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rbj_bandpass_bw.c
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rbj_bandpass_bw.c
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#include <ladspa.h>
#define _GNU_SOURCE
#include <math.h>
#include <stdlib.h>
/* (b0/a0) + (b1/a0)*z^-1 + (b2/a0)*z^-2
* H(z) = ---------------------------------------
* 1 + (a1/a0)*z^-1 + (a2/a0)*z^-2
*
* b0 = alpha
* b1 = 0
* b2 = -alpha
* a0 = 1 + alpha
* a1 = -2 cos(omega)
* a2 = 1 - alpha
*
* omega = 2 * pi * fc / fs
* alpha = sin(omega) * sinh( log(2)/2 * bw * omega / sin(omega) )
* = sin(omega) / (2*Q)
*/
enum {
PORT_IN,
PORT_OUT,
PORT_FREQUENCY,
PORT_BANDWIDTH,
PORT_GAIN,
PORT_NPORTS
};
typedef struct {
LADSPA_Data m_sample_rate;
LADSPA_Data *m_pport[PORT_NPORTS];
LADSPA_Data m_z1;
LADSPA_Data m_z2;
LADSPA_Data m_log2d2;
} Bandpass_Data;
static LADSPA_Handle Bandpass_instantiate(
const struct _LADSPA_Descriptor *p_pDescriptor,
unsigned long p_sample_rate ){
Bandpass_Data *l_pBandpass = malloc( sizeof(Bandpass_Data) );
if( l_pBandpass ){
l_pBandpass->m_sample_rate = p_sample_rate;
l_pBandpass->m_z1 = 0.0f;
l_pBandpass->m_z2 = 0.0f;
l_pBandpass->m_log2d2 = logf(2.0f)/2.0f;
}
return (LADSPA_Handle)l_pBandpass;
}
static void Bandpass_connect_port(
LADSPA_Handle p_pInstance,
unsigned long p_port,
LADSPA_Data *p_pdata)
{
Bandpass_Data *l_pBandpass = (Bandpass_Data*)p_pInstance;
l_pBandpass->m_pport[p_port] = p_pdata;
}
static void Bandpass_run(
LADSPA_Handle p_pInstance,
unsigned long p_sample_count )
{
Bandpass_Data *l_pBandpass = (Bandpass_Data*)p_pInstance;
unsigned long l_sample;
LADSPA_Data *l_psrc = l_pBandpass->m_pport[PORT_IN];
LADSPA_Data *l_pdst = l_pBandpass->m_pport[PORT_OUT];
LADSPA_Data *l_psrc_end = l_psrc + p_sample_count;
LADSPA_Data l_omega = 2.0f*M_PIf* *l_pBandpass->m_pport[PORT_FREQUENCY] /
l_pBandpass->m_sample_rate;
LADSPA_Data l_sin_omega = sinf( l_omega );
LADSPA_Data l_alpha = l_sin_omega*sinhf(l_pBandpass->m_log2d2 *
*l_pBandpass->m_pport[PORT_BANDWIDTH] * l_omega/l_sin_omega);
LADSPA_Data l_a0 = 1.0f + l_alpha;
register LADSPA_Data l_a1 = -2.0f * cosf( l_omega ) / l_a0;
register LADSPA_Data l_a2 = (1.0f - l_alpha) / l_a0;
register LADSPA_Data l_b0 = l_alpha / l_a0;
register LADSPA_Data l_b2 = -l_alpha / l_a0;
register LADSPA_Data l_G = exp10f( *l_pBandpass->m_pport[PORT_GAIN] / 20.0f );
for(;l_psrc!=l_psrc_end;l_psrc++,l_pdst++){
register LADSPA_Data l_m = *l_psrc - l_a1*l_pBandpass->m_z1 - l_a2*l_pBandpass->m_z2;
*l_pdst = l_G*(l_m*l_b0 + l_pBandpass->m_z2*l_b2);
l_pBandpass->m_z2 = l_pBandpass->m_z1;
l_pBandpass->m_z1 = l_m;
}
}
static void Bandpass_cleanup( LADSPA_Handle p_pInstance )
{
free( p_pInstance );
}
static LADSPA_PortDescriptor Bandpass_PortDescriptors[]=
{
LADSPA_PORT_INPUT|LADSPA_PORT_AUDIO,
LADSPA_PORT_OUTPUT|LADSPA_PORT_AUDIO,
LADSPA_PORT_INPUT|LADSPA_PORT_CONTROL,
LADSPA_PORT_INPUT|LADSPA_PORT_CONTROL,
LADSPA_PORT_INPUT|LADSPA_PORT_CONTROL
};
static const char *Bandpass_PortNames[]=
{
"Input",
"Output",
"Frequency(Hz)",
"Bandwidth(octaves)",
"Gain(dBFS)"
};
static LADSPA_PortRangeHint Bandpass_PortRangeHints[]=
{
{0,0,0},
{0,0,0},
{LADSPA_HINT_BOUNDED_BELOW|LADSPA_HINT_BOUNDED_ABOVE|
LADSPA_HINT_LOGARITHMIC|LADSPA_HINT_DEFAULT_MIDDLE,
10.0f,20000.0f},
{LADSPA_HINT_BOUNDED_BELOW|LADSPA_HINT_BOUNDED_ABOVE|
LADSPA_HINT_DEFAULT_MIDDLE,
0.1f/12.0f,2.0f},
{LADSPA_HINT_BOUNDED_BELOW|LADSPA_HINT_BOUNDED_ABOVE|
LADSPA_HINT_DEFAULT_0,
-60.0f,24.0f}
};
LADSPA_Descriptor RBJBandpassBW_Descriptor=
{
5815,
"RBJ_bandpass_BW",
LADSPA_PROPERTY_HARD_RT_CAPABLE,
"Bandpass RBJ(BW)",
"Timothy William Krause",
"None",
PORT_NPORTS,
Bandpass_PortDescriptors,
Bandpass_PortNames,
Bandpass_PortRangeHints,
NULL,
Bandpass_instantiate,
Bandpass_connect_port,
NULL,
Bandpass_run,
NULL,
NULL,
NULL,
Bandpass_cleanup
};