An apparatus for generating a plurality of audio channels for a first speaker setup is characterized by an imaginary speaker determiner, an energy distribution calculator, a processor and a renderer. The imaginary speaker determiner is configured to determine a position of an imaginary speaker not contained in the first speaker setup to obtain a second speaker setup containing the imaginary speaker. The energy distribution calculator is configured to calculate an energy distribution from the imaginary speaker to the other speakers in the second speaker setup. The processor is configured to repeat the energy distribution to obtain a downmix information for a downmix from the second speaker setup to the first speaker setup. The renderer is configured to generate the plurality of audio channels using the downmix information.

Systems and methods discussed herein can change a frame of reference for a first spatial audio signal. The first spatial audio signal can include signal components representing audio information from different depths or directions relative to an audio capture location associated with an audio capture source device with a first frame of reference relative to an environment Changing the frame of reference can include receiving a component of the first spatial audio signal, receiving information about a second frame of reference relative to the same environment, determining a difference between the first and second frames of reference, and, using the determined difference between the first and second frames of reference, determining a first filter to use to generate at least one component of a second spatial audio signal that is based on the first spatial audio signal and is referenced to the second frame of reference.

Systems and methods discussed herein can change a frame of reference for a first spatial audio signal. The first spatial audio signal can include signal components representing audio information from different depths or directions relative to an audio capture location associated with an audio capture source device with a first frame of reference relative to an environment Changing the frame of reference can include receiving a component of the first spatial audio signal, receiving information about a second frame of reference relative to the same environment, determining a difference between the first and second frames of reference, and, using the determined difference between the first and second frames of reference, determining a first filter to use to generate at least one component of a second spatial audio signal that is based on the first spatial audio signal and is referenced to the second frame of reference.

A multi-channel decorrelator for providing a plurality of decorrelated signals on the basis of a plurality of decorrelator input signals is configured to premix a first set of N decorrelator input signals into a second set of K decorrelator input signals, wherein K<N. The multi-channel decorrelator is configured to provide a first set of K′ decorrelator output signals on the basis of the second set of K decorrelator input signals. The multi-channel decorrelator is further configured to upmix the first set of K′ decorrelator output signals into a second set of N′ decorrelator output signals, wherein N′>K′. The multi-channel decorrelator can be used in a multi-channel audio decoder. A multi-channel audio encoder provides complexity control information for the multi-channel decorrelator.

A multi-channel decorrelator for providing a plurality of decorrelated signals on the basis of a plurality of decorrelator input signals is configured to premix a first set of N decorrelator input signals into a second set of K decorrelator input signals, wherein K<N. The multi-channel decorrelator is configured to provide a first set of K′ decorrelator output signals on the basis of the second set of K decorrelator input signals. The multi-channel decorrelator is further configured to upmix the first set of K′ decorrelator output signals into a second set of N′ decorrelator output signals, wherein N′>K′. The multi-channel decorrelator can be used in a multi-channel audio decoder. A multi-channel audio encoder provides complexity control information for the multi-channel decorrelator.

In some examples, immersive audio rendering may include determining whether an audio signal includes a first content format including stereo content, or a second content format including multichannel or object-based content. In response to a determination that the audio signal includes the first content format, the audio signal may be routed to a first block that includes a low-frequency extension and a stereo to multichannel upmix to generate a resulting audio signal. Alternatively, the audio signal may be routed to another low-frequency extension to generate the resulting audio signal. The audio signal may be further processed by performing spatial synthesis on the resulting audio signal, and crosstalk cancellation on the spatial synthesized audio signal. Further, multiband-range compression may be performed on the crosstalk cancelled audio signal, and an output stereo signal may be generated based on the multiband-range compressed audio signal.

Embodiments of systems and methods are described for providing backwards compatibility for legacy devices that are unable to natively render non-channel based audio objects. These systems and methods can also be beneficially used to produce a reduced set of audio objects for compatible object-based decoders with low computing resources.

Embodiments of systems and methods are described for providing backwards compatibility for legacy devices that are unable to natively render non-channel based audio objects. These systems and methods can also be beneficially used to produce a reduced set of audio objects for compatible object-based decoders with low computing resources.

Audio signals are recorded with microphones receiving acoustic information from one or more directions. The corresponding audio signals can be pre-listened to in production studios. However, Higher Order Ambisonics (HOA) audio signals are matrixed in such a way that the matrixing prevents listening to the matrixed sound signals without dematrixing the matrixed sound signals. For enabling a sound engineer to listen to such a matrixed signal without full HOA decoding, an informative audio signal is added together with related side information data at encoding side to a selected part of the matrixed signal. This informative audio signal is removed before the inverse matrixing process at decoding side.

Audio signals are recorded with microphones receiving acoustic information from one or more directions. The corresponding audio signals can be pre-listened to in production studios. However, Higher Order Ambisonics (HOA) audio signals are matrixed in such a way that the matrixing prevents listening to the matrixed sound signals without dematrixing the matrixed sound signals. For enabling a sound engineer to listen to such a matrixed signal without full HOA decoding, an informative audio signal is added together with related side information data at encoding side to a selected part of the matrixed signal. This informative audio signal is removed before the inverse matrixing process at decoding side.