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

   1 /*
   2 * Copyright (c) 2011 Sveriges Television AB <info@casparcg.com>
   3 *
   4 * This file is part of CasparCG (www.casparcg.com).
   5 *
   6 * CasparCG 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 3 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * CasparCG 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 CasparCG. If not, see <http://www.gnu.org/licenses/>.
  18 *
  19 * Author: Robert Nagy, ronag89@gmail.com
  20 */
  21
  22 #include "../../stdafx.h"
  23
  24 #include "audio_mixer.h"
  25
  26 #include <core/frame/frame.h>
  27 #include <core/frame/frame_transform.h>
  28 #include <common/diagnostics/graph.h>
  29
  30 #include <boost/range/adaptors.hpp>
  31 #include <boost/range/distance.hpp>
  32
  33 #include <map>
  34 #include <stack>
  35 #include <vector>
  36
  37 namespace caspar { namespace core {
  38
  39 struct audio_item
  40 {
  41         const void*                     tag;
  42         audio_transform         transform;
  43         audio_buffer            audio_data;
  44
  45         audio_item()
  46         {
  47         }
  48
  49         audio_item(audio_item&& other)
  50                 : tag(std::move(other.tag))
  51                 , transform(std::move(other.transform))
  52                 , audio_data(std::move(other.audio_data))
  53         {
  54         }
  55 };
  56
  57 typedef std::vector<float, tbb::cache_aligned_allocator<float>> audio_buffer_ps;
  58
  59 struct audio_stream
  60 {
  61         audio_transform         prev_transform;
  62         audio_buffer_ps         audio_data;
  63         bool                            is_still;
  64
  65         audio_stream()
  66                 : is_still(false)
  67         {
  68         }
  69 };
  70
  71 struct audio_mixer::impl : boost::noncopyable
  72 {
  73         std::stack<core::audio_transform>       transform_stack_;
  74         std::map<const void*, audio_stream>     audio_streams_;
  75         std::vector<audio_item>                         items_;
  76         std::vector<int>                                        audio_cadence_;
  77         video_format_desc                                       format_desc_;
  78
  79 public:
  80         impl()
  81         {
  82                 transform_stack_.push(core::audio_transform());
  83         }
  84
  85         void push(const frame_transform& transform)
  86         {
  87                 transform_stack_.push(transform_stack_.top()*transform.audio_transform);
  88         }
  89
  90         void visit(const const_frame& frame)
  91         {
  92                 if(transform_stack_.top().volume < 0.002 || frame.audio_data().empty())
  93                         return;
  94
  95                 audio_item item;
  96                 item.tag                = frame.stream_tag();
  97                 item.transform  = transform_stack_.top();
  98                 item.audio_data = frame.audio_data();
  99
 100                 if(item.transform.is_still)
 101                         item.transform.volume = 0.0;
 102
 103                 items_.push_back(std::move(item));
 104         }
 105
 106         void begin(const core::audio_transform& transform)
 107         {
 108                 transform_stack_.push(transform_stack_.top()*transform);
 109         }
 110
 111         void pop()
 112         {
 113                 transform_stack_.pop();
 114         }
 115
 116         audio_buffer mix(const video_format_desc& format_desc)
 117         {
 118                 if(format_desc_ != format_desc)
 119                 {
 120                         audio_streams_.clear();
 121                         audio_cadence_ = format_desc.audio_cadence;
 122                         format_desc_ = format_desc;
 123                 }
 124
 125                 std::map<const void*, audio_stream>     next_audio_streams;
 126                 std::vector<const void*> used_tags;
 127
 128                 BOOST_FOREACH(auto& item, items_)
 129                 {
 130                         audio_buffer_ps next_audio;
 131
 132                         auto next_transform = item.transform;
 133                         auto prev_transform = next_transform;
 134
 135                         auto tag = item.tag;
 136
 137                         if(boost::range::find(used_tags, tag) != used_tags.end())
 138                                 continue;
 139
 140                         used_tags.push_back(tag);
 141
 142                         const auto it = audio_streams_.find(tag);
 143                         if(it != audio_streams_.end())
 144                         {
 145                                 prev_transform  = it->second.prev_transform;
 146                                 next_audio              = std::move(it->second.audio_data);
 147                         }
 148
 149                         // Skip it if there is no existing audio stream and item has no audio-data.
 150                         if(it == audio_streams_.end() && item.audio_data.empty())
 151                                 continue;
 152
 153                         const float prev_volume = static_cast<float>(prev_transform.volume);
 154                         const float next_volume = static_cast<float>(next_transform.volume);
 155
 156                         // TODO: Move volume mixing into code below, in order to support audio sample counts not corresponding to frame audio samples.
 157                         auto alpha = (next_volume-prev_volume)/static_cast<float>(item.audio_data.size()/format_desc.audio_channels);
 158
 159                         for(size_t n = 0; n < item.audio_data.size(); ++n)
 160                                 next_audio.push_back(item.audio_data[n] * (prev_volume + (n/format_desc_.audio_channels) * alpha));
 161
 162                         next_audio_streams[tag].prev_transform  = std::move(next_transform); // Store all active tags, inactive tags will be removed at the end.
 163                         next_audio_streams[tag].audio_data              = std::move(next_audio);
 164                         next_audio_streams[tag].is_still                = item.transform.is_still;
 165                 }
 166
 167                 items_.clear();
 168
 169                 audio_streams_ = std::move(next_audio_streams);
 170
 171                 if(audio_streams_.empty())
 172                         audio_streams_[nullptr].audio_data = audio_buffer_ps(audio_cadence_.front(), 0.0f);
 173
 174                 std::vector<float> result_ps(audio_cadence_.front(), 0.0f);
 175                 BOOST_FOREACH(auto& stream, audio_streams_ | boost::adaptors::map_values)
 176                 {
 177                         if(stream.audio_data.size() < result_ps.size())
 178                                 stream.audio_data.resize(result_ps.size(), 0.0f);
 179
 180                         auto out = boost::range::transform(result_ps, stream.audio_data, std::begin(result_ps), std::plus<float>());
 181                         stream.audio_data.erase(std::begin(stream.audio_data), std::begin(stream.audio_data) + std::distance(std::begin(result_ps), out));
 182                 }
 183
 184                 boost::range::rotate(audio_cadence_, std::begin(audio_cadence_)+1);
 185
 186                 audio_buffer result;
 187                 result.reserve(result_ps.size());
 188                 boost::range::transform(result_ps, std::back_inserter(result), [](float sample){return static_cast<int32_t>(sample);});
 189
 190                 return result;
 191         }
 192 };
 193
 194 audio_mixer::audio_mixer() : impl_(new impl()){}
 195 void audio_mixer::push(const frame_transform& transform){impl_->push(transform);}
 196 void audio_mixer::visit(const const_frame& frame){impl_->visit(frame);}
 197 void audio_mixer::pop(){impl_->pop();}
 198 audio_buffer audio_mixer::operator()(const video_format_desc& format_desc){return impl_->mix(format_desc);}
 199
 200 }}