Methods are disclosed for improving sound localization of the human ear. In some embodiments, the method may include creating virtual movement of a plurality of localized sources by applying a periodic function to one or more location parameters of a head related transfer function (HRTF).

Audio spatialization and environment simulation

Parametric-stereo coding is a technique to efficiently code a stereo audio signal as a monaural signal plus a small amount of parametric overhead to describe the stereo image. The stereo properties are analyzed, encoded, and reinstated in a decoder according to spatial psychoacoustical principles. The monaural signal can be encoded using any (conventional) audio coder. Experiments show that the parameterized description of spatial properties enables a highly efficient, high-quality stereo audio representation.

/pdf/parametric-coding-of-stereo-audio-4fznz7nwhj.pdf

Parametric coding of stereo audio

Multiple channels of audio are combined either to a monophonic composite signal or to multiple channels of audio along with related auxiliary information from which multiple channels of audio are reconstructed, including improved downmixing of multiple audio channels to a monophonic audio signal or to multiple audio channels and improved decorrelation of multiple audio channels derived from a monophonic audio channel or from multiple audio channels. Aspects of the disclosed invention are usable in audio encoders, decoders, encode/decode systems, downmixers, upmixers, and decorrelators.

Multichannel audio coding

Reference LCAV-CONF-2005-031 URL: www.aes.org Record created on 2005-10-07, modified on 2016-08-08

/pdf/the-reference-model-architecture-for-mpeg-spatial-audio-44puy4f7zg.pdf

The Reference Model Architecture for MPEG Spatial Audio Coding

In 2004 the ISO/MPEG Audio standardization group started a new work item on efficient and backward-compatible coding of high-quality multichannel sound using parametric coding techniques. Finalized in the fall of 2006, the resulting MPEG Surround specification allows the transmission of surround sound at bit rates that have been commonly used for coding of mono or stereo sound. The results of the standardization process are summarized by describing the underlying ideas and providing an overview of the MPEG Surround technology. The performance of the scheme is characterized by the results of recent verification tests. These tests include several operation modes as they would be used in typical application scenarios to introduce multichannel audio into existing audio services.

/pdf/mpeg-surround-the-iso-mpeg-standard-for-efficient-and-3rognjg23n.pdf

MPEG Surround – the ISO/MPEG Standard for Efficient and Compatible Multi-Channel Audio Coding

Following the recent trend of employing parametric enhancement tools for increasing coding or spatial rendering efficiency, Spatial Audio Object Coding (SAOC) is one of the recent standardization activities in the MPEG audio group. SAOC is a technique for efficient coding and flexible, user-controllable rendering of multiple audio objects based on transmission of a mono or stereo downmix of the object signals. The SAOC system extends the MPEG Surround standard by re-using its spatial rendering capabilities. This paper will describe the chosen reference model architecture, the association between the different operational modes and applications, and the current status of the standardization process.

/pdf/spatial-audio-object-coding-saoc-the-upcoming-mpeg-standard-4brcg3xa5i.pdf

Spatial Audio Object Coding (SAOC) - The Upcoming MPEG Standard on Parametric Object Based Audio Coding

Parametric stereo coding is a technique to efficiently code a stereo audio signal as a monaural signal plus a small amount of stereo parameters. The monaural signal can be encoded using any audio coder. The stereo parameters can be embedded in the ancillary part of the mono bit stream creating backwards mono compatibility. In the decoder, first the monaural signal is decoded after which the stereo signal is reconstructed from the stereo parameters. In this paper, a low complexity decoder solution is described based on complex-modulated filter banks. Combinations of the parametric stereo decoder with both a parametric coding scheme and with aacPlus will be elucidated.

Low Complexity Parametric Stereo Coding

An audio encoder (109) has a hierarchical encoding structure and generates a data stream comprising one or more audio channels as well as parametric audio encoding data. The encoder (109) comprises an encoding structure processor (305) which inserts decoder tree structure data into the data stream. The decoder tree structure data comprises at least one data value indicative of a channel split characteristic for an audio channel at a hierarchical layer of the hierarchical decoder structure and may specifically specify the decoder tree structures to be applied by a decoder. A decoder (115) comprises a receiver (401) which receives the data stream and a decoder structure processor (405) for generating the hierarchical decoder structure in response to the decoder tree structure data. A decode processor (403) then generates output audio channels from the data stream using the hierarchical decoder structure.

Audio encoding and decoding

Compared to traditional waveform coding standards that employ subband or transform coding, parametric coding is regarded as a technique that allows even further reduction of bit rates. In response to a call for proposals by MPEG-4 in January 2001, Philips submitted a parametric coder targetting at a high quality level. Currently, this coder is improved in the course of the “MPEG-4 Extension 2” standardisation process. Recently, two enhancements have been made increasing the overall performance of the coder. These consist of an improved model for the noise object and a parametric stereo extension.

Erik Gosuinus Petrus Schuijers

Papers

Parametric coding of stereo audio

Spatial Audio Object Coding (SAOC) - The Upcoming MPEG Standard on Parametric Object Based Audio Coding

Low Complexity Parametric Stereo Coding

Audio encoding and decoding

Advances in parametric coding for high-quality audio