/**********************************************************************

   Audacity: A Digital Audio Editor

   ExportFFmpeg.cpp

   Audacity(R) is copyright (c) 1999-2009 Audacity Team.
   License: GPL v2 or later.  See License.txt.

   LRN

******************************************************************//**

\class ExportFFmpeg
\brief Controlling class for FFmpeg exporting.  Creates the options
dialog of the appropriate type, adds tags and invokes the export
function.

*//*******************************************************************/


#include "../FFmpeg.h"
#include "FFmpegFunctions.h"
#include "FifoBuffer.h"

#include <wx/app.h>
#include <wx/log.h>

#include <wx/window.h>
#include <wx/button.h>
#include <wx/textctrl.h>

#include "BasicSettings.h"
#include "Mix.h"
#include "Tags.h"
#include "Track.h"
#include "wxFileNameWrapper.h"

#include "ExportFFmpegOptions.h"
#include "SelectFile.h"
#include "ShuttleGui.h"

#include "ExportPluginHelpers.h"
#include "PlainExportOptionsEditor.h"
#include "FFmpegDefines.h"
#include "ExportOptionsUIServices.h"
#include "ExportPluginRegistry.h"

#if defined(WIN32) && _MSC_VER < 1900
#define snprintf _snprintf
#endif

// Define this to automatically resample audio to the nearest supported sample rate
#define FFMPEG_AUTO_RESAMPLE 1

static int AdjustFormatIndex(int format)
{
   int subFormat = -1;
   for (int i = 0; i <= FMT_OTHER; i++)
   {
      if (ExportFFmpegOptions::fmts[i].compiledIn) subFormat++;
      if (subFormat == format || i == FMT_OTHER)
      {
         subFormat = i;
         break;
      }
   }
   return subFormat;
}

namespace
{

const int iAC3SampleRates[] =
{ 32000, 44100, 48000, 0 };

const int iWMASampleRates[] =
{ 8000, 11025, 16000, 22050, 44100, 0};

///\param rates 0-terminated array
ExportOptionsEditor::SampleRateList ToSampleRateList(const int* rates)
{
   ExportOptionsEditor::SampleRateList list;
   int index = 0;
   while(rates[index] != 0)
      list.push_back(rates[index++]);
   return list;
}

// i18n-hint kbps abbreviates "thousands of bits per second"
TranslatableString n_kbps(int n) { return XO("%d kbps").Format( n ); }
TranslatableString f_kbps( double d ) { return XO("%.2f kbps").Format( d ); }

enum : int
{
   AC3OptionIDBitRate = 0
};

const std::initializer_list<PlainExportOptionsEditor::OptionDesc> AC3Options {
   {
      {
         AC3OptionIDBitRate, XO("Bit Rate"),
         160000,
         ExportOption::TypeEnum,
         {
            32000,
            40000,
            48000,
            56000,
            64000,
            80000,
            96000,
            112000,
            128000,
            160000,
            192000,
            224000,
            256000,
            320000,
            384000,
            448000,
            512000,
            576000,
            640000
         },
         {
            n_kbps( 32 ),
            n_kbps( 40 ),
            n_kbps( 48 ),
            n_kbps( 56 ),
            n_kbps( 64 ),
            n_kbps( 80 ),
            n_kbps( 96 ),
            n_kbps( 112 ),
            n_kbps( 128 ),
            n_kbps( 160 ),
            n_kbps( 192 ),
            n_kbps( 224 ),
            n_kbps( 256 ),
            n_kbps( 320 ),
            n_kbps( 384 ),
            n_kbps( 448 ),
            n_kbps( 512 ),
            n_kbps( 576 ),
            n_kbps( 640 ),
         }
      }, wxT("/FileFormats/AC3BitRate")
   }
};

enum : int
{
   AACOptionIDQuality = 0
};

//NB: user-entered values for AAC are not always followed; mono is clamped to 98-160, stereo 196-320
const std::initializer_list<PlainExportOptionsEditor::OptionDesc> AACOptions {
   {
      {
         AACOptionIDQuality, XO("Quality (kbps)"),
         256,
         ExportOption::TypeRange,
         {98, 320}
      }, wxT("/FileFormats/AACQuality")
   }
};

enum : int
{
   AMRNBOptionIDBitRate = 0
};

const std::initializer_list<PlainExportOptionsEditor::OptionDesc> AMRNBOptions {
   {
      {
         AMRNBOptionIDBitRate, XO("Bit Rate"),
         12200,
         ExportOption::TypeEnum,
         {
            4750,
            5150,
            5900,
            6700,
            7400,
            7950,
            10200,
            12200,
         },
         {
            f_kbps( 4.75 ),
            f_kbps( 5.15 ),
            f_kbps( 5.90 ),
            f_kbps( 6.70 ),
            f_kbps( 7.40 ),
            f_kbps( 7.95 ),
            f_kbps( 10.20 ),
            f_kbps( 12.20 ),
         }
      }, wxT("/FileFormats/AMRNBBitRate")
   }
};

