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