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#include <math.h>
#include <samplerate.h>
#include "ardour/types.h"
#ifndef __interpolation_h__
#define __interpolation_h__
namespace ARDOUR {
class Interpolation {
protected:
double _speed, _target_speed;
// the idea is that when the speed is not 1.0, we have to
// interpolate between samples and then we have to store where we thought we were.
// rather than being at sample N or N+1, we were at N+0.8792922
std::vector<double> phase;
public:
Interpolation () { _speed = 1.0; _target_speed = 1.0; }
~Interpolation () { phase.clear(); }
void set_speed (double new_speed) { _speed = new_speed; _target_speed = new_speed; }
void set_target_speed (double new_speed) { _target_speed = new_speed; }
double target_speed() const { return _target_speed; }
double speed() const { return _speed; }
void add_channel_to (int /*input_buffer_size*/, int /*output_buffer_size*/) { phase.push_back (0.0); }
void remove_channel_from () { phase.pop_back (); }
void reset () {
for (size_t i = 0; i < phase.size(); i++) {
phase[i] = 0.0;
}
}
};
class LinearInterpolation : public Interpolation {
protected:
public:
nframes_t interpolate (int channel, nframes_t nframes, Sample* input, Sample* output);
};
class CubicInterpolation : public Interpolation {
protected:
// shamelessly ripped from Steve Harris' swh-plugins (ladspa-util.h)
static inline float cube_interp(const float fr, const float inm1, const float
in, const float inp1, const float inp2)
{
return in + 0.5f * fr * (inp1 - inm1 +
fr * (4.0f * inp1 + 2.0f * inm1 - 5.0f * in - inp2 +
fr * (3.0f * (in - inp1) - inm1 + inp2)));
}
public:
nframes_t interpolate (int channel, nframes_t nframes, Sample* input, Sample* output);
};
} // namespace ARDOUR
#endif
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