#ifdef SHOW_FFMPEG_OPUS_EXPORT
enum : int
{
   OPUSOptionIDBitRate = 0,
   OPUSOptionIDCompression,
   OPUSOptionIDFrameDuration,
   OPUSOptionIDVBRMode,
   OPUSOptionIDApplication,
   OPUSOptionIDCutoff
};

const std::initializer_list<PlainExportOptionsEditor::OptionDesc> OPUSOptions {
   {
      {
         OPUSOptionIDBitRate, XO("Bit Rate"),
         128000,
         ExportOption::TypeEnum,
         {
            6000,
            8000,
            16000,
            24000,
            32000,
            40000,
            48000,
            64000,
            80000,
            96000,
            128000,
            160000,
            192000,
            256000
         },
         {
            n_kbps( 6 ),
            n_kbps( 8 ),
            n_kbps( 16 ),
            n_kbps( 24 ),
            n_kbps( 32 ),
            n_kbps( 40 ),
            n_kbps( 48 ),
            n_kbps( 64 ),
            n_kbps( 80 ),
            n_kbps( 96 ),
            n_kbps( 128 ),
            n_kbps( 160 ),
            n_kbps( 192 ),
            n_kbps( 256 ),
         }
      }, wxT("/FileFormats/OPUSBitrate")
   },
   {
      {
         OPUSOptionIDCompression, XO("Compression"),
         10,
         ExportOption::TypeRange,
         { 0, 10 }
      }, wxT("/FileFormats/OPUSCompression")
   },
   {
      {
         OPUSOptionIDFrameDuration, XO("Frame Duration"),
         std::string("20"),
         ExportOption::TypeEnum,
         {
            std::string("2.5"),
            std::string("5"),
            std::string("10"),
            std::string("20"),
            std::string("40"),
            std::string("60")
         },
         {
            XO("2.5 ms"),
            XO("5 ms"),
            XO("10 ms"),
            XO("20 ms"),
            XO("40 ms"),
            XO("60 ms"),
         }
      }, wxT("/FileFormats/OPUSFrameDuration")
   },
   {
      {
         OPUSOptionIDVBRMode, XO("Vbr Mode"),
         std::string("on"),
         ExportOption::TypeEnum,
         { std::string("off"), std::string("on"), std::string("constrained") },
         { XO("Off"), XO("On"), XO("Constrained") }
      }, wxT("/FileFormats/OPUSVbrMode")
   },
   {
      {
         OPUSOptionIDApplication, XO("Application"),
         std::string("audio"),
         ExportOption::TypeEnum,
         { std::string("voip"), std::string("audio"), std::string("lowdelay") },
         { XO("VOIP"), XO("Audio"), XO("Low Delay") }
      }, wxT("/FileFormats/OPUSApplication")
   },
   {
      {
         OPUSOptionIDCutoff, XO("Cutoff"),
         std::string("0"),
         ExportOption::TypeEnum,
         {
            std::string("0"),
            std::string("4000"),
            std::string("6000"),
            std::string("8000"),
            std::string("12000"),
            std::string("20000")
         },
         {
            XO("Disabled"),
            XO("Narrowband"),
            XO("Mediumband"),
            XO("Wideband"),
            XO("Super Wideband"),
            XO("Fullband")
         }
      }, wxT("/FileFormats/OPUSCutoff")
   },
};
#endif

enum : int
{
   WMAOptionIDBitRate = 0
};

const std::initializer_list<PlainExportOptionsEditor::OptionDesc> WMAOptions {
   {
      {
         WMAOptionIDBitRate, XO("Bit Rate"),
         128000,
         ExportOption::TypeEnum,
         {
            24000,
            32000,
            40000,
            48000,
            64000,
            80000,
            96000,
            128000,
            160000,
            192000,
            256000,
            320000
         },
         {
            n_kbps(24),
            n_kbps(32),
            n_kbps(40),
            n_kbps(48),
            n_kbps(64),
            n_kbps(80),
            n_kbps(96),
            n_kbps(128),
            n_kbps(160),
            n_kbps(192),
            n_kbps(256),
            n_kbps(320),
         }
      }, wxT("/FileFormats/WMABitRate")
   }
};

const std::vector<ExportOption> FFmpegOptions {
   { FELanguageID, {}, std::string() },
   { FESampleRateID, {}, 0 },
   { FEBitrateID, {}, 0 },
   { FETagID, {}, std::string() },
   { FEQualityID, {}, 0 },
   { FECutoffID, {}, 0},
   { FEBitReservoirID, {}, true },
   { FEVariableBlockLenID, {}, true },
   { FECompLevelID, {}, -1 },
   { FEFrameSizeID, {}, 0 },
   { FELPCCoeffsID, {}, 0 },
   { FEMinPredID, {}, -1 },
   { FEMaxPredID, {}, -1 },
   { FEMinPartOrderID, {}, -1 },
   { FEMaxPartOrderID, {}, -1 },
   { FEPredOrderID, {}, 0 },
   { FEMuxRateID, {}, 0 },
   { FEPacketSizeID, {}, 0 },
   { FECodecID, {}, std::string() },
   { FEFormatID, {}, std::string() }
};

class ExportOptionsFFmpegCustomEditor
   : public ExportOptionsEditor
   , public ExportOptionsUIServices
{
   std::unordered_map<int, ExportValue> mValues;
   std::shared_ptr<FFmpegFunctions> mFFmpeg;
   ExportOptionsEditor::Listener* mListener{};
   //created on-demand
   mutable std::unique_ptr<AVCodecWrapper> mAVCodec;
public:

   ExportOptionsFFmpegCustomEditor(ExportOptionsEditor::Listener* listener = nullptr)
      : mListener(listener)
   {
   }

   void PopulateUI(ShuttleGui& S) override
   {
      CheckFFmpeg(true);
      //Continue anyway, as we do not need ffmpeg functions to build and fill in the UI

      mParent = S.GetParent();

