src/lib/resampler.cc

   1 /*
   2     Copyright (C) 2013-2015 Carl Hetherington <cth@carlh.net>
   3
   4     This file is part of DCP-o-matic.
   5
   6     DCP-o-matic is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     DCP-o-matic is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 */
  20
  21 #include "resampler.h"
  22 #include "audio_buffers.h"
  23 #include "exceptions.h"
  24 #include "compose.hpp"
  25 #include "dcpomatic_assert.h"
  26 #include <samplerate.h>
  27 #include <iostream>
  28 #include <cmath>
  29
  30 #include "i18n.h"
  31
  32 using std::cout;
  33 using std::pair;
  34 using std::make_pair;
  35 using std::runtime_error;
  36 using boost::shared_ptr;
  37
  38 /** @param in Input sampling rate (Hz)
  39  *  @param out Output sampling rate (Hz)
  40  *  @param channels Number of channels.
  41  */
  42 Resampler::Resampler (int in, int out, int channels)
  43         : _in_rate (in)
  44         , _out_rate (out)
  45         , _channels (channels)
  46 {
  47         int error;
  48         _src = src_new (SRC_SINC_BEST_QUALITY, _channels, &error);
  49         if (!_src) {
  50                 throw runtime_error (String::compose (N_("could not create sample-rate converter (%1)"), error));
  51         }
  52 }
  53
  54 Resampler::~Resampler ()
  55 {
  56         if (_src) {
  57                 src_delete (_src);
  58         }
  59 }
  60
  61 void
  62 Resampler::set_fast ()
  63 {
  64         src_delete (_src);
  65         _src = 0;
  66
  67         int error;
  68         _src = src_new (SRC_LINEAR, _channels, &error);
  69         if (!_src) {
  70                 throw runtime_error (String::compose (N_("could not create sample-rate converter (%1)"), error));
  71         }
  72 }
  73
  74 shared_ptr<const AudioBuffers>
  75 Resampler::run (shared_ptr<const AudioBuffers> in)
  76 {
  77         int in_frames = in->frames ();
  78         int in_offset = 0;
  79         int out_offset = 0;
  80         shared_ptr<AudioBuffers> resampled (new AudioBuffers (_channels, 0));
  81
  82         while (in_frames > 0) {
  83
  84                 /* Compute the resampled frames count and add 32 for luck */
  85                 int const max_resampled_frames = ceil ((double) in_frames * _out_rate / _in_rate) + 32;
  86
  87                 SRC_DATA data;
  88                 float* in_buffer = new float[in_frames * _channels];
  89
  90                 {
  91                         float** p = in->data ();
  92                         float* q = in_buffer;
  93                         for (int i = 0; i < in_frames; ++i) {
  94                                 for (int j = 0; j < _channels; ++j) {
  95                                         *q++ = p[j][in_offset + i];
  96                                 }
  97                         }
  98                 }
  99
 100                 data.data_in = in_buffer;
 101                 data.input_frames = in_frames;
 102
 103                 data.data_out = new float[max_resampled_frames * _channels];
 104                 data.output_frames = max_resampled_frames;
 105
 106                 data.end_of_input = 0;
 107                 data.src_ratio = double (_out_rate) / _in_rate;
 108
 109                 int const r = src_process (_src, &data);
 110                 if (r) {
 111                         delete[] data.data_in;
 112                         delete[] data.data_out;
 113                         throw EncodeError (
 114                                 String::compose (
 115                                         N_("could not run sample-rate converter (%1) [processing %2 to %3, %4 channels]"),
 116                                         src_strerror (r),
 117                                         in_frames,
 118                                         max_resampled_frames,
 119                                         _channels
 120                                         )
 121                                 );
 122                 }
 123
 124                 if (data.output_frames_gen == 0) {
 125                         delete[] data.data_in;
 126                         delete[] data.data_out;
 127                         break;
 128                 }
 129
 130                 resampled->ensure_size (out_offset + data.output_frames_gen);
 131                 resampled->set_frames (out_offset + data.output_frames_gen);
 132
 133                 {
 134                         float* p = data.data_out;
 135                         float** q = resampled->data ();
 136                         for (int i = 0; i < data.output_frames_gen; ++i) {
 137                                 for (int j = 0; j < _channels; ++j) {
 138                                         q[j][out_offset + i] = *p++;
 139                                 }
 140                         }
 141                 }
 142
 143                 in_frames -= data.input_frames_used;
 144                 in_offset += data.input_frames_used;
 145                 out_offset += data.output_frames_gen;
 146
 147                 delete[] data.data_in;
 148                 delete[] data.data_out;
 149         }
 150
 151         return resampled;
 152 }
 153
 154 shared_ptr<const AudioBuffers>
 155 Resampler::flush ()
 156 {
 157         shared_ptr<AudioBuffers> out (new AudioBuffers (_channels, 0));
 158         int out_offset = 0;
 159         int64_t const output_size = 65536;
 160
 161         float dummy[1];
 162         float* buffer = new float[output_size];
 163
 164         SRC_DATA data;
 165         data.data_in = dummy;
 166         data.input_frames = 0;
 167         data.data_out = buffer;
 168         data.output_frames = output_size;
 169         data.end_of_input = 1;
 170         data.src_ratio = double (_out_rate) / _in_rate;
 171
 172         int const r = src_process (_src, &data);
 173         if (r) {
 174                 delete[] buffer;
 175                 throw EncodeError (String::compose (N_("could not run sample-rate converter (%1)"), src_strerror (r)));
 176         }
 177
 178         out->ensure_size (out_offset + data.output_frames_gen);
 179
 180         float* p = data.data_out;
 181         float** q = out->data ();
 182         for (int i = 0; i < data.output_frames_gen; ++i) {
 183                 for (int j = 0; j < _channels; ++j) {
 184                         q[j][out_offset + i] = *p++;
 185                 }
 186         }
 187
 188         out_offset += data.output_frames_gen;
 189         out->set_frames (out_offset);
 190
 191         delete[] buffer;
 192         return out;
 193 }
 194
 195 void
 196 Resampler::reset ()
 197 {
 198         src_reset (_src);
 199 }