-#include <stdint.h>
+/*
+ Copyright (C) 2012 Paul Davis
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include <limits>
#include <cstdio>
+#include <stdint.h>
+
#include "ardour/interpolation.h"
+#include "ardour/midi_buffer.h"
using namespace ARDOUR;
+using std::cerr;
+using std::endl;
-nframes_t
-FixedPointLinearInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
+CubicInterpolation::CubicInterpolation ()
+ : valid_z_bits (0)
{
- // 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 the_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 = the_phase >> 24;
- Sample fractional_phase_part = (the_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;
- }
-
- the_phase += phi + phi_delta;
- }
-
- last_phase[channel] = (the_phase & fractional_part_mask);
-
- // playback distance
- return i;
}
-void
-FixedPointLinearInterpolation::add_channel_to (int /*input_buffer_size*/, int /*output_buffer_size*/)
+samplecnt_t
+CubicInterpolation::interpolate (int channel, samplecnt_t input_samples, Sample *input, samplecnt_t & output_samples, Sample *output)
{
- last_phase.push_back (0);
-}
+ assert (input_samples > 0);
+ assert (output_samples > 0);
+ assert (input);
+ assert (output);
+ assert (phase.size () > channel);
+
+ _speed = fabs (_speed);
+
+ if (invalid (0)) {
+
+ /* z[0] not set. Two possibilities
+ *
+ * 1) we have just been constructed or ::reset()
+ *
+ * 2) we were only given 1 sample after construction or
+ * ::reset, and stored it in z[1]
+ */
+
+ if (invalid (1)) {
+
+ /* first call after construction or after ::reset */
+
+ switch (input_samples) {
+ case 1:
+ /* store one sample for use next time. We don't
+ * have enough points to interpolate or even
+ * compute the first z[0] value, but keep z[1]
+ * around.
+ */
+ z[1] = input[0]; validate (1);
+ output_samples = 0;
+ return 0;
+ case 2:
+ /* store two samples for use next time, and
+ * compute a value for z[0] that will maintain
+ * the slope of the first actual segment. We
+ * still don't have enough samples to interpolate.
+ */
+ z[0] = input[0] - (input[1] - input[0]); validate (0);
+ z[1] = input[0]; validate (1);
+ z[2] = input[1]; validate (2);
+ output_samples = 0;
+ return 0;
+ default:
+ /* We have enough samples to interpolate this time,
+ * but don't have a valid z[0] value because this is the
+ * first call after construction or ::reset.
+ *
+ * First point is based on a requirement to maintain
+ * the slope of the first actual segment
+ */
+ z[0] = input[0] - (input[1] - input[0]); validate (0);
+ break;
+ }
+ } else {
-void
-FixedPointLinearInterpolation::remove_channel_from ()
-{
- last_phase.pop_back ();
-}
+ /* at least one call since construction or
+ * after::reset, since we have z[1] set
+ *
+ * we can now compute z[0] as required
+ */
-void
-FixedPointLinearInterpolation::reset()
-{
- for (size_t i = 0; i <= last_phase.size(); i++) {
- last_phase[i] = 0;
- }
-}
+ z[0] = z[1] - (input[0] - z[1]); validate (0);
+ /* we'll check the number of samples we've been given
+ in the next switch() statement below, and either
+ just save some more samples or actual interpolate
+ */
+ }
-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;
+ assert (is_valid (0));
}
-
- distance = 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++;
+
+ switch (input_samples) {
+ case 1:
+ /* one more sample of input. find the right vX to store
+ it in, and decide if we're ready to interpolate
+ */
+ if (invalid (1)) {
+ z[1] = input[0]; validate (1);
+ /* still not ready to interpolate */
+ output_samples = 0;
+ return 0;
+ } else if (invalid (2)) {
+ /* still not ready to interpolate */
+ z[2] = input[0]; validate (2);
+ output_samples = 0;
+ return 0;
+ } else if (invalid (3)) {
+ z[3] = input[0]; validate (3);
+ /* ready to interpolate */
}
-
- if (input && output) {
- // Linearly interpolate into the output buffer
- output[outsample] =
- input[i] * (1.0f - fractional_phase_part) +
- input[i+1] * fractional_phase_part;
+ break;
+ case 2:
+ /* two more samples of input. find the right vX to store
+ them in, and decide if we're ready to interpolate
+ */
+ if (invalid (1)) {
+ z[1] = input[0]; validate (1);
+ z[2] = input[1]; validate (2);
+ /* still not ready to interpolate */
+ output_samples = 0;
+ return 0;
+ } else if (invalid (2)) {
+ z[2] = input[0]; validate (2);
+ z[3] = input[1]; validate (3);
+ /* ready to interpolate */
+ } else if (invalid (3)) {
+ z[3] = input[0]; validate (3);
+ /* ready to interpolate */
}
- distance += _speed + acceleration;
+ break;
+
+ default:
+ /* caller has given us at least enough samples to interpolate a
+ single value.
