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 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*/)
-{
- last_phase.push_back (0);
-}
-void
-FixedPointLinearInterpolation::remove_channel_from ()
+framecnt_t
+LinearInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input, Sample *output)
{
- last_phase.pop_back ();
-}
-
-void
-FixedPointLinearInterpolation::reset()
-{
- for (size_t i = 0; i <= last_phase.size(); i++) {
- last_phase[i] = 0;
- }
-}
+ // index in the input buffers
+ framecnt_t i = 0;
+ double acceleration = 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];
- for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
- i = floor(distance);
- Sample fractional_phase_part = distance - i;
+
+ for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
+ double const d = phase[channel] + outsample * (_speed + acceleration);
+ i = floor(d);
+ Sample fractional_phase_part = d - i;
if (fractional_phase_part >= 1.0) {
fractional_phase_part -= 1.0;
i++;
}
-
+
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;
}
- distance += _speed + acceleration;
}
-
+
+ double const distance = phase[channel] + nframes * (_speed + acceleration);
i = floor(distance);
- phase[channel] = distance - floor(distance);
-
+ phase[channel] = distance - i;
return i;
}
-nframes_t
-CubicInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
+framecnt_t
+CubicInterpolation::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;
+ 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;
-}
-SplineInterpolation::SplineInterpolation()
-{
- reset ();
-}
+ if (nframes < 3) {
+ /* no interpolation possible */
-void SplineInterpolation::reset()
-{
- Interpolation::reset();
- M[0] = 0.0;
- M[1] = 0.0;
- M[2] = 0.0;
-}
+ for (i = 0; i < nframes; ++i) {
+ output[i] = input[i];
+ }
-nframes_t
-SplineInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
-{
-
- // now interpolate
- // index in the input buffers
- nframes_t i = 0, delta_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) {
- // if i changed, recalculate coefficients
- if (delta_i == 1) {
- // if i changed, rotate the M's
- M[0] = M[1];
- M[1] = M[2];
- M[2] = 6.0 * (input[i] - 2.0*input[i+1] + input[i+2]) - 4.0*M[1] - M[0];
- printf("\ny[%d] = %lf\n", i, input[i]);
- printf("y[%d] = %lf\n", i+1, input[i+1]);
- printf("y[%d] = %lf\n\n", i+2, input[i+2]);
- printf("M[2] = %lf M[1] = %lf M[0] = %lf y-term: %lf M-term: %lf\n",
- M[2], M[1], M[0], 6.0 * (input[i] - 2.0*input[i+1] + input[i+2]),
- - 4.0*M[1] - M[0]);
- }
- double a3 = (M[1] - M[0]) / 6.0;
- double a2 = M[0] / 2.0;
- double a1 = input[i+1] - input[i] - (M[1] + 2.0*M[0]) / 6.0;
- double a0 = input[i];
- // interpolate into the output buffer
- output[outsample] = ((a3*x + a2)*x + a1)*x + a0;
- //printf( "input[%d/%d] = %lf/%lf distance: %lf output[%d] = %lf\n", i, i+1, input[i], input[i+1], distance, outsample, output[outsample]);
-
- }
- distance += _speed + acceleration;
-
- delta_i = floor(distance) - i;
+ return nframes;
}
-
- i = floor(distance);
- phase[channel] = distance - floor(distance);
- assert (phase[channel] >= 0.0 && phase[channel] < 1.0);
-
- return i;
-}
-LibSamplerateInterpolation::LibSamplerateInterpolation() : state (0)
-{
- _speed = 1.0;
-}
+ /* keep this condition out of the inner loop */
-LibSamplerateInterpolation::~LibSamplerateInterpolation()
-{
- for (size_t i = 0; i < state.size(); i++) {
- state[i] = src_delete (state[i]);
- }
-}
+ if (input && output) {
-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);
- }
-}
+ Sample inm1;
-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);
- }
- }
-}
+ 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];
+ }
-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 ();
-}
+ for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
-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 ();
-}
+ float f = floor (distance);
+ float fractional_phase_part = distance - f;
-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;
+ /* 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