Method Import

modules/import-export/mod-ffmpeg/ImportFFmpeg.cpp:451–551

}

void FFmpegImportFileHandle::Import(
   ImportProgressListener& progressListener, WaveTrackFactory* trackFactory,
   TrackHolders& outTracks, Tags* tags,
   std::optional<LibFileFormats::AcidizerTags>&)
{
   outTracks.clear();
   mCancelled = false;
   mStopped = false;

   //! This may break the correspondence with mStreamInfo
   mStreamContexts.erase (std::remove_if (mStreamContexts.begin (), mStreamContexts.end (), [](const StreamContext& ctx) {
      return !ctx.Use;
   }), mStreamContexts.end());

   for(unsigned s = 0; s < mStreamContexts.size(); ++s)
   {
      const StreamContext& sc = mStreamContexts[s];

      const auto format = ImportUtils::ChooseFormat(sc.SampleFormat);
      auto tracks = trackFactory->CreateMany(sc.InitialChannels, format, sc.CodecContext->GetSampleRate());


      // Handles the start_time by creating silence. This may or may not be correct.
      // There is a possibility that we should ignore first N milliseconds of audio instead. I do not know.
      /// TODO: Nag FFmpeg devs about start_time until they finally say WHAT is this and HOW to handle it.

      int64_t stream_delay = 0;

      const int64_t streamStartTime =
         mAVFormatContext->GetStream(sc.StreamIndex)->GetStartTime();

      if (streamStartTime != int64_t(AUDACITY_AV_NOPTS_VALUE) && streamStartTime > 0)
      {
         stream_delay = streamStartTime;

         wxLogDebug(
            wxT("Stream %d start_time = %lld, that would be %f milliseconds."),
            s, (long long)streamStartTime, double(streamStartTime) / 1000);
      }
      if (stream_delay > 0)
      {
         for (auto track : *tracks)
         {
            track->InsertSilence(0, double(stream_delay) / AUDACITY_AV_TIME_BASE);
         }
      }

      mStreams.push_back(tracks);
   }

   // This is the heart of the importing process

   // Read frames.
   for (std::unique_ptr<AVPacketWrapper> packet;
        (packet = mAVFormatContext->ReadNextPacket()) != nullptr &&
        !mCancelled && !mStopped;)
   {
      // Find a matching StreamContext