ExportPluginHelpers.cpp

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/**********************************************************************
 
  Audacity: A Digital Audio Editor
 
  ExportPluginHelpers.cpp
 
  Dominic Mazzoni
 
  Vitaly Sverchinsky split from ExportPlugin.h
 
**********************************************************************/
 
#include "ExportPluginHelpers.h"
#include "Track.h"
#include "Mix.h"
#include "WaveTrack.h"
#include "MixAndRender.h"
#include "ExportUtils.h"
#include "ExportPlugin.h"
#include "StretchingSequence.h"
 
//Create a mixer by computing the time warp factor
std::unique_ptr<Mixer> ExportPluginHelpers::CreateMixer(
   const AudacityProject& project, bool selectionOnly, double startTime,
   double stopTime, unsigned numOutChannels, size_t outBufferSize,
   bool outInterleaved, double outRate, sampleFormat outFormat,
   MixerOptions::Downmix* mixerSpec)
{
   Mixer::Inputs inputs;
   const auto& tracks = TrackList::Get(project);
   for (auto pTrack: ExportUtils::FindExportWaveTracks(tracks, selectionOnly))
      inputs.emplace_back(
         StretchingSequence::Create(*pTrack, pTrack->GetClipInterfaces()),
         GetEffectStages(*pTrack));
   auto masterEffectStages = GetMasterEffectStages(project);
   //custom channel mapping isn't support with master effects on
   assert(masterEffectStages.empty() || (numOutChannels <= 2 && mixerSpec == nullptr));
   // MB: the stop time should not be warped, this was a bug.
   return std::make_unique<Mixer>(
      std::move(inputs), std::move(masterEffectStages),
      // Throw, to stop exporting, if read fails:
      true, Mixer::WarpOptions { tracks.GetOwner() }, startTime, stopTime,
      numOutChannels, outBufferSize, outInterleaved, outRate, outFormat, true,
      mixerSpec,
      mixerSpec ? Mixer::ApplyVolume::MapChannels : Mixer::ApplyVolume::Mixdown);
}
 
namespace
{
   double EvalExportProgress(Mixer &mixer, double t0, double t1)
   {
      const auto duration = t1 - t0;
      if(duration > 0)
         return std::clamp(mixer.MixGetCurrentTime() - t0, .0, duration) / duration;
      return .0;
   }
}
 
ExportResult ExportPluginHelpers::UpdateProgress(ExportProcessorDelegate& delegate, Mixer &mixer, double t0, double t1)
{
   delegate.OnProgress(EvalExportProgress(mixer, t0, t1));
   if(delegate.IsStopped())
      return ExportResult::Stopped;
   if(delegate.IsCancelled())
      return ExportResult::Cancelled;
   return ExportResult::Success;
}