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#include <stdint.h>
#include <cstdio>
#include "ardour/interpolation.h"
using namespace ARDOUR;
nframes_t
FixedPointLinearInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
{
// the idea behind phase 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
// so the "phase" element, if you want to think about this way,
// varies from 0 to 1, representing the "offset" between samples
uint64_t phase = last_phase[channel];
// acceleration
int64_t phi_delta;
// phi = fixed point speed
if (phi != target_phi) {
phi_delta = ((int64_t)(target_phi - phi)) / nframes;
} else {
phi_delta = 0;
}
// index in the input buffers
nframes_t i = 0;
for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
i = phase >> 24;
Sample fractional_phase_part = (phase & fractional_part_mask) / binary_scaling_factor;
if (input && output) {
// Linearly interpolate into the output buffer
output[outsample] =
input[i] * (1.0f - fractional_phase_part) +
input[i+1] * fractional_phase_part;
}
phase += phi + phi_delta;
}
last_phase[channel] = (phase & fractional_part_mask);
// playback distance
return i;
}
void
FixedPointLinearInterpolation::add_channel_to (int /*input_buffer_size*/, int /*output_buffer_size*/)
{
last_phase.push_back (0);
}
void
FixedPointLinearInterpolation::remove_channel_from ()
{
last_phase.pop_back ();
}
void
FixedPointLinearInterpolation::reset()
{
for (size_t i = 0; i <= last_phase.size(); i++) {
last_phase[i] = 0;
}
}
nframes_t
LinearInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
{
// index in the input buffers
nframes_t i = 0;
double acceleration;
double distance = 0.0;
if (_speed != _target_speed) {
acceleration = _target_speed - _speed;
} else {
acceleration = 0.0;
}
distance = phase[channel];
//printf("processing channel: %d\n", channel);
//printf("phase before: %lf\n", phase[channel]);
for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
i = floor(distance);
Sample fractional_phase_part = distance - i;
if (fractional_phase_part >= 1.0) {
fractional_phase_part -= 1.0;
i++;
}
//printf("I: %u, distance: %lf, fractional_phase_part: %lf\n", i, distance, fractional_phase_part);
if (input && output) {
// Linearly interpolate into the output buffer
output[outsample] =
input[i] * (1.0f - fractional_phase_part) +
input[i+1] * fractional_phase_part;
}
//printf("distance before: %lf\n", distance);
distance += _speed + acceleration;
//printf("distance after: %lf, _speed: %lf\n", distance, _speed);
}
//printf("before assignment: i: %d, distance: %lf\n", i, distance);
i = floor(distance);
//printf("after assignment: i: %d, distance: %16lf\n", i, distance);
phase[channel] = distance - floor(distance);
//printf("speed: %16lf, i after: %d, distance after: %16lf, phase after: %16lf\n", _speed, i, distance, phase[channel]);
return i;
}
void
LinearInterpolation::add_channel_to (int /*input_buffer_size*/, int /*output_buffer_size*/)
{
phase.push_back (0.0);
}
void
LinearInterpolation::remove_channel_from ()
{
phase.pop_back ();
}
void
LinearInterpolation::reset()
{
for (size_t i = 0; i <= phase.size(); i++) {
phase[i] = 0.0;
}
}
LibSamplerateInterpolation::LibSamplerateInterpolation() : state (0)
{
_speed = 1.0;
}
LibSamplerateInterpolation::~LibSamplerateInterpolation()
{
for (size_t i = 0; i < state.size(); i++) {
state[i] = src_delete (state[i]);
}
}
void
LibSamplerateInterpolation::set_speed (double new_speed)
{
_speed = new_speed;
for (size_t i = 0; i < state.size(); i++) {
src_set_ratio (state[i], 1.0/_speed);
}
}
void
LibSamplerateInterpolation::reset_state ()
{
printf("INTERPOLATION: reset_state()\n");
for (size_t i = 0; i < state.size(); i++) {
if (state[i]) {
src_reset (state[i]);
} else {
state[i] = src_new (SRC_SINC_FASTEST, 1, &error);
}
}
}
void
LibSamplerateInterpolation::add_channel_to (int input_buffer_size, int output_buffer_size)
{
SRC_DATA* newdata = new SRC_DATA;
/* Set up sample rate converter info. */
newdata->end_of_input = 0 ;
newdata->input_frames = input_buffer_size;
newdata->output_frames = output_buffer_size;
newdata->input_frames_used = 0 ;
newdata->output_frames_gen = 0 ;
newdata->src_ratio = 1.0/_speed;
data.push_back (newdata);
state.push_back (0);
reset_state ();
}
void
LibSamplerateInterpolation::remove_channel_from ()
{
SRC_DATA* d = data.back ();
delete d;
data.pop_back ();
if (state.back ()) {
src_delete (state.back ());
}
state.pop_back ();
reset_state ();
}
nframes_t
LibSamplerateInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
{
if (!data.size ()) {
printf ("ERROR: trying to interpolate with no channels\n");
return 0;
}
data[channel]->data_in = input;
data[channel]->data_out = output;
data[channel]->input_frames = nframes * _speed;
data[channel]->output_frames = nframes;
data[channel]->src_ratio = 1.0/_speed;
if ((error = src_process (state[channel], data[channel]))) {
printf ("\nError : %s\n\n", src_strerror (error));
exit (1);
}
//printf("INTERPOLATION: channel %d input_frames_used: %d\n", channel, data[channel]->input_frames_used);
return data[channel]->input_frames_used;
}
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