      S.StartHorizontalLay(wxCENTER);
      {
         S.StartVerticalLay(wxCENTER, 0);
         {
            S.AddButton(XXO("Open custom FFmpeg format options"))
               ->Bind(wxEVT_BUTTON, &ExportOptionsFFmpegCustomEditor::OnOpen, this);
            S.StartMultiColumn(2, wxCENTER);
            {
               S.AddPrompt(XXO("Current Format:"));
               mFormat = S.Name(XXO("Current Format:"))
                  .Style(wxTE_READONLY).AddTextBox({}, wxT(""), 25);
               S.AddPrompt(XXO("Current Codec:"));
               mCodec = S.Name(XXO("Current Codec:"))
                  .Style(wxTE_READONLY).AddTextBox({}, wxT(""), 25);
            }
            S.EndMultiColumn();
         }
         S.EndHorizontalLay();
      }
      S.EndHorizontalLay();

      UpdateCodecAndFormat();
   }

   bool TransferDataFromWindow() override
   {
      Load(*gPrefs);
      return true;
   }

   int GetOptionsCount() const override
   {
      return static_cast<int>(FFmpegOptions.size());
   }

   bool GetOption(int index, ExportOption& option) const override
   {
      if(index >= 0 && index < FFmpegOptions.size())
      {
         option = FFmpegOptions[index];
         return true;
      }
      return false;
   }

   bool GetValue(int id, ExportValue& value) const override
   {
      auto it = mValues.find(id);
      if(it != mValues.end())
      {
         value = it->second;
         return true;
      }
      return false;
   }

   bool SetValue(int id, const ExportValue& value) override
   {
      return false;
   }

   SampleRateList GetSampleRateList() const override
   {
      if(!mAVCodec)
      {
         auto it = mValues.find(FECodecID);
         if(it == mValues.end())
            return {};

         const auto codecId = *std::get_if<std::string>(&it->second);
         if (mFFmpeg) {
            mAVCodec = mFFmpeg->CreateEncoder(codecId.c_str());
         }
      }
      if(!mAVCodec)
         return {};

      if(const auto rates = mAVCodec->GetSupportedSamplerates())
         return ToSampleRateList(rates);
      return {};
   }

   void Load(const audacity::BasicSettings& config) override
   {
      mValues[FELanguageID] = std::string(config.Read(wxT("/FileFormats/FFmpegLanguage"), wxT("")).ToUTF8());
      mValues[FESampleRateID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegSampleRate"), 0L));
      mValues[FEBitrateID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegBitRate"), 0L));
      mValues[FETagID] = std::string(config.Read(wxT("/FileFormats/FFmpegTag"), wxT(""))
            .mb_str(wxConvUTF8));
      mValues[FEQualityID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegQuality"), -99999L));
      mValues[FECutoffID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegCutOff"), 0L));
      mValues[FEBitReservoirID] = config.ReadBool(wxT("/FileFormats/FFmpegBitReservoir"), true);
      mValues[FEVariableBlockLenID] = config.ReadBool(wxT("/FileFormats/FFmpegVariableBlockLen"), true);
      mValues[FECompLevelID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegCompLevel"), -1L));
      mValues[FEFrameSizeID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegFrameSize"), 0L));

      mValues[FELPCCoeffsID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegLPCCoefPrec"), 0L));
      mValues[FEMinPredID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegMinPredOrder"), -1L));
      mValues[FEMaxPredID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegMaxPredOrder"), -1L));
      mValues[FEMinPartOrderID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegMinPartOrder"), -1L));
      mValues[FEMaxPartOrderID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegMaxPartOrder"), -1L));
      mValues[FEPredOrderID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegPredOrderMethod"), 0L));
      mValues[FEMuxRateID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegMuxRate"), 0L));
      mValues[FEPacketSizeID] = static_cast<int>(config.Read(wxT("/FileFormats/FFmpegPacketSize"), 0L));
      mValues[FECodecID] = std::string(config.Read(wxT("/FileFormats/FFmpegCodec")));
      mValues[FEFormatID] = std::string(config.Read(wxT("/FileFormats/FFmpegFormat")));
   }

   void Store(audacity::BasicSettings& settings) const override
   {

   }

private:

   bool CheckFFmpeg(bool showError)
   {
      // Show "Locate FFmpeg" dialog
      if(!mFFmpeg)
      {
         mFFmpeg = FFmpegFunctions::Load();
         if (!mFFmpeg)
         {
            FindFFmpegLibs();
            return LoadFFmpeg(showError);
         }
      }
      return true;
   }

   void UpdateCodecAndFormat()
   {
      mFormat->SetValue(gPrefs->Read(wxT("/FileFormats/FFmpegFormat"), wxT("")));
      mCodec->SetValue(gPrefs->Read(wxT("/FileFormats/FFmpegCodec"), wxT("")));
   }

   void OnOpen(const wxCommandEvent&)
   {
      if(!CheckFFmpeg(true))
         return;

   #ifdef __WXMAC__
      // Bug 2077 Must be a parent window on OSX or we will appear behind.
      auto pWin = wxGetTopLevelParent( mParent );
   #else
      // Use GetTopWindow on windows as there is no hWnd with top level parent.
      auto pWin = wxTheApp->GetTopWindow();
   #endif

      ExportFFmpegOptions od(pWin);
      od.ShowModal();
      //ExportFFmpegOptions uses gPrefs to store options
      //Instead we could provide it with instance of wxConfigBase
      //constructed locally and read from it later
      Load(*gPrefs);
      mAVCodec.reset();

      UpdateCodecAndFormat();
      if(mListener)
         mListener->OnSampleRateListChange();
   }

   wxWindow   *mParent {nullptr};
   wxTextCtrl *mFormat {nullptr};
   wxTextCtrl *mCodec {nullptr};
};

}

///Performs actual export
class FFmpegExporter final
{
   static constexpr auto MaxAudioPacketSize { 128 * 1024 };
public:

