src/lib/external_audio_decoder.cc

   1 #include <sndfile.h>
   2 #include "external_audio_decoder.h"
   3 #include "film.h"
   4 #include "exceptions.h"
   5
   6 using std::vector;
   7 using std::string;
   8 using std::min;
   9 using boost::shared_ptr;
  10
  11 ExternalAudioDecoder::ExternalAudioDecoder (shared_ptr<Film> f, shared_ptr<const Options> o, Job* j)
  12         : Decoder (f, o, j)
  13         , AudioDecoder (f, o, j)
  14 {
  15
  16 }
  17
  18 bool
  19 ExternalAudioDecoder::pass ()
  20 {
  21         vector<string> const files = _film->external_audio ();
  22
  23         int N = 0;
  24         for (size_t i = 0; i < files.size(); ++i) {
  25                 if (!files[i].empty()) {
  26                         N = i + 1;
  27                 }
  28         }
  29
  30         if (N == 0) {
  31                 return true;
  32         }
  33
  34         bool first = true;
  35         sf_count_t frames = 0;
  36
  37         vector<SNDFILE*> sndfiles;
  38         for (vector<string>::const_iterator i = files.begin(); i != files.end(); ++i) {
  39                 if (i->empty ()) {
  40                         sndfiles.push_back (0);
  41                 } else {
  42                         SF_INFO info;
  43                         SNDFILE* s = sf_open (i->c_str(), SFM_READ, &info);
  44                         if (!s) {
  45                                 throw DecodeError ("could not open external audio file for reading");
  46                         }
  47
  48                         if (info.channels != 1) {
  49                                 throw DecodeError ("external audio files must be mono");
  50                         }
  51
  52                         sndfiles.push_back (s);
  53
  54                         if (first) {
  55                                 /* XXX: nasty magic value */
  56                                 AudioStream st ("DVDOMATIC-EXTERNAL", -1, info.samplerate, av_get_default_channel_layout (info.channels));
  57                                 _audio_streams.push_back (st);
  58                                 _audio_stream = st;
  59                                 frames = info.frames;
  60                                 first = false;
  61                         } else {
  62                                 if (info.frames != frames) {
  63                                         throw DecodeError ("external audio files have differing lengths");
  64                                 }
  65                         }
  66                 }
  67         }
  68
  69         sf_count_t const block = 65536;
  70
  71         shared_ptr<AudioBuffers> audio (new AudioBuffers (_audio_stream.get().channels(), block));
  72         while (frames > 0) {
  73                 sf_count_t const this_time = min (block, frames);
  74                 for (size_t i = 0; i < sndfiles.size(); ++i) {
  75                         if (!sndfiles[i]) {
  76                                 audio->make_silent (i);
  77                         } else {
  78                                 sf_read_float (sndfiles[i], audio->data(i), block);
  79                         }
  80                 }
  81
  82                 Audio (audio);
  83                 frames -= this_time;
  84         }
  85
  86         return true;
  87 }