Vector Base Amplitude Panning Library

Implementation of Vector-Base Amplitude Panning (VBAP) and variants for sound spatialization.

# Vector Base Amplitude Panning Library
#### A compact library implementing the Vector Base Amplitude Panning (VBAP) method and variants for sound spatialization.
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> Archontis Politis, 2015
> Department of Signal Processing and Acoustics, Aalto University, Finland
> [e-mail]
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This Matlab/Octave library was developed during my doctoral research in the [Communication Acoustics Research Group] (http://spa.aalto.fi/en/research/research_groups/communication_acoustics/), Aalto University, Finland. If you would like to reference the code, you can refer to my dissertation published [here](https://aaltodoc.aalto.fi/handle/123456789/22499):

Archontis Politis, Microphone array processing for parametric spatial audio techniques, 2016
Doctoral Dissertation, Department of Signal Processing and Acoustics, Aalto University, Finland

## Description

This is a compact Matlab/Octave library implementing vector-base amplitude
panning (VBAP) [ref.1], VBAP-base spreading of a panned source [ref.2&3],
and Multiple-direction amplitude panning (MDAP) [ref.3]. A function
implementing the variant vector-base intensity panning [ref.4] is also
included. Recently, both VBAP and VBIP have been additionaly used for the
design of robust ambisonic decoding matrices, see [ref.5&6].

The code is written by Archontis Politis, except the core vbap()
function contributed by Ville Pulkki, with small modifications by
Archontis Politis. The following code examples are meant to give a quick
idea how to use the library for common operations in amplitude panning,
such as triangulation of a 3D loudspeaker setup into loudspeaker triplets,
spreading of a panned source, construction of panning gain
tables, and panning a moving source in a real-time block processing context.

For a demonstration of the various function, see [http://research.spa.aalto.fi/projects/vbap-lib/vbap.html],
or go through the TEST_VBAP_SCRIPTS.m script. For more detailed information, check the help output of the functions
and the code itself.

The library contains the following main functions:

* findLsPairs: find sorted loudspeaker pairs from loudspeaker directions (for 2D layouts)
* findLSTriplets: find valid loudspeaker triangles from loudspeaker directions (for 3D layouts)
* invertLsMtx: precompute inversion of matrix of loudspeaker triplets or pairs, for use in VBAP
* getSpreadSrcDirs: get auxiliary source directions around panning direction, for source spreading and MDAP
* vbap: Return VBAP panning gains for multiple panning directions, with spread control if needed

Additionaly:

* plotTriangulation: Plots the loudspeaker triangulated mesh
* getGainTable: Construct a look-up VBAP gain table of VBAP for a specified regular grid
* vbip: Similar to VBAP, but implementing its energy-based variant (see [ref.4])
* getPValueResponse: Returns VBAP frequency-dependent normalization values, for approximate flat perceived response of a panned source in dry playback environments (see [ref.7])

For any questions, comments, corrections, or general feedback, please
contact [e-mail]

## References

[1] Pulkki, V. (1997). Virtual Sound Source Positioning Using Vector Base Amplitude Panning.
Journal of the Audio Engineering Society, 45(6), 456-466.

[2] Pulkki, V. (2000). Generic panning tools for MAX/MSP.
International Computer Music Conference (ICMC), Berlin, Germany

[3] Pulkki, V. (1999). Uniform Spreading of Amplitude Panned Sources.
IEEE Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA), New Paltz, NY, USA

[4] Jot, J.-M., Larcher V., Pernaux, J.-M. (1999). A comparative study of 3-D audio encoding and rendering techniques.
16th International Conference of the AES, Rovaniemi, Finland

[5] Zotter, F., Frank, M. (2012). All-Round Ambisonic Panning and Decoding.
Journal of the Audio Engineering Society, 60(10), 807-820.

[6] Epain, N., Jin, C.T., Zotter, F. (2014). Ambisonic Decoding With Constant Angular Spread.
Acta Acustica united with Acustica, 100(May), 928-936.

[7] Laitinen, M., Vilkamo, J., Jussila, K., Politis, A., Pulkki, V. (2014).
Gain normalization in amplitude panning as a function of frequency and room reverberance.
55th International Conference of the AES. Helsinki, Finland.