A method for decoding an encoded audio bitstream in an audio processing system is disclosed. The method includes extracting from the encoded audio bitstream a first waveform-coded signal comprising spectral coefficients corresponding to frequencies up to a first cross-over frequency for a time frame and performing parametric decoding at a second cross-over frequency for the time frame to generate a reconstructed signal. The second cross-over frequency is above the first cross-over frequency and the parametric decoding uses reconstruction parameters derived from the encoded audio bitstream to generate the reconstructed signal. The method also includes extracting from the encoded audio bitstream a second waveform-coded signal comprising spectral coefficients corresponding to a subset of frequencies above the first cross-over frequency for the time frame and interleaving the second waveform-coded signal with the reconstructed signal to produce an interleaved signal for the time frame.

A signal processor includes an input unit that receives a first audio signal and a second audio signal including mutually correlated components, a delay unit that delays the first audio signal received at the input unit by a prescribed delay time, a synthesis unit that synthesizes the first audio signal having been delayed by the delay unit with the second audio signal received at the input unit, and outputs a third audio signal resulting from synthesis, and a frequency band restriction unit that restricts a level of the first audio signal before the synthesis in a prescribed frequency band including a frequency of a dip occurring at a lowest frequency among a plurality of dips occurring in a frequency characteristic of the third audio signal as a result of the synthesis performed by the synthesis unit.

There is provided a method for enhancing dialog in a decoder of an audio system. The method comprises receiving a plurality of downmix signals being a downmix of a larger plurality of channels; receiving parameters for dialog enhancement being defined with respect to a subset of the plurality of channels that is downmixed into a subset of the plurality of downmix signals; upmixing the subset of downmix signals parametrically in order to reconstruct the subset of the plurality of channels with respect to which the parameters for dialog enhancement are defined; applying dialog enhancement to the subset of the plurality of channels with respect to which the parameters for dialog enhancement are defined using the parameters for dialog enhancement to provide at least one dialog enhanced signal; and subjecting the at least one dialog enhanced signal to mixing to provide dialog enhanced versions of the subset of downmix signals.

Provided are methods and apparatus for enhancing a signal-to-noise ratio. In an example, provided is an apparatus configured to modify audio to better match the way the human brain processes audio by modifying the audio to a form which takes advantage of human echolocation capabilities. When humans listen to audio, they subconsciously listen for an echo and thus subconsciously focus on listening to, and for, meaningful information in audio. The focus causes humans to ignore noise in the audio, which results in enhancing a signal-to-noise ratio.

Provided are an audio encoding method and apparatus and an audio decoding method and apparatus in which audio signals can be encoded or decoded so that sound images can be localized at any desired position for each object audio signal. The audio decoding method generating a third downmix signal by combining a first downmix signal extracted from a first audio signal and a second downmix signal extracted from a second audio signal; generating third object-based side information by combining first object-based side information extracted from the first audio signal and second object-based side information extracted from the second audio signal; converting the third object-based side information into channel-based side information; and generating a multi-channel audio signal using the third downmix signal and the channel-based side information.

An audio metadata providing apparatus and method and a multichannel audio data playback apparatus and method to support a dynamic format conversion are provided. Dynamic format conversion information may include information about a plurality of format conversion schemes that are used to convert a first format set by a writer of multichannel audio data into a second format that is based on a playback environment of the multichannel audio data and that are set for each of playback periods of the multichannel audio data. The audio metadata providing apparatus may provide audio metadata including the dynamic format conversion information. The multichannel audio data playback apparatus may identify the dynamic format conversion information from the audio metadata, may convert the first format of the multichannel audio data into the second format based on the identified dynamic format conversion information, and may play back the multichannel audio data with the second format.

A downmixer for downmixing at least two channels of a multichannel signal having the two or more channels includes: a processor for calculating a partial downmix signal from the at least two channels; a complementary signal calculator for calculating a complementary signal from the multichannel signal, the complementary signal being different from the partial downmix signal; and an adder for adding the partial downmix signal and the complementary signal to obtain a downmix signal of the multichannel signal.

Methods which uses interpolated primitive matrices to decode encoded audio to recover (losslessly) content of a multichannel audio program and/or to recover at least one downmix of such content, and encoding methods for generating such encoded audio. In some embodiments, a decoder performs interpolation on a set of seed primitive matrices to determine interpolated matrices for use in rendering channels of the program. Other aspects are a system or device configured to implement any embodiment of the method.

A method of processing an audio signal is provided. A decoding apparatus receives the audio signal, which includes a plurality of objects. The decoding apparatus further receives object information, object gain information, and object correlation information, preset presence information, preset number information, preset information based on the preset presence information and the preset number information, and preset rendering data. The preset information exists in a header region or in each frame. The decoding apparatus obtains a preset matrix from the user by an input unit of the audio decoding apparatus when the preset type information indicates the preset rendering data is defined by the user, and adjusts an output level of the plurality of objects for an output channel based on the object information and the preset matrix. The decoding apparatus outputs an adjusted audio signal including the plurality of objects with an adjusted output level.

Systems, methods, and apparatus for backward-compatible coding of a set of basis function coefficients that describe a sound field are presented.