libs/ardour/interpolation.cc

   1 #include <stdint.h>
   2 #include <cstdio>
   3
   4 #include "ardour/interpolation.h"
   5
   6 using namespace ARDOUR;
   7
   8 nframes_t
   9 FixedPointLinearInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
  10 {
  11         // the idea behind phase is that when the speed is not 1.0, we have to
  12         // interpolate between samples and then we have to store where we thought we were.
  13         // rather than being at sample N or N+1, we were at N+0.8792922
  14         // so the "phase" element, if you want to think about this way,
  15         // varies from 0 to 1, representing the "offset" between samples
  16         uint64_t        phase = last_phase[channel];
  17
  18         // acceleration
  19         int64_t  phi_delta;
  20
  21         // phi = fixed point speed
  22         if (phi != target_phi) {
  23                 phi_delta = ((int64_t)(target_phi - phi)) / nframes;
  24         } else {
  25                 phi_delta = 0;
  26         }
  27
  28         // index in the input buffers
  29         nframes_t   i = 0;
  30
  31         for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
  32                 i = phase >> 24;
  33                 Sample fractional_phase_part = (phase & fractional_part_mask) / binary_scaling_factor;
  34
  35                 if (input && output) {
  36                         // Linearly interpolate into the output buffer
  37                         output[outsample] =
  38                                 input[i] * (1.0f - fractional_phase_part) +
  39                                 input[i+1] * fractional_phase_part;
  40                 }
  41
  42                 phase += phi + phi_delta;
  43         }
  44
  45         last_phase[channel] = (phase & fractional_part_mask);
  46
  47         // playback distance
  48         return i;
  49 }
  50
  51 void
  52 FixedPointLinearInterpolation::add_channel_to (int input_buffer_size, int output_buffer_size)
  53 {
  54         last_phase.push_back (0);
  55 }
  56
  57 void
  58 FixedPointLinearInterpolation::remove_channel_from ()
  59 {
  60         last_phase.pop_back ();
  61 }
  62
  63 void
  64 FixedPointLinearInterpolation::reset()
  65 {
  66         for (size_t i = 0; i <= last_phase.size(); i++) {
  67                 last_phase[i] = 0;
  68         }
  69 }
  70
  71
  72 nframes_t
  73 LinearInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
  74 {
  75         // index in the input buffers
  76         nframes_t   i = 0;
  77
  78         double acceleration;
  79         double distance = 0.0;
  80
  81         if (_speed != _target_speed) {
  82                 acceleration = _target_speed - _speed;
  83         } else {
  84                 acceleration = 0.0;
  85         }
  86
  87         distance = phase[channel];
  88         //printf("processing channel: %d\n", channel);
  89         //printf("phase before: %lf\n", phase[channel]);
  90         for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
  91                 i = floor(distance);
  92                 Sample fractional_phase_part = distance - i;
  93                 if (fractional_phase_part >= 1.0) {
  94                         fractional_phase_part -= 1.0;
  95                         i++;
  96                 }
  97                 //printf("I: %u, distance: %lf, fractional_phase_part: %lf\n", i, distance, fractional_phase_part);
  98
  99                 if (input && output) {
 100                 // Linearly interpolate into the output buffer
 101                         output[outsample] =
 102                                 input[i] * (1.0f - fractional_phase_part) +
 103                                 input[i+1] * fractional_phase_part;
 104                 }
 105                 //printf("distance before: %lf\n", distance);
 106                 distance += _speed + acceleration;
 107                 //printf("distance after: %lf, _speed: %lf\n", distance, _speed);
 108         }
 109
 110         //printf("before assignment: i: %d, distance: %lf\n", i, distance);
 111         i = floor(distance);
 112         //printf("after assignment: i: %d, distance: %16lf\n", i, distance);
 113         phase[channel] = distance - floor(distance);
 114         //printf("speed: %16lf, i after: %d, distance after: %16lf, phase after: %16lf\n", _speed, i, distance, phase[channel]);
 115
 116         return i;
 117 }
 118
 119 void
 120 LinearInterpolation::add_channel_to (int input_buffer_size, int output_buffer_size)
 121 {
 122         phase.push_back (0.0);
 123 }
 124
 125 void
 126 LinearInterpolation::remove_channel_from ()
 127 {
 128         phase.pop_back ();
 129 }
 130
 131
 132 void
 133 LinearInterpolation::reset()
 134 {
 135         for (size_t i = 0; i <= phase.size(); i++) {
 136                 phase[i] = 0.0;
 137         }
 138 }
 139
 140 LibSamplerateInterpolation::LibSamplerateInterpolation() : state (0)
 141 {
 142         _speed = 1.0;
 143 }
 144
 145 LibSamplerateInterpolation::~LibSamplerateInterpolation()
 146 {
 147         for (size_t i = 0; i < state.size(); i++) {
 148                 state[i] = src_delete (state[i]);
 149         }
 150 }
 151
 152 void
 153 LibSamplerateInterpolation::set_speed (double new_speed)
 154 {
 155         _speed = new_speed;
 156         for (size_t i = 0; i < state.size(); i++) {
 157                 src_set_ratio (state[i], 1.0/_speed);
 158         }
 159 }
 160
 161 void
 162 LibSamplerateInterpolation::reset_state ()
 163 {
 164         printf("INTERPOLATION: reset_state()\n");
 165         for (size_t i = 0; i < state.size(); i++) {
 166                 if (state[i]) {
 167                         src_reset (state[i]);
 168                 } else {
 169                         state[i] = src_new (SRC_SINC_FASTEST, 1, &error);
 170                 }
 171         }
 172 }
 173
 174 void
 175 LibSamplerateInterpolation::add_channel_to (int input_buffer_size, int output_buffer_size)
 176 {
 177         SRC_DATA* newdata = new SRC_DATA;
 178
 179         /* Set up sample rate converter info. */
 180         newdata->end_of_input = 0 ;
 181
 182         newdata->input_frames  = input_buffer_size;
 183         newdata->output_frames = output_buffer_size;
 184
 185         newdata->input_frames_used = 0 ;
 186         newdata->output_frames_gen = 0 ;
 187
 188         newdata->src_ratio = 1.0/_speed;
 189
 190         data.push_back (newdata);
 191         state.push_back (0);
 192
 193         reset_state ();
 194 }
 195
 196 void
 197 LibSamplerateInterpolation::remove_channel_from ()
 198 {
 199         SRC_DATA* d = data.back ();
 200         delete d;
 201         data.pop_back ();
 202         if (state.back ()) {
 203                 src_delete (state.back ());
 204         }
 205         state.pop_back ();
 206         reset_state ();
 207 }
 208
 209 nframes_t
 210 LibSamplerateInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
 211 {
 212         if (!data.size ()) {
 213                 printf ("ERROR: trying to interpolate with no channels\n");
 214                 return 0;
 215         }
 216
 217         data[channel]->data_in     = input;
 218         data[channel]->data_out   = output;
 219
 220         data[channel]->input_frames  = nframes * _speed;
 221         data[channel]->output_frames = nframes;
 222         data[channel]->src_ratio         = 1.0/_speed;
 223
 224         if ((error = src_process (state[channel], data[channel]))) {
 225                 printf ("\nError : %s\n\n", src_strerror (error));
 226                 exit (1);
 227         }
 228
 229         //printf("INTERPOLATION: channel %d input_frames_used: %d\n", channel, data[channel]->input_frames_used);
 230
 231         return data[channel]->input_frames_used;
 232 }