seam.ambisonic.lib

// ---
// description: A library for the exploration of Michael Gerzon's algorithms
// ---
//
// <!-- LICENSE: GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007 -->
//
// # gerzon.lib
//
// ```text
declare name "Ambisonic Elements Faust Library";
declare version "0.1";
declare author "Giuseppe Silvi";
declare license "CC4";

sam = library("seam.ambisonic.lib");

//================================================================= ENCODERS ===
//==============================================================================
//------------------------------------------------------------------------------
// MS STEREO TO FIRST ORDER B-FORMAT ENCODER
//------------------------------------------------------------------------------
// Converts a Mid-Side Stereo stream into Firts Order B-Format
//------------------------------------------------------------------------------
ms2bfmt(m,s) = w,x,y,z
with{
  w = (m+s/2);
  x = m;
  y = s;
  z = 0;
};

//------------------------------------------------------------------------------
// LR STEREO TO FIRST ORDER B-FORMAT ENCODER
//------------------------------------------------------------------------------
// Converts a Left-Right Stereo stream into Firts Order B-Format
//------------------------------------------------------------------------------
lr2bfmt(l,r) = w(l,r), x(l,r), y(l,r), z
with{
  w(l,r) = ((l+r)/2)*(1/sqrt(2));
  x(l,r) = ((l+r)/2);
  y(l,r) = ((l-r)/2);
  z = 0;
};

//================================================================= DECODERS ===
//==============================================================================
//------------------------------------------------------------------------------
// FIRST ORDER PLANAR B-FORMAT TO MONO DECODER
//------------------------------------------------------------------------------
// Converts a First Order Planar B-Format into mono first order signal
//
// #### Reference
// https://en.wikipedia.org/wiki/Ambisonics
//
// The B-format components can be combined to derive virtual microphones with
// any first-order polar pattern (omnidirectional, cardioid, hypercardioid,
// figure-of-eight or anything in between) pointing in any direction. Several
// such microphones with different parameters can be derived at the same time,
// to create coincident stereo pairs (such as a Blumlein) or surround arrays.
// A horizontal virtual microphone at horizontal angle Θ \Theta with pattern
// 0 ≤ p ≤ 1 0 \leq p \leq 1 is given by
//
// This virtual mic is free-field normalised, which means it has a constant
// gain of one for on-axis sounds. The illustration on the left shows some
// examples created with this formula. Virtual microphones can be manipulated
// in post-production: desired sounds can be picked out, unwanted ones
// suppressed, and the balance between direct and reverberant sound can be
// fine-tuned during mixing.
//
// #### Usage
//
// ```
// encoder(x) = hgroup("BFMT MONO-DECODER", x);
// azi = encoder(vslider("[01] Azimuth [style:knob]", 0, 0, 360, 0.1) : deg2rad : si.smoo);
// p = encoder(vslider("[02] Polar [style:knob]", 0.5, 0, 1, 0.01) : si.smoo);
// deg2rad = *(ma.PI/180);
// process = _,_,_ : pbf2hm(azi,p) : _;
// ```
//
// Where the four inputs are respectively:
// W,X,Y
//
// Where the output is a mono signal with modulable polar pattern:
// out: m
// polar pattern: p
//
//------------------------------------------------------------------------------
pbf2m(a,p) = p*(sqrt(2)*(_))+((1-p)*((_*cos(a))+(_*sin(a))));

//------------------------------------------------------------------------------
// FIRST ORDER B-FORMAT TO REGULAR POLYGON
//------------------------------------------------------------------------------
// Converts a First Order B-Format n mono first order signal on the edge of a
// polygon
//
// #### Reference
// https://en.wikipedia.org/wiki/Ambisonics
//
// #### Usage
//
// ```
// _,_,_ : bfmt2m : _
// ```
//
// Where the two inputs are respectively:
// W,X,Y,Z
//
// Where the output is a mono signal with modulable polar pattern:
// m
//
//------------------------------------------------------------------------------
pbf2poly(n,p) = polygon
  with{
      azi(n) = 360/(n) : deg2rad;
      polygon(n) = par(i, n, pbf2m);
};

//------------------------------------------------------------------------------
fuma2sn3d(W,X,Y,Z) = W*(1/sqrt(2)), X, Y, Z;
fuma2acn_sn3d(W,X,Y,Z) = fuma2sn3d(W,X,Y,Z) : _, ro.cross(2), _ : _,_, ro.cross(2);
//process = fuma2acn_sn3d;

aa = library("aanl.lib");
sf = library("all.lib");
an = library("analyzers.lib");
ba = library("basics.lib");
co = library("compressors.lib");
de = library("delays.lib");
dm = library("demos.lib");
dx = library("dx7.lib");
en = library("envelopes.lib");
fd = library("fds.lib");
fi = library("filters.lib");
ho = library("hoa.lib");
it = library("interpolators.lib");
ma = library("maths.lib");
mi = library("mi.lib");
ef = library("misceffects.lib");
os = library("oscillators.lib");
no = library("noises.lib");
pf = library("phaflangers.lib");
pl = library("platform.lib");
pm = library("physmodels.lib");
qu = library("quantizers.lib");
rm = library("reducemaps.lib");
re = library("reverbs.lib");
ro = library("routes.lib");
sp = library("spats.lib");
si = library("signals.lib");
so = library("soundfiles.lib");
sy = library("synths.lib");
ve = library("vaeffects.lib");
vl = library("version.lib");
wa = library("webaudio.lib");
wd = library("wdmodels.lib");