   FFmpegExporter(std::shared_ptr<FFmpegFunctions> ffmpeg,
      const wxFileNameWrapper& filename,
      int numChannels,
      int subformat);

   /// Format initialization
   bool Init(const char *shortname,
      AudacityProject *project,
      int sampleRate,
      const Tags *metadata,
      const ExportProcessor::Parameters& parameters);

   /// Encodes audio
   bool EncodeAudioFrame(int16_t *pFrame, size_t frameSize);

   /// Flushes audio encoder
   bool Finalize();

   std::unique_ptr<Mixer> CreateMixer(
      const AudacityProject& project, bool selectionOnly, double startTime,
      double stopTime, MixerOptions::Downmix* mixerSpec);

private:

   /// Writes metadata
   bool AddTags(const Tags *metadata);

   /// Sets individual metadata values
   void SetMetadata(const Tags *tags, const char *name, const wxChar *tag);

   /// Check whether or not current project sample rate is compatible with the export codec
   bool CheckSampleRate(int rate, int lowrate, int highrate, const int *sampRates);

   /// Asks user to resample the project or cancel the export procedure
   int AskResample(int bitrate, int rate, int lowrate, int highrate, const int *sampRates);

   /// Codec initialization
   bool InitCodecs(int sampleRate,
      const ExportProcessor::Parameters& parameters);

   void WritePacket(AVPacketWrapper& packet);

   int EncodeAudio(AVPacketWrapper& pkt,
      int16_t* audio_samples,
      int nb_samples);

   std::shared_ptr<FFmpegFunctions> mFFmpeg;

   std::unique_ptr<AVOutputFormatWrapper> mEncFormatDesc;       // describes our output file to libavformat
   int mDefaultFrameSize {};
   std::unique_ptr<AVStreamWrapper> mEncAudioStream; // the output audio stream (may remain NULL)
   int mEncAudioFifoOutBufSize {};

   wxFileNameWrapper mName;

   int               mSubFormat{};
   int               mBitRate{};
   int               mSampleRate{};
   unsigned          mChannels{};
   bool              mSupportsUTF8{true};

   // Smart pointer fields, their order is the reverse in which they are reset in FreeResources():
   std::unique_ptr<FifoBuffer> mEncAudioFifo; // FIFO to write incoming audio samples into
   AVDataBuffer<int16_t> mEncAudioFifoOutBuf; // buffer to read _out_ of the FIFO into
   std::unique_ptr<AVFormatContextWrapper> mEncFormatCtx; // libavformat's context for our output file
   std::unique_ptr<AVCodecContextWrapper> mEncAudioCodecCtx;    // the encoder for the output audio stream
};

class FFmpegExportProcessor final : public ExportProcessor
{
   std::shared_ptr<FFmpegFunctions> mFFmpeg;
   struct
   {
      //same index as in GetFormatInfo, use AdjustFormatIndex to convert it to FFmpegExposedFormat
      int subformat;
      TranslatableString status;
      double t0;
      double t1;
      std::unique_ptr<Mixer> mixer;
      std::unique_ptr<FFmpegExporter> exporter;
   } context;

public:
   FFmpegExportProcessor(std::shared_ptr<FFmpegFunctions> ffmpeg, int format);

   bool Initialize(AudacityProject& project,
      const Parameters& parameters,
      const wxFileNameWrapper& filename,
      double t0, double t1, bool selectedOnly,
      double sampleRate, unsigned channels,
      MixerOptions::Downmix* mixerSpec,
      const Tags* tags) override;

   ExportResult Process(ExportProcessorDelegate& delegate) override;

};

class ExportFFmpeg final : public ExportPlugin
{
public:

   ExportFFmpeg();
   ~ExportFFmpeg() override;

   std::unique_ptr<ExportOptionsEditor>
   CreateOptionsEditor(int format, ExportOptionsEditor::Listener* listener) const override;

   int GetFormatCount() const override;
   FormatInfo GetFormatInfo(int index) const override;

   /// Callback, called from GetFilename
   bool CheckFileName(wxFileName &filename, int format = 0) const override;

   std::unique_ptr<ExportProcessor> CreateProcessor(int format) const override;

private:
   mutable std::shared_ptr<FFmpegFunctions> mFFmpeg;

   std::vector<FormatInfo> mFormatInfos;
};

FFmpegExporter::FFmpegExporter(std::shared_ptr<FFmpegFunctions> ffmpeg,
   const wxFileNameWrapper& filename,
   int numChannels,
   int subFormat)
   : mFFmpeg(std::move(ffmpeg))
   , mName(filename)
   , mChannels(numChannels)
   , mSubFormat(subFormat)
{
   if (!mFFmpeg) {
      mFFmpeg = FFmpegFunctions::Load();
   }
}

std::unique_ptr<Mixer> FFmpegExporter::CreateMixer(
   const AudacityProject& project, bool selectionOnly, double startTime,
   double stopTime, MixerOptions::Downmix* mixerSpec)
{
   return ExportPluginHelpers::CreateMixer(
      project, selectionOnly, startTime, stopTime, mChannels, mDefaultFrameSize,
      true, mSampleRate, int16Sample, mixerSpec);
}


