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/* RT binaural filter: earplug~ */
/* based on KEMAR impulse measurement */
/* Pei Xiang, summer 2004 */
/* Revised in Fall 2006 by Jorge Castellanos */
/* Revised in Spring 2009 by Hans-Christoph Steiner to compile in the data file */
#include <stdio.h>
#include <math.h>
#include "m_pd.h"
#include "earplug~.h"
#ifdef _MSC_VER /* Thes pragmas only apply to Microsoft's compiler */
#pragma warning( disable : 4244 )
#pragma warning( disable : 4305 )
#endif
/* elevation degree: -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 */
/* index array: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 */
/* impulse reponse number: 29 31 37 37 37 37 37 31 29 23 19 13 7 1 */
/* 0 degree reponse index: 0 29 60 97 134 171 208 245 276 305 328 347 360 367 */
static t_class *earplug_class;
typedef struct _earplug
{
t_object x_obj;
t_outlet *left_channel ;
t_outlet *right_channel ;
t_float azimuth ; /* from 0 to 360 degrees */
t_float elevation ; /* from -40 to 90 (degrees) */
t_float azi ;
t_float ele ;
t_float crossCoef[8192] ;
t_float azimScale[13] ;
t_int azimOffset[13] ;
t_float previousImpulse[2][128] ;
t_float currentImpulse[2][128] ;
t_float convBuffer[128] ;
t_float (*impulses)[2][128]; /* a 3D array of 368x2x128 */
t_float f ; /* dummy float for dsp */
t_int bufferPin;
} t_earplug;
static t_int *earplug_perform(t_int *w)
{
t_earplug *x = (t_earplug *)(w[1]) ;
t_float *in = (t_float *)(w[2]);
t_float *right_out = (t_float *)(w[3]);
t_float *left_out = (t_float *)(w[4]);
int blocksize = (int)(w[5]);
unsigned ch_L, ch_R, i;
x->azi = x->azimuth ;
x->ele = x->elevation ;
if (x->ele < -40)
x->ele = -40;
if (x->ele > 90)
x->ele = 90;
if (x->azi < 0 || x->azi > 360)
x->azi = 0;
if (x->azi <= 180)
{
ch_L = 0;
ch_R = 1;
}
else
{
ch_L = 1;
ch_R = 0;
x->azi = 360.0 - x->azi;
}
x->ele *= 0.1; /* divided by 10 since each elevation is 10 degrees apart */
if (x->ele < 8.) // if elevation is less than 80 degrees...
{
int elevInt = (int)floor(x->ele); // A quantized version of the elevation
unsigned elevGridIndex = elevInt + 4; // Used as the index to the array of scaling factors for the azimuth (adding 4 because the lowest elevation is -4, so it starts at 0)
unsigned azimIntUp = (unsigned)(x->azi * x->azimScale[elevGridIndex+1]); //
float azimFracUp = azimIntUp + 1.0 - x->azi * x->azimScale[elevGridIndex+1];
float azimFracUpInv = 1.0 - azimFracUp;
float elevFracUp = x->ele - elevInt * 1.0;
unsigned azimIntDown = (unsigned)(x->azi * x->azimScale[elevGridIndex]);
float azimFracDown = azimIntDown + 1.0 - x->azi * x->azimScale[elevGridIndex];
float azimFracDownInv = 1.0 - azimFracDown;
float elevFracDown = 1.0 - elevFracUp;
unsigned lowerIdx = x->azimOffset[elevGridIndex] + azimIntDown;
unsigned upperIdx = x->azimOffset[elevGridIndex + 1] + azimIntUp;
for (i = 0; i < 128; i++)
{
x->currentImpulse[ch_L][i] = elevFracDown * // Interpolate the lower two HRIRs and multiply them by their "fraction"
(azimFracDown * x->impulses[lowerIdx][0][i] +
azimFracDownInv * x->impulses[lowerIdx + 1][0][i]) +
elevFracUp * // Interpolate the upper two HRIRs and multiply them by their "fraction"
(azimFracUp * x->impulses[upperIdx][0][i] +
azimFracUpInv * x->impulses[upperIdx + 1][0][i]);
x->currentImpulse[ch_R][i] = elevFracDown *
(azimFracDown * x->impulses[lowerIdx][1][i] +
azimFracDownInv * x->impulses[lowerIdx + 1][1][i]) +
elevFracUp *
(azimFracUp * x->impulses[upperIdx][1][i] +
azimFracUpInv * x->impulses[upperIdx + 1][1][i]);
}
}
else // if elevation is 80 degrees or more the interpolation requires only three points (because there's only one HRIR at 90 deg)
{
unsigned azimIntDown = (unsigned)(x->azi * 0.033333); // Scale the azimuth to 12 (the number of HRIRs at 80 deg) discreet points
float azimFracDown = azimIntDown + 1.0 - x->azi * 0.033333;
float elevFracUp = x->ele - 8.0;
float elevFracDown = 9.0 - x->ele;
for (i = 0; i < 128; i++) {
x->currentImpulse[ch_L][i] = elevFracDown *
( azimFracDown * x->impulses[360+azimIntDown][0][i] + // These two lines interpolate the lower two HRIRs
(1.0 - azimFracDown) * x->impulses[361+azimIntDown][0][i] )
+ elevFracUp * x->impulses[367][0][i]; // multiply the 90 degree HRIR with its corresponding fraction
x->currentImpulse[ch_R][i] = elevFracDown *
(azimFracDown * x->impulses[360+azimIntDown][1][i] +
(1.0 - azimFracDown) * x->impulses[361+azimIntDown][1][i])
+ elevFracUp * x->impulses[367][1][i];
}
}
float inSample;
float convSum[2]; // to accumulate the sum during convolution.
