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
  29 #include "i18n.h"
  30
  31 using std::cout;
  32 using std::pair;
  33 using std::make_pair;
  34 using std::runtime_error;
  35 using boost::shared_ptr;
  36
  37 /** @param in Input sampling rate (Hz)
  38  *  @param out Output sampling rate (Hz)
  39  *  @param channels Number of channels.
  40  */
  41 Resampler::Resampler (int in, int out, int channels)
  42         : _in_rate (in)
  43         , _out_rate (out)
  44         , _channels (channels)
  45 {
  46         int error;
  47         _src = src_new (SRC_SINC_BEST_QUALITY, _channels, &error);
  48         if (!_src) {
  49                 throw runtime_error (String::compose (N_("could not create sample-rate converter (%1)"), error));
  50         }
  51 }
  52
  53 Resampler::~Resampler ()
  54 {
  55         src_delete (_src);
  56 }
  57
  58 void
  59 Resampler::set_fast ()
  60 {
  61         src_delete (_src);
  62         int error;
  63         _src = src_new (SRC_LINEAR, _channels, &error);
  64         if (!_src) {
  65                 throw runtime_error (String::compose (N_("could not create sample-rate converter (%1)"), error));
  66         }
  67 }
  68
  69 shared_ptr<const AudioBuffers>
  70 Resampler::run (shared_ptr<const AudioBuffers> in)
  71 {
  72         int in_frames = in->frames ();
  73         int in_offset = 0;
  74         int out_offset = 0;
  75         shared_ptr<AudioBuffers> resampled (new AudioBuffers (_channels, 0));
  76
  77         while (in_frames > 0) {
  78
  79                 /* Compute the resampled frames count and add 32 for luck */
  80                 int const max_resampled_frames = ceil ((double) in_frames * _out_rate / _in_rate) + 32;
  81
  82                 SRC_DATA data;
  83                 data.data_in = new float[in_frames * _channels];
  84
  85                 {
  86                         float** p = in->data ();
  87                         float* q = data.data_in;
  88                         for (int i = 0; i < in_frames; ++i) {
  89                                 for (int j = 0; j < _channels; ++j) {
  90                                         *q++ = p[j][in_offset + i];
  91                                 }
  92                         }
  93                 }
  94
  95                 data.input_frames = in_frames;
  96
  97                 data.data_out = new float[max_resampled_frames * _channels];
  98                 data.output_frames = max_resampled_frames;
  99
 100                 data.end_of_input = 0;
 101                 data.src_ratio = double (_out_rate) / _in_rate;
 102
 103                 int const r = src_process (_src, &data);
 104                 if (r) {
 105                         delete[] data.data_in;
 106                         delete[] data.data_out;
 107                         throw EncodeError (
 108                                 String::compose (
 109                                         N_("could not run sample-rate converter (%1) [processing %2 to %3, %4 channels]"),
 110                                         src_strerror (r),
 111                                         in_frames,
 112                                         max_resampled_frames,
 113                                         _channels
 114                                         )
 115                                 );
 116                 }
 117
 118                 if (data.output_frames_gen == 0) {
 119                         break;
 120                 }
 121
 122                 resampled->ensure_size (out_offset + data.output_frames_gen);
 123                 resampled->set_frames (out_offset + data.output_frames_gen);
 124
 125                 {
 126                         float* p = data.data_out;
 127                         float** q = resampled->data ();
 128                         for (int i = 0; i < data.output_frames_gen; ++i) {
 129                                 for (int j = 0; j < _channels; ++j) {
 130                                         q[j][out_offset + i] = *p++;
 131                                 }
 132                         }
 133                 }
 134
 135                 in_frames -= data.input_frames_used;
 136                 in_offset += data.input_frames_used;
 137                 out_offset += data.output_frames_gen;
 138
 139                 delete[] data.data_in;
 140                 delete[] data.data_out;
 141         }
 142
 143         return resampled;
 144 }
 145
 146 shared_ptr<const AudioBuffers>
 147 Resampler::flush ()
 148 {
 149         shared_ptr<AudioBuffers> out (new AudioBuffers (_channels, 0));
 150         int out_offset = 0;
 151         int64_t const output_size = 65536;
 152
 153         float dummy[1];
 154         float* buffer = new float[output_size];
 155
 156         SRC_DATA data;
 157         data.data_in = dummy;
 158         data.input_frames = 0;
 159         data.data_out = buffer;
 160         data.output_frames = output_size;
 161         data.end_of_input = 1;
 162         data.src_ratio = double (_out_rate) / _in_rate;
 163
 164         int const r = src_process (_src, &data);
 165         if (r) {
 166                 delete[] buffer;
 167                 throw EncodeError (String::compose (N_("could not run sample-rate converter (%1)"), src_strerror (r)));
 168         }
 169
 170         out->ensure_size (out_offset + data.output_frames_gen);
 171
 172         float* p = data.data_out;
 173         float** q = out->data ();
 174         for (int i = 0; i < data.output_frames_gen; ++i) {
 175                 for (int j = 0; j < _channels; ++j) {
 176                         q[j][out_offset + i] = *p++;
 177                 }
 178         }
 179
 180         out_offset += data.output_frames_gen;
 181         out->set_frames (out_offset);
 182
 183         delete[] buffer;
 184         return out;
 185 }