the frequency-domain decoded mid signal during the up-mix operation; and an output device configured to output a first output audio signal and a second output audio signal, the first output audio signal based on the first frequency-domain output signal and the second output audio signal based on the second frequency-domain output signal.