Matrix decoder with constant-power pairwise panning

摘要

A constant-power pairwise panning upmixing system and method for upmixing from a two-channel stereo signal to a multi-channel surround sound (having more than two channels). Each output channel is some combination of the two input channels. Closed-form solutions are used to calculate dematrixing coefficients that are used to weight each input channel. The dematrixing coefficients are computed based on an inter-channel level difference and an inter-channel phase difference between the two input signals. The weighted input channels then are mixed uniquely for each output channel to generate a surround sound output from the stereo input signal. Each dematrixing coefficient has an in-phase component and an out-of-phase component. The phase coefficients for each component vary in time and are based on the phase difference between the input signals. The resultant surround sound output faithfully simulates the audio content as originally mixed.

主权项

1. A method performed by one or more processing devices for upmixing a two-channel input audio signal having a first input channel and a second input channel into an upmixed multi-channel output audio signal having greater than two channels, comprising:
calculating a first dematrixing coefficient, denoted as a, and a second dematrixing coefficient, denoted as b, based on an inter-channel level difference, denoted as ICLD, and an inter-channel phase difference between the first and second input channels, denoted as ICPD, wherein the first dematrixing coefficient is a combination of an in-phase signal component and an out-of-phase signal component; calculating an estimated panning angle from the inter-channel level difference; calculating an in-phase coefficient and an out-of-phase coefficient based on the estimated panning angle, wherein the in-phase signal component is based on the inter-channel phase difference multiplied by the in-phase coefficient and the out-of-phase signal component is based on the inter-channel phase difference multiplied by the out-of-phase coefficient; multiplying the first input channel by the first dematrixing coefficient to generate a first sub-signal and the second input channel by the second dematrixing coefficient to generate a second sub-signal; mixing the first sub-signal and the second sub-signal in a linear manner to generate an output channel of the upmixed multi-channel output audio signal; and outputting the generated output channel for playback through speakers.