ExportFFmpeg::ExportFFmpeg()
{
   mFFmpeg = FFmpegFunctions::Load();

   int avfver = mFFmpeg ? mFFmpeg->AVFormatVersion.GetIntVersion() : 0;

   int newfmt;
   // Adds export types from the export type list
   for (newfmt = 0; newfmt < FMT_LAST; newfmt++)
   {
      wxString shortname(ExportFFmpegOptions::fmts[newfmt].shortname);
      // Don't hide export types when there's no av-libs, and don't hide FMT_OTHER
      if (newfmt < FMT_OTHER && mFFmpeg)
      {
         // Format/Codec support is compiled in?
         auto avoformat = mFFmpeg->GuessOutputFormat(shortname.mb_str(), nullptr, nullptr);
         auto avcodec = mFFmpeg->CreateEncoder(mFFmpeg->GetAVCodecID(ExportFFmpegOptions::fmts[newfmt].codecid));

         if (avoformat == NULL || avcodec == NULL)
         {
            ExportFFmpegOptions::fmts[newfmt].compiledIn = false;
            continue;
         }
      }
      FormatInfo formatInfo {};
      formatInfo.format = ExportFFmpegOptions::fmts[newfmt].name;
      formatInfo.extensions.push_back(ExportFFmpegOptions::fmts[newfmt].extension);
      // For some types add other extensions
      switch(newfmt)
      {
      case FMT_M4A:
         formatInfo.extensions.push_back(wxT("3gp"));
         formatInfo.extensions.push_back(wxT("m4r"));
         formatInfo.extensions.push_back(wxT("mp4"));
         break;
      case FMT_WMA2:
         formatInfo.extensions.push_back(wxT("asf"));
         formatInfo.extensions.push_back(wxT("wmv"));
         break;
      default:
         break;
      }
      formatInfo.maxChannels = ExportFFmpegOptions::fmts[newfmt].maxchannels;
      formatInfo.description = ExportFFmpegOptions::fmts[newfmt].description;

      const int canmeta = ExportFFmpegOptions::fmts[newfmt].canmetadata;
      formatInfo.canMetaData = canmeta && (canmeta == AV_CANMETA || canmeta <= avfver);

      mFormatInfos.push_back(std::move(formatInfo));
   }
}

ExportFFmpeg::~ExportFFmpeg() = default;

std::unique_ptr<ExportOptionsEditor>
ExportFFmpeg::CreateOptionsEditor(int format, ExportOptionsEditor::Listener* listener) const
{
   switch(AdjustFormatIndex(format))
   {
   case FMT_M4A:
      return std::make_unique<PlainExportOptionsEditor>(AACOptions, listener);
   case FMT_AC3:
      return std::make_unique<PlainExportOptionsEditor>(
         AC3Options,
         ToSampleRateList(iAC3SampleRates),
         listener);
   case FMT_AMRNB:
      return std::make_unique<PlainExportOptionsEditor>(
         AMRNBOptions,
         ExportOptionsEditor::SampleRateList {8000},
         listener);
#ifdef SHOW_FFMPEG_OPUS_EXPORT
   case FMT_OPUS:
      return std::make_unique<PlainExportOptionsEditor>(OPUSOptions, listener);
#endif
   case FMT_WMA2:
      return std::make_unique<PlainExportOptionsEditor>(
         WMAOptions,
         ToSampleRateList(iWMASampleRates),
         listener);
   case FMT_OTHER:
      return std::make_unique<ExportOptionsFFmpegCustomEditor>(listener);
   }
   return {};
}

int ExportFFmpeg::GetFormatCount() const
{
   return static_cast<int>(mFormatInfos.size());
}

FormatInfo ExportFFmpeg::GetFormatInfo(int index) const
{
   if(index >= 0 && index < mFormatInfos.size())
      return mFormatInfos[index];
   return mFormatInfos[FMT_OTHER];
}

bool ExportFFmpeg::CheckFileName(wxFileName & WXUNUSED(filename), int WXUNUSED(format)) const
{
   bool result = true;

   // Show "Locate FFmpeg" dialog
   mFFmpeg = FFmpegFunctions::Load();
   if (!mFFmpeg)
   {
      FindFFmpegLibs();
      mFFmpeg = FFmpegFunctions::Load();

      return LoadFFmpeg(true);
   }

   return result;
}

std::unique_ptr<ExportProcessor> ExportFFmpeg::CreateProcessor(int format) const
{
   return std::make_unique<FFmpegExportProcessor>(mFFmpeg, format);
}


bool FFmpegExporter::Init(const char *shortname,
                        AudacityProject *project,
                        int sampleRate,
                        const Tags *metadata,
                        const ExportProcessor::Parameters& parameters)
{
   if (!mFFmpeg)
      return false;

   // See if libavformat has modules that can write our output format. If so, mEncFormatDesc
   // will describe the functions used to write the format (used internally by libavformat)
   // and the default video/audio codecs that the format uses.
   const auto path = mName.GetFullPath();
   if ((mEncFormatDesc = mFFmpeg->GuessOutputFormat(shortname, OSINPUT(path), nullptr)) == nullptr)
   {
      throw ExportException(_("FFmpeg : ERROR - Can't determine format description for file \"%s\".").Format(path));
   }

   // mEncFormatCtx is used by libavformat to carry around context data re our output file.
   mEncFormatCtx = mFFmpeg->CreateAVFormatContext();
   if (!mEncFormatCtx)
   {
      throw ExportException(_("FFmpeg : ERROR - Can't allocate output format context."));
   }

   // Initialise the output format context.
   mEncFormatCtx->SetOutputFormat(mFFmpeg->CreateAVOutputFormatWrapper(mEncFormatDesc->GetWrappedValue()));
   mEncFormatCtx->SetFilename(OSINPUT(path));

   // At the moment Audacity can export only one audio stream
   if ((mEncAudioStream = mEncFormatCtx->CreateStream()) == nullptr)
   {
      throw ExportException(_("FFmpeg : ERROR - Can't add audio stream to output file \"%s\"."));
   }

   // Documentation for avformat_new_stream says
   // "User is required to call avcodec_close() and avformat_free_context() to clean
   // up the allocation by avformat_new_stream()."

