2 * copyright (c) 2010 Sveriges Television AB <info@casparcg.com>
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4 * This file is part of CasparCG.
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6 * CasparCG is free software: you can redistribute it and/or modify
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7 * it under the terms of the GNU General Public License as published by
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8 * the Free Software Foundation, either version 3 of the License, or
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9 * (at your option) any later version.
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11 * CasparCG is distributed in the hope that it will be useful,
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 * GNU General Public License for more details.
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16 * You should have received a copy of the GNU General Public License
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17 * along with CasparCG. If not, see <http://www.gnu.org/licenses/>.
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20 #include "../../stdafx.h"
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22 #include "audio_mixer.h"
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24 #include <core/mixer/write_frame.h>
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25 #include <core/producer/frame/audio_transform.h>
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27 namespace caspar { namespace core {
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29 struct audio_mixer::implementation
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31 std::deque<std::vector<int16_t>> audio_data_;
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32 std::stack<core::audio_transform> transform_stack_;
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34 std::map<int, core::audio_transform> prev_audio_transforms_;
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35 std::map<int, core::audio_transform> next_audio_transforms_;
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37 const core::video_format_desc format_desc_;
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40 implementation(const core::video_format_desc& format_desc)
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41 : format_desc_(format_desc)
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43 transform_stack_.push(core::audio_transform());
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44 audio_data_.push_back(std::vector<int16_t>()); // One frame delay
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47 void begin(core::basic_frame& frame)
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49 transform_stack_.push(transform_stack_.top()*frame.get_audio_transform());
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52 void visit(const core::write_frame& frame)
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54 if(!transform_stack_.top().get_has_audio() || frame.audio_data().empty())
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57 const auto& audio_data = frame.audio_data();
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58 const auto tag = frame.tag(); // Get the identifier for the audio-stream.
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60 const auto next = transform_stack_.top();
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63 const auto it = prev_audio_transforms_.find(tag);
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64 if(it != prev_audio_transforms_.end())
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67 next_audio_transforms_[tag] = next; // Store all active tags, inactive tags will be removed in end_pass.
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69 if(next.get_gain() < 0.001 && prev.get_gain() < 0.001)
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72 static const int BASE = 1<<15;
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74 const auto next_gain = static_cast<int>(next.get_gain()*BASE);
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75 const auto prev_gain = static_cast<int>(prev.get_gain()*BASE);
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77 const int n_samples = audio_data_.back().size();
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81 tbb::blocked_range<size_t>(0, audio_data.size()),
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82 [&](const tbb::blocked_range<size_t>& r)
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84 for(size_t n = r.begin(); n < r.end(); ++n)
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86 const int sample_gain = (prev_gain - (prev_gain * n)/n_samples) + (next_gain * n)/n_samples;
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87 const int sample = (static_cast<int>(audio_data[n])*sample_gain)/BASE;
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88 audio_data_.back()[n] = static_cast<int16_t>((static_cast<int>(audio_data_.back()[n]) + sample) & 0xFFFF);
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94 void begin(const core::audio_transform& transform)
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96 transform_stack_.push(transform_stack_.top()*transform);
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101 transform_stack_.pop();
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104 std::vector<int16_t> mix()
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106 prev_audio_transforms_ = std::move(next_audio_transforms_);
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107 auto result = std::move(audio_data_.front());
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108 audio_data_.pop_front();
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109 audio_data_.push_back(std::vector<int16_t>(format_desc_.audio_samples_per_frame));
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110 return std::move(result);
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114 audio_mixer::audio_mixer(const core::video_format_desc& format_desc) : impl_(new implementation(format_desc)){}
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115 void audio_mixer::begin(core::basic_frame& frame){impl_->begin(frame);}
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116 void audio_mixer::visit(core::write_frame& frame){impl_->visit(frame);}
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117 void audio_mixer::end(){impl_->end();}
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118 std::vector<int16_t> audio_mixer::mix(){return impl_->mix();}
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119 audio_mixer& audio_mixer::operator=(audio_mixer&& other)
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121 impl_ = std::move(other.impl_);
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