int blockScale = 8192 / blocksize;
// Convolve the - interpolated - HRIRs (Left and Right) with the input signal.
while (blocksize--)
{
convSum[0] = 0;
convSum[1] = 0;
inSample = *(in++);
x->convBuffer[x->bufferPin] = inSample;
unsigned scaledBlocksize = blocksize * blockScale;
unsigned blocksizeDelta = 8191 - scaledBlocksize;
for (i = 0; i < 128; i++)
{
convSum[0] += (x->previousImpulse[0][i] * x->crossCoef[blocksizeDelta] +
x->currentImpulse[0][i] * x->crossCoef[scaledBlocksize]) *
x->convBuffer[(x->bufferPin - i) &127];
convSum[1] += (x->previousImpulse[1][i] * x->crossCoef[blocksizeDelta] +
x->currentImpulse[1][i] * x->crossCoef[scaledBlocksize]) *
x->convBuffer[(x->bufferPin - i) &127];
x->previousImpulse[0][i] = x->currentImpulse[0][i];
x->previousImpulse[1][i] = x->currentImpulse[1][i];
}
x->bufferPin = (x->bufferPin + 1) & 127;
*left_out++ = convSum[0];
*right_out++ = convSum[1];
}
return (w+6);
}
static void earplug_dsp(t_earplug *x, t_signal **sp)
{
// callback, params, userdata, in_samples, out_L, out_R, blocksize.
dsp_add(earplug_perform, 5, x, sp[0]->s_vec, sp[1]->s_vec, sp[2]->s_vec, sp[0]->s_n);
}
static void *earplug_new(t_floatarg azimArg, t_floatarg elevArg)
{
t_earplug *x = (t_earplug *)pd_new(earplug_class);
x->left_channel = outlet_new(&x->x_obj, gensym("signal"));
x->right_channel = outlet_new(&x->x_obj, gensym("signal"));
floatinlet_new(&x->x_obj, &x->azimuth) ; /* 0 to 360 degrees */
floatinlet_new(&x->x_obj, &x->elevation) ; /* -40 to 90 degrees */
x->azimuth = azimArg ;
x->elevation = elevArg ;
int i, j;
FILE *fp;
char buff[1024], *bufptr;
int filedesc;
filedesc = open_via_path(canvas_getdir(canvas_getcurrent())->s_name, "earplug_data.txt", "", buff, &bufptr, 1024, 0 );
if (filedesc >= 0) // If there was no error opening the text file...
{
post("[earplug~] found impulse reponse file, overriding defaults:") ;
post("let's try loading %s/earplug_data.txt", buff);
fp = fdopen(filedesc, "r") ;
for (i = 0; i < 368; i++)
{
while(fgetc(fp) != 10) ;
for (j = 0 ; j < 128 ; j++) {
fscanf(fp, "%f %f ", &earplug_impulses[i][0][j], &earplug_impulses[i][1][j]);
}
}
fclose(fp) ;
}
x->impulses = earplug_impulses;
post(" earplug~: binaural filter with measured reponses\n") ;
post(" elevation: -40 to 90 degrees. azimuth: 360") ;
post(" dont let blocksize > 8192\n");
for (i = 0; i < 128 ; i++)
{
x->convBuffer[i] = 0;
x->previousImpulse[0][i] = 0;
x->previousImpulse[1][i] = 0;
}
x->bufferPin = 0;
for (i = 0; i < 8192 ; i++)
{
x->crossCoef[i] = 1.0 * i / 8192;
}
// This is the scaling factor for the azimuth so that it corresponds to an HRTF in the KEMAR database
x->azimScale[0] = 0.153846153; x->azimScale[8] = 0.153846153; /* -40 and 40 degree */
x->azimScale[1] = 0.166666666; x->azimScale[7] = 0.166666666; /* -30 and 30 degree */
x->azimScale[2] = 0.2; x->azimScale[3]=0.2; x->azimScale[4]=0.2; x->azimScale[5]=0.2; x->azimScale[6]=0.2; /* -20 to 20 degree */
x->azimScale[9] = 0.125; /* 50 degree */
x->azimScale[10] = 0.1; /* 60 degree */
x->azimScale[11] = 0.066666666; /* 70 degree */
x->azimScale[12] = 0.033333333; /* 80 degree */
x->azimOffset[0] = 0 ;
x->azimOffset[1] = 29 ;
x->azimOffset[2] = 60 ;
x->azimOffset[3] = 97 ;
x->azimOffset[4] = 134 ;
x->azimOffset[5] = 171 ;
x->azimOffset[6] = 208 ;
x->azimOffset[7] = 245 ;
x->azimOffset[8] = 276 ;
x->azimOffset[9] = 305 ;
x->azimOffset[10] = 328 ;
x->azimOffset[11] = 347 ;
x->azimOffset[12] = 360 ;
return (x);
}
void earplug_tilde_setup(void)
{
earplug_class = class_new(gensym("earplug~"), (t_newmethod)earplug_new, 0,
sizeof(t_earplug), CLASS_DEFAULT, A_DEFFLOAT, A_DEFFLOAT, 0);
CLASS_MAINSIGNALIN(earplug_class, t_earplug, f);
class_addmethod(earplug_class, (t_method)earplug_dsp, gensym("dsp"), 0);
}
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