   // We use smart pointers that ensure these cleanups either in their destructors or
   // sooner if they are reset.  These are std::unique_ptr with nondefault deleter
   // template parameters.

   // mEncFormatCtx takes care of avformat_free_context(), so
   // mEncAudioStream can be a plain pointer.

   // mEncAudioCodecCtx now becomes responsible for closing the codec:
   mEncAudioCodecCtx = mEncAudioStream->GetAVCodecContext();
   mEncAudioStream->SetId(0);

   // Open the output file.
   if (!(mEncFormatDesc->GetFlags() & AUDACITY_AVFMT_NOFILE))
   {
      AVIOContextWrapper::OpenResult result =
         mEncFormatCtx->OpenOutputContext(path);

      if (result != AVIOContextWrapper::OpenResult::Success)
      {
         throw ExportException(_("FFmpeg : ERROR - Can't open output file \"%s\" to write. Error code is %d.")
            .Format(path, static_cast<int>(result)));
      }
   }

   // Open the audio stream's codec and initialise any stream related data.
   if(!InitCodecs(sampleRate, parameters))
      return false;

   if (mEncAudioStream->SetParametersFromContext(*mEncAudioCodecCtx) < 0)
      return false;

   if (metadata == NULL)
      metadata = &Tags::Get( *project );

   // Add metadata BEFORE writing the header.
   // At the moment that works with ffmpeg-git and ffmpeg-0.5 for MP4.
   const auto canmeta = ExportFFmpegOptions::fmts[mSubFormat].canmetadata;
   const auto avfver = mFFmpeg->AVFormatVersion.GetIntVersion();
   if (canmeta && (canmeta == AV_CANMETA || canmeta <= avfver))
   {
      mSupportsUTF8 = ExportFFmpegOptions::fmts[mSubFormat].canutf8;
      AddTags(metadata);
   }

   // Write headers to the output file.
   int err =
      mFFmpeg->avformat_write_header(mEncFormatCtx->GetWrappedValue(), nullptr);

   if (err < 0)
   {
      throw ExportException(XO("FFmpeg : ERROR - Can't write headers to output file \"%s\". Error code is %d.")
         .Format( path, err )
         .Translation());
   }

   return true;
}

bool FFmpegExporter::CheckSampleRate(int rate, int lowrate, int highrate, const int *sampRates)
{
   if (lowrate && highrate)
   {
      if (rate < lowrate || rate > highrate)
      {
         return false;
      }
   }

   if (sampRates)
   {
      for (int i = 0; sampRates[i] > 0; i++)
      {
         if (rate == sampRates[i])
         {
            return true;
         }
      }
   }

   return false;
}

bool FFmpegExporter::InitCodecs(int sampleRate,
                                const ExportProcessor::Parameters& parameters)
{
   std::unique_ptr<AVCodecWrapper> codec;

   AVDictionaryWrapper options(*mFFmpeg);

   // Get the sample rate from the passed settings if we haven't set it before.
   // Doing this only when not set allows us to carry the sample rate from one
   // iteration of ExportMultiple to the next.  This prevents multiple resampling
   // dialogs in the event the codec can't support the specified rate.
   if (!mSampleRate)
   {
      //TODO: Does not work with export multiple any more...
      mSampleRate = sampleRate;
   }

   // Configure the audio stream's codec context.

   const auto codecID = ExportFFmpegOptions::fmts[mSubFormat].codecid;

   mEncAudioCodecCtx->SetGlobalQuality(-99999); //quality mode is off by default;

   // Each export type has its own settings
   switch (mSubFormat)
   {
   case FMT_M4A:
   {
      int q = ExportPluginHelpers::GetParameterValue(parameters, AACOptionIDQuality, -99999);

      q = wxClip( q, 98 * mChannels, 160 * mChannels );
      // Set bit rate to between 98 kbps and 320 kbps (if two channels)
      mEncAudioCodecCtx->SetBitRate(q * 1000);
      mEncAudioCodecCtx->SetProfile(AUDACITY_FF_PROFILE_AAC_LOW);
      mEncAudioCodecCtx->SetCutoff(0);

      break;
   }
   case FMT_AC3:
      mEncAudioCodecCtx->SetBitRate(ExportPluginHelpers::GetParameterValue(parameters, AC3OptionIDBitRate, 192000));
      if (!CheckSampleRate(
             mSampleRate, iAC3SampleRates[0],
             iAC3SampleRates[2],
             &iAC3SampleRates[0]))
      {
         mSampleRate = AskResample(
            mEncAudioCodecCtx->GetBitRate(), mSampleRate,
            iAC3SampleRates[0],
            iAC3SampleRates[2],
            &iAC3SampleRates[0]);
      }
      break;
   case FMT_AMRNB:
      mSampleRate = 8000;
      mEncAudioCodecCtx->SetBitRate(ExportPluginHelpers::GetParameterValue(parameters, AMRNBOptionIDBitRate, 12200));
      break;
#ifdef SHOW_FFMPEG_OPUS_EXPORT
   case FMT_OPUS:
      options.Set("b", ExportPluginHelpers::GetParameterValue<std::string>(parameters, OPUSOptionIDBitRate, "128000"), 0);
      options.Set("vbr", ExportPluginHelpers::GetParameterValue<std::string>(parameters, OPUSOptionIDVBRMode, "on"), 0);
      options.Set("compression_level", ExportPluginHelpers::GetParameterValue<std::string>(parameters, OPUSOptionIDCompression, "10"), 0);
      options.Set("frame_duration", ExportPluginHelpers::GetParameterValue<std::string>(parameters, OPUSOptionIDFrameDuration, "20"), 0);
      options.Set("application", ExportPluginHelpers::GetParameterValue<std::string>(parameters, OPUSOptionIDApplication, "audio"), 0);
      options.Set("cutoff", ExportPluginHelpers::GetParameterValue<std::string>(parameters, OPUSOptionIDCutoff, "0"), 0);
      options.Set("mapping_family", mChannels <= 2 ? "0" : "255", 0);
      break;
#endif
   case FMT_WMA2:
      mEncAudioCodecCtx->SetBitRate(ExportPluginHelpers::GetParameterValue(parameters, WMAOptionIDBitRate, 198000));
      if (!CheckSampleRate(
             mSampleRate, iWMASampleRates[0],
             iWMASampleRates[4],
             &iWMASampleRates[0]))
      {
         mSampleRate = AskResample(
            mEncAudioCodecCtx->GetBitRate(), mSampleRate,
            iWMASampleRates[0],
            iWMASampleRates[4],
            &iWMASampleRates[0]);
      }
      break;
   case FMT_OTHER:
   {
      AVDictionaryWrapper streamMetadata = mEncAudioStream->GetMetadata();
      streamMetadata.Set(
         "language",
         ExportPluginHelpers::GetParameterValue<std::string>(parameters, FELanguageID), 0);