+ */
+ z[1] = input[0]; validate (1);
+ z[2] = input[1]; validate (2);
+ z[3] = input[2]; validate (3);
}
-
- i = floor(distance);
- phase[channel] = distance - floor(distance);
-
- return i;
-}
-nframes_t
-CubicInterpolation::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];
- 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++;
- }
-
- if (input && output) {
- // Cubically interpolate into the output buffer
- output[outsample] = cube_interp(fractional_phase_part, input[i-1], input[i], input[i+1], input[i+2]);
- }
- distance += _speed + acceleration;
- }
-
- i = floor(distance);
- phase[channel] = distance - floor(distance);
-
- return i;
-}
+ /* ready to interpolate using z[0], z[1], z[2] and z[3] */
-SplineInterpolation::SplineInterpolation()
-{
- // precompute LU-factorization of matrix A
- // see "Teubner Taschenbuch der Mathematik", p. 1105
- // We only need to calculate up to 20, because they
- // won't change any more above that
- _m[0] = 4.0;
- for (int i = 0; i <= 20 - 2; i++) {
- _l[i] = 1.0 / _m[i];
- _m[i+1] = 4.0 - _l[i];
- }
-}
+ assert (is_valid (0));
+ assert (is_valid (1));
+ assert (is_valid (2));
+ assert (is_valid (3));
-nframes_t
-SplineInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
-{
- // How many input samples we need
- nframes_t n = ceil (double(nframes) * _speed + phase[channel]);
-
- printf("======== n: %u nframes: %u input: %u, output: %u\n", n, nframes, uint32_t(input), uint32_t(output));
-
- if (n <= 3) {
- return 0;
- }
-
- double M[n], t[n-2];
-
- // natural spline: boundary conditions
- M[0] = 0.0;
- M[n - 1] = 0.0;
-
- if (input) {
- // solve L * t = d
- t[0] = 6.0 * (input[0] - 2*input[1] + input[2]);
- for (nframes_t i = 1; i <= n - 3; i++) {
- t[i] = 6.0 * (input[i] - 2*input[i+1] + input[i+2])
- - l(i-1) * t[i-1];
- }
-
- // solve U * M = t
- M[n-2] = t[n-3] / m(n-3);
- //printf(" M[%d] = %lf \n", n-1 ,M[n-1]);
- //printf(" M[%d] = %lf \n", n-2 ,M[n-2]);
- for (nframes_t i = n-4;; i--) {
- M[i+1] = (t[i]-M[i+2])/m(i);
- //printf(" M[%d] = %lf\n", i+1 ,M[i+1]);
- if ( i == 0 ) break;
- }
- M[1] = 0.0;
- M[n - 2] = 0.0;
- //printf(" M[%d] = %lf \n", 0 ,M[0]);
- }
-
- assert (M[0] == 0.0 && M[n-1] == 0.0);
-
- // now interpolate
- // 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];
- assert(distance >= 0.0 && distance < 1.0);
-
- for (nframes_t outsample = 0; outsample < nframes; outsample++) {
- i = floor(distance);
-
- double x = double(distance) - double(i);
-
- // if distance is something like 0.999999999999
- // it will get rounded to 1 in the conversion to float above
- while (x >= 1.0) {
- x -= 1.0;
- i++;
- }
-
- assert(x >= 0.0 && x < 1.0);
-
- if (input && output) {
- assert (i <= n-1);
- double a3 = (M[i+1] - M[i]) / 6.0;
- double a2 = M[i] / 2.0;
- double a1 = input[i+1] - input[i] - (M[i+1] + 2.0*M[i])/6.0;
- double a0 = input[i];
