git.sesse.net Git - casparcg/blob - modules/ffmpeg/producer/audio/audio_decoder.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_decoder.h"\r
  23 \r
  24 #if defined(_MSC_VER)\r
  25 #pragma warning (push)\r
  26 #pragma warning (disable : 4244)\r
  27 #endif\r
  28 extern "C" \r
  29 {\r
  30         #define __STDC_CONSTANT_MACROS\r
  31         #define __STDC_LIMIT_MACROS\r
  32         #include <libavformat/avformat.h>\r
  33         #include <libavcodec/avcodec.h>\r
  34 }\r
  35 #if defined(_MSC_VER)\r
  36 #pragma warning (pop)\r
  37 #endif\r
  38 \r
  39 namespace caspar {\r
  40 \r
  41 struct audio_decoder::implementation : boost::noncopyable\r
  42 {\r
  43         typedef std::vector<short, tbb::cache_aligned_allocator<short>> buffer;\r
  44         \r
  45         AVCodecContext* codec_context_;\r
  46 \r
  47         buffer audio_buffer_;   \r
  48         buffer current_chunk_;\r
  49 \r
  50         const size_t audio_frame_size_;\r
  51 \r
  52         static const size_t SAMPLE_RATE = 48000;\r
  53         static const size_t N_CHANNELS = 2;\r
  54 \r
  55 public:\r
  56         explicit implementation(AVCodecContext* codec_context, double fps) \r
  57                 : codec_context_(codec_context)\r
  58                 , audio_buffer_(4*SAMPLE_RATE*2+FF_INPUT_BUFFER_PADDING_SIZE/2)\r
  59                 , audio_frame_size_(static_cast<size_t>(static_cast<double>(SAMPLE_RATE) / fps) * N_CHANNELS)\r
  60         {\r
  61                 if(!codec_context)\r
  62                         BOOST_THROW_EXCEPTION(null_argument() << arg_name_info("codec_context"));                                               \r
  63         }\r
  64                 \r
  65         std::vector<std::vector<short>> execute(const std::shared_ptr<aligned_buffer>& audio_packet)\r
  66         {                               \r
  67                 if(!audio_packet)\r
  68                         return std::vector<std::vector<short>>();\r
  69 \r
  70                 if(audio_packet->empty()) // Need to flush\r
  71                 {\r
  72                         avcodec_flush_buffers(codec_context_);\r
  73                         return std::vector<std::vector<short>>();\r
  74                 }\r
  75 \r
  76                 int written_bytes = audio_buffer_.size()*2 - FF_INPUT_BUFFER_PADDING_SIZE;\r
  77                 const int errn = avcodec_decode_audio2(codec_context_, audio_buffer_.data(), &written_bytes, audio_packet->data(), audio_packet->size());\r
  78 \r
  79                 if(errn < 0 || codec_context_->sample_rate != SAMPLE_RATE || codec_context_->channels != 2)\r
  80                 {       \r
  81                         BOOST_THROW_EXCEPTION(\r
  82                                 invalid_operation() <<\r
  83                                 boost::errinfo_api_function("avcodec_decode_audio2") <<\r
  84                                 boost::errinfo_errno(AVUNERROR(errn)));\r
  85                 }\r
  86 \r
  87                 current_chunk_.insert(current_chunk_.end(), audio_buffer_.data(), audio_buffer_.data() + written_bytes/2);\r
  88 \r
  89                 std::vector<std::vector<short>> chunks;\r
  90                                 \r
  91                 const auto last = current_chunk_.end() - current_chunk_.size() % audio_frame_size_;\r
  92 \r
  93                 for(auto it = current_chunk_.begin(); it != last; it += audio_frame_size_)              \r
  94                         chunks.push_back(std::vector<short>(it, it + audio_frame_size_));               \r
  95 \r
  96                 current_chunk_.erase(current_chunk_.begin(), last);\r
  97                 \r
  98                 return chunks;\r
  99         }\r
 100 };\r
 101 \r
 102 audio_decoder::audio_decoder(AVCodecContext* codec_context, double fps) : impl_(new implementation(codec_context, fps)){}\r
 103 std::vector<std::vector<short>> audio_decoder::execute(const std::shared_ptr<aligned_buffer>& audio_packet){return impl_->execute(audio_packet);}\r
 104 }