      mEncAudioStream->SetMetadata(streamMetadata);

      mEncAudioCodecCtx->SetSampleRate(
         ExportPluginHelpers::GetParameterValue(parameters, FESampleRateID, 0));

      if (mEncAudioCodecCtx->GetSampleRate() != 0)
         mSampleRate = mEncAudioCodecCtx->GetSampleRate();

      mEncAudioCodecCtx->SetBitRate(
         ExportPluginHelpers::GetParameterValue(parameters, FEBitrateID, 0));

      mEncAudioCodecCtx->SetCodecTagFourCC(
         ExportPluginHelpers::GetParameterValue<std::string>(parameters, FETagID).c_str());

      mEncAudioCodecCtx->SetGlobalQuality(
         ExportPluginHelpers::GetParameterValue(parameters, FEQualityID, -99999));
      mEncAudioCodecCtx->SetCutoff(
         ExportPluginHelpers::GetParameterValue(parameters, FECutoffID, 0));
      mEncAudioCodecCtx->SetFlags2(0);

      if (ExportPluginHelpers::GetParameterValue(parameters, FEBitReservoirID, true))
         options.Set("reservoir", "1", 0);

      if (ExportPluginHelpers::GetParameterValue(parameters, FEVariableBlockLenID, true))
         mEncAudioCodecCtx->SetFlags2(
            mEncAudioCodecCtx->GetFlags2() | 0x0004); // WMA only?

      mEncAudioCodecCtx->SetCompressionLevel(
         ExportPluginHelpers::GetParameterValue(parameters, FECompLevelID, -1));
      mEncAudioCodecCtx->SetFrameSize(
         ExportPluginHelpers::GetParameterValue(parameters, FEFrameSizeID, 0));

      // FIXME The list of supported options for the selected encoder should be
      // extracted instead of a few hardcoded

      options.Set(
         "lpc_coeff_precision",
         ExportPluginHelpers::GetParameterValue(parameters, FELPCCoeffsID, 0));
      options.Set(
         "min_prediction_order",
         ExportPluginHelpers::GetParameterValue(parameters, FEMinPredID, -1));
      options.Set(
         "max_prediction_order",
         ExportPluginHelpers::GetParameterValue(parameters, FEMaxPredID, -1));
      options.Set(
         "min_partition_order",
         ExportPluginHelpers::GetParameterValue(parameters, FEMinPartOrderID, -1));
      options.Set(
         "max_partition_order",
         ExportPluginHelpers::GetParameterValue(parameters, FEMaxPartOrderID, -1));
      options.Set(
         "prediction_order_method",
         ExportPluginHelpers::GetParameterValue(parameters, FEPredOrderID, 0));
      options.Set(
         "muxrate",
         ExportPluginHelpers::GetParameterValue(parameters, FEMuxRateID, 0));

      mEncFormatCtx->SetPacketSize(
         ExportPluginHelpers::GetParameterValue(parameters, FEPacketSizeID, 0));

      codec = mFFmpeg->CreateEncoder(
         ExportPluginHelpers::GetParameterValue<std::string>(parameters, FECodecID).c_str());

      if (!codec)
         codec = mFFmpeg->CreateEncoder(mEncFormatDesc->GetAudioCodec());
   }
      break;
   default:
      return false;
   }

   // This happens if user refused to resample the project
   if (mSampleRate == 0) return false;

   if (mEncAudioCodecCtx->GetGlobalQuality() >= 0)
   {
      mEncAudioCodecCtx->SetFlags(
         mEncAudioCodecCtx->GetFlags() | AUDACITY_AV_CODEC_FLAG_QSCALE);
   }
   else
   {
      mEncAudioCodecCtx->SetGlobalQuality(0);
   }

   mEncAudioCodecCtx->SetGlobalQuality(mEncAudioCodecCtx->GetGlobalQuality() * AUDACITY_FF_QP2LAMBDA);
   mEncAudioCodecCtx->SetSampleRate(mSampleRate);
   mEncAudioCodecCtx->SetChannelLayout(mFFmpeg->CreateDefaultChannelLayout(mChannels).get());
   mEncAudioCodecCtx->SetTimeBase({ 1, mSampleRate });
   mEncAudioCodecCtx->SetSampleFmt(static_cast<AVSampleFormatFwd>(AUDACITY_AV_SAMPLE_FMT_S16));
   mEncAudioCodecCtx->SetStrictStdCompliance(
      AUDACITY_FF_COMPLIANCE_EXPERIMENTAL);

   if (codecID == AUDACITY_AV_CODEC_ID_AC3)
   {
      // As of Jan 4, 2011, the default AC3 encoder only accept SAMPLE_FMT_FLT samples.
      // But, currently, Audacity only supports SAMPLE_FMT_S16.  So, for now, look for the
      // "older" AC3 codec.  this is not a proper solution, but will suffice until other
      // encoders no longer support SAMPLE_FMT_S16.
      codec = mFFmpeg->CreateEncoder("ac3_fixed");
   }

   if (!codec)
   {
      codec = mFFmpeg->CreateEncoder(mFFmpeg->GetAVCodecID(codecID));
   }