- // interpolate into the output buffer
- output[outsample] = ((a3*x + a2)*x + a1)*x + a0;
- //std::cout << "input[" << i << "/" << i+1 << "] = " << input[i] << "/" << input[i+1] << " distance: " << distance << " output[" << outsample << "] = " << output[outsample] << std::endl;
- }
- distance += _speed + acceleration;
- }
-
- i = floor(distance);
- phase[channel] = distance - floor(distance);
- assert (phase[channel] >= 0.0 && phase[channel] < 1.0);
- printf("Moved input frames: %u ", i);
-
- return i;
-}
+ /* we can use up to (input_samples - 2) of the input, so compute the
+ * maximum number of output samples that represents.
+ *
+ * Remember that the expected common case here is to be given
+ * input_samples that is substantially larger than output_samples,
+ * thus allowing us to always compute output_samples in one call.
+ */
-LibSamplerateInterpolation::LibSamplerateInterpolation() : state (0)
-{
- _speed = 1.0;
-}
+ const samplecnt_t output_from_input = floor ((input_samples - 2) / _speed);
-LibSamplerateInterpolation::~LibSamplerateInterpolation()
-{
- for (size_t i = 0; i < state.size(); i++) {
- state[i] = src_delete (state[i]);
- }
-}
+ /* limit output to either the caller's requested number or the number
+ * determined by the input size.
+ */
-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);
- }
-}
+ const samplecnt_t limit = std::min (output_samples, output_from_input);
-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);
- }
+ samplecnt_t outsample = 0;
+ double distance = phase[channel];
+ samplecnt_t used = floor (distance);
+ samplecnt_t i = 0;
+
+ while (outsample < limit) {
+
+ i = floor (distance);
+
+ /* this call may stop the loop from being vectorized */
+ float fractional_phase_part = fmod (distance, 1.0);
+
+ /* Cubically interpolate into the output buffer */
+ output[outsample++] = z[1] + 0.5f * fractional_phase_part *
+ (z[2] - z[0] + fractional_phase_part * (4.0f * z[2] + 2.0f * z[0] - 5.0f * z[1] - z[3] +
+ fractional_phase_part * (3.0f * (z[1] - z[2]) - z[0] + z[3])));
+
+ distance += _speed;
+
+ z[0] = z[1];
+ z[1] = input[i];
+ z[2] = input[i+1];
+ z[3] = input[i+2];
}
-}
-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 ();
+ output_samples = outsample;
+ phase[channel] = fmod (distance, 1.0);
+ return i - used;
}
void
-LibSamplerateInterpolation::remove_channel_from ()
+CubicInterpolation::reset ()
{
- SRC_DATA* d = data.back ();
- delete d;
- data.pop_back ();
- if (state.back ()) {
- src_delete (state.back ());
- }
- state.pop_back ();
- reset_state ();
+ Interpolation::reset ();
+ valid_z_bits = 0;
}
-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;
+samplecnt_t
+CubicInterpolation::distance (samplecnt_t nsamples)
+{
+ assert (phase.size () > 0);
+ return floor (floor (phase[0]) + (_speed * nsamples));
}
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