#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
- // using fixed point math
- 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)
+framecnt_t
+LinearInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input, Sample *output)
{
// index in the input buffers
- nframes_t i = 0;
-
+ framecnt_t i = 0;
+
double acceleration;
double distance = 0.0;
-
+
if (_speed != _target_speed) {
acceleration = _target_speed - _speed;
} else {
acceleration = 0.0;
}
-
- printf("phase before: %lf\n", phase[channel]);
+
distance = phase[channel];
- for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
- i = distance;
+ for (framecnt_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] =
+ 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)
+framecnt_t
+CubicInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input, Sample *output)
{
- phase.push_back (0.0);
-}
+ // index in the input buffers
+ framecnt_t i = 0;
-void
-LinearInterpolation::remove_channel_from ()
-{
- phase.pop_back ();
-}
+ double acceleration;
+ double distance = 0.0;
+ if (_speed != _target_speed) {
+ acceleration = _target_speed - _speed;
+ } else {
+ acceleration = 0.0;
+ }
-void
-LinearInterpolation::reset()
-{
- for (size_t i = 0; i <= phase.size(); i++) {
- phase[i] = 0.0;
- }
-}
+ distance = phase[channel];
-LibSamplerateInterpolation::LibSamplerateInterpolation() : state (0)
-{
- _speed = 1.0;
-}
+ if (nframes < 3) {
+ /* no interpolation possible */
-LibSamplerateInterpolation::~LibSamplerateInterpolation()
-{
- for (size_t i = 0; i < state.size(); i++) {
- state[i] = src_delete (state[i]);
- }
-}
+ for (i = 0; i < nframes; ++i) {
+ output[i] = input[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);
- }
-}
+ return nframes;
+ }
-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);
- }
- }
-}
+ /* keep this condition out of the inner loop */
-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 ();
-}
+ if (input && output) {
-void
-LibSamplerateInterpolation::remove_channel_from ()
-{
- delete data.back ();
- data.pop_back ();
- delete state.back ();
- state.pop_back ();
- reset_state ();
-}
+ Sample inm1;
-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;
+ if (floor (distance) == 0.0) {
+ /* best guess for the fake point we have to add to be able to interpolate at i == 0:
+ .... maintain slope of first actual segment ...
+ */
+ inm1 = input[i] - (input[i+1] - input[i]);
+ } else {
+ inm1 = input[i-1];
+ }
+
+ for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
+
+ float f = floor (distance);
+ float fractional_phase_part = distance - f;
+
+ /* get the index into the input we should start with */
+
+ i = lrintf (f);
+
+ /* fractional_phase_part only reaches 1.0 thanks to float imprecision. In theory
+ it should always be < 1.0. If it ever >= 1.0, then bump the index we use
+ and back it off. This is the point where we "skip" an entire sample in the
+ input, because the phase part has accumulated so much error that we should
+ really be closer to the next sample. or something like that ...
+ */
+
+ if (fractional_phase_part >= 1.0) {
+ fractional_phase_part -= 1.0;
+ ++i;
+ }
+
+ // Cubically interpolate into the output buffer: keep this inlined for speed and rely on compiler
+ // optimization to take care of the rest
+ // shamelessly ripped from Steve Harris' swh-plugins (ladspa-util.h)
+
+ output[outsample] = input[i] + 0.5f * fractional_phase_part * (input[i+1] - inm1 +
+ fractional_phase_part * (4.0f * input[i+1] + 2.0f * inm1 - 5.0f * input[i] - input[i+2] +
+ fractional_phase_part * (3.0f * (input[i] - input[i+1]) - inm1 + input[i+2])));
+
+ distance += _speed + acceleration;
+ inm1 = input[i];
+ }
+
+ } else {
+
+ /* not sure that this is ever utilized - it implies that one of the input/output buffers is missing */
+
+ for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
+ distance += _speed + acceleration;
+ }
+ }
+
+ i = floor(distance);
+ phase[channel] = distance - floor(distance);
+
+ return i;
}
projects / ardour.git / blobdiff