   // Is the required audio codec compiled into libavcodec?
   if (codec == NULL)
   {
      /* i18n-hint: "codec" is short for a "coder-decoder" algorithm */
      throw ExportException(XO("FFmpeg cannot find audio codec 0x%x.\nSupport for this codec is probably not compiled in.")
                  .Format(static_cast<const unsigned int>(codecID.value))
                  .Translation());
   }

   if (codec->GetSampleFmts()) {
      for (int i = 0; codec->GetSampleFmts()[i] != AUDACITY_AV_SAMPLE_FMT_NONE; i++)
      {
         AVSampleFormatFwd fmt = codec->GetSampleFmts()[i];

         if (
            fmt == AUDACITY_AV_SAMPLE_FMT_U8 ||
            fmt == AUDACITY_AV_SAMPLE_FMT_U8P ||
            fmt == AUDACITY_AV_SAMPLE_FMT_S16 ||
            fmt == AUDACITY_AV_SAMPLE_FMT_S16P ||
            fmt == AUDACITY_AV_SAMPLE_FMT_S32 ||
            fmt == AUDACITY_AV_SAMPLE_FMT_S32P ||
            fmt == AUDACITY_AV_SAMPLE_FMT_FLT ||
            fmt == AUDACITY_AV_SAMPLE_FMT_FLTP)
         {
            mEncAudioCodecCtx->SetSampleFmt(fmt);
         }

         if (
            fmt == AUDACITY_AV_SAMPLE_FMT_S16 ||
            fmt == AUDACITY_AV_SAMPLE_FMT_S16P)
            break;
      }
   }

   if (codec->GetSupportedSamplerates())
   {
      // Workaround for crash in bug #2378.  Proper fix is to get a newer version of FFmpeg.
      if (codec->GetId() == mFFmpeg->GetAVCodecID(AUDACITY_AV_CODEC_ID_AAC))
      {
         std::vector<int> rates;
         int i = 0;

         while (codec->GetSupportedSamplerates()[i] &&
                codec->GetSupportedSamplerates()[i] != 7350)
         {
            rates.push_back(codec->GetSupportedSamplerates()[i++]);
         }

         rates.push_back(0);

         if (!CheckSampleRate(mSampleRate, 0, 0, rates.data()))
         {
            mSampleRate = AskResample(0, mSampleRate, 0, 0, rates.data());
            mEncAudioCodecCtx->SetSampleRate(mSampleRate);
         }
      }
      else
      {
         if (!CheckSampleRate(
                mSampleRate, 0, 0, codec->GetSupportedSamplerates()))
         {
            mSampleRate = AskResample(
               0, mSampleRate, 0, 0, codec->GetSupportedSamplerates());
            mEncAudioCodecCtx->SetSampleRate(mSampleRate);
         }
      }

      // This happens if user refused to resample the project
      if (mSampleRate == 0)
      {
         return false;
      }
   }

   if (mEncFormatCtx->GetOutputFormat()->GetFlags() & AUDACITY_AVFMT_GLOBALHEADER)
   {
      mEncAudioCodecCtx->SetFlags(mEncAudioCodecCtx->GetFlags() | AUDACITY_AV_CODEC_FLAG_GLOBAL_HEADER);
      mEncFormatCtx->SetFlags(mEncFormatCtx->GetFlags() | AUDACITY_AV_CODEC_FLAG_GLOBAL_HEADER);
   }

   // Open the codec.
   int rc = mEncAudioCodecCtx->Open(codec.get(), &options);
   if (rc < 0)
   {
      TranslatableString errmsg;

      switch (rc)
      {
      case AUDACITY_AVERROR(EPERM):
         errmsg = XO("The codec reported a generic error (EPERM)");
         break;
      case AUDACITY_AVERROR(EINVAL):
         errmsg = XO("The codec reported an invalid parameter (EINVAL)");
         break;
      default:
         char buf[64];
         mFFmpeg->av_strerror(rc, buf, sizeof(buf));
         errmsg = Verbatim(buf);
      }

      /* i18n-hint: "codec" is short for a "coder-decoder" algorithm */
      throw ExportException(XO("Can't open audio codec \"%s\" (0x%x)\n\n%s")
         .Format(codec->GetName(), codecID.value, errmsg)
         .Translation());
   }

   mDefaultFrameSize = mEncAudioCodecCtx->GetFrameSize();

   if (mDefaultFrameSize == 0)
      mDefaultFrameSize = 1024; // arbitrary non zero value;

   wxLogDebug(
      wxT("FFmpeg : Audio Output Codec Frame Size: %d samples."),
      mEncAudioCodecCtx->GetFrameSize());

   // The encoder may require a minimum number of raw audio samples for each encoding but we can't
   // guarantee we'll get this minimum each time an audio frame is decoded from the input file so
   // we use a FIFO to store up incoming raw samples until we have enough for one call to the codec.
   mEncAudioFifo = std::make_unique<FifoBuffer>(mