git.sesse.net Git - casparcg/blob - core/mixer/audio/audio_mixer.cpp

   1 /*\r
   2 * copyright (c) 2010 Sveriges Television AB <info@casparcg.com>\r
   3 *\r
   4 *  This file is part of CasparCG.\r
   5 *\r
   6 *    CasparCG is free software: you can redistribute it and/or modify\r
   7 *    it under the terms of the GNU General Public License as published by\r
   8 *    the Free Software Foundation, either version 3 of the License, or\r
   9 *    (at your option) any later version.\r
  10 *\r
  11 *    CasparCG is distributed in the hope that it will be useful,\r
  12 *    but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  13 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  14 *    GNU General Public License for more details.\r
  15 \r
  16 *    You should have received a copy of the GNU General Public License\r
  17 *    along with CasparCG.  If not, see <http://www.gnu.org/licenses/>.\r
  18 *\r
  19 */\r
  20 #include "../../stdafx.h"\r
  21 \r
  22 #include "audio_mixer.h"\r
  23 \r
  24 #include <core/mixer/write_frame.h>\r
  25 #include <core/producer/frame/audio_transform.h>\r
  26 \r
  27 namespace caspar { namespace core {\r
  28         \r
  29 struct audio_mixer::implementation\r
  30 {\r
  31         std::vector<int16_t> audio_data_;\r
  32         std::stack<core::audio_transform> transform_stack_;\r
  33 \r
  34         std::map<int, core::audio_transform> prev_audio_transforms_;\r
  35         std::map<int, core::audio_transform> next_audio_transforms_;\r
  36 \r
  37 public:\r
  38         implementation()\r
  39         {\r
  40                 transform_stack_.push(core::audio_transform());\r
  41         }\r
  42         \r
  43         void begin(const core::basic_frame& frame)\r
  44         {\r
  45                 transform_stack_.push(transform_stack_.top()*frame.get_audio_transform());\r
  46         }\r
  47 \r
  48         void visit(const core::write_frame& frame)\r
  49         {\r
  50                 if(!transform_stack_.top().get_has_audio())\r
  51                         return;\r
  52 \r
  53                 auto& audio_data = frame.audio_data();\r
  54                 auto tag = frame.tag(); // Get the identifier for the audio-stream.\r
  55 \r
  56                 if(audio_data_.empty())\r
  57                         audio_data_.resize(audio_data.size(), 0);\r
  58                 \r
  59                 auto next = transform_stack_.top();\r
  60                 auto prev = next;\r
  61 \r
  62                 auto it = prev_audio_transforms_.find(tag);\r
  63                 if(it != prev_audio_transforms_.end())\r
  64                         prev = it->second;\r
  65                                 \r
  66                 next_audio_transforms_[tag] = next; // Store all active tags, inactive tags will be removed in end_pass.\r
  67                                 \r
  68                 if(next.get_gain() < 0.001 && prev.get_gain() < 0.001)\r
  69                         return;\r
  70                 \r
  71                 static const int BASE = 1<<15;\r
  72 \r
  73                 auto next_gain = static_cast<int>(next.get_gain()*BASE);\r
  74                 auto prev_gain = static_cast<int>(prev.get_gain()*BASE);\r
  75                 \r
  76                 int n_samples = audio_data_.size();\r
  77 \r
  78                 tbb::parallel_for\r
  79                 (\r
  80                         tbb::blocked_range<size_t>(0, audio_data.size()),\r
  81                         [&](const tbb::blocked_range<size_t>& r)\r
  82                         {\r
  83                                 for(size_t n = r.begin(); n < r.end(); ++n)\r
  84                                 {\r
  85                                         int sample_gain = (prev_gain - (prev_gain * n)/n_samples) + (next_gain * n)/n_samples;\r
  86                                         \r
  87                                         int sample = (static_cast<int>(audio_data[n])*sample_gain)/BASE;\r
  88                                         \r
  89                                         audio_data_[n] = static_cast<int16_t>((static_cast<int>(audio_data_[n]) + sample) & 0xFFFF);\r
  90                                 }\r
  91                         }\r
  92                 );\r
  93         }\r
  94 \r
  95 \r
  96         void begin(const core::audio_transform& transform)\r
  97         {\r
  98                 transform_stack_.push(transform_stack_.top()*transform);\r
  99         }\r
 100                 \r
 101         void end()\r
 102         {\r
 103                 transform_stack_.pop();\r
 104         }\r
 105 \r
 106 \r
 107         std::vector<int16_t> mix()\r
 108         {\r
 109                 prev_audio_transforms_ = std::move(next_audio_transforms_);     \r
 110                 return std::move(audio_data_);\r
 111         }\r
 112 };\r
 113 \r
 114 audio_mixer::audio_mixer() : impl_(new implementation()){}\r
 115 void audio_mixer::begin(const core::basic_frame& frame){impl_->begin(frame);}\r
 116 void audio_mixer::visit(core::write_frame& frame){impl_->visit(frame);}\r
 117 void audio_mixer::end(){impl_->end();}\r
 118 std::vector<int16_t> audio_mixer::mix(){return impl_->mix();}\r
 119 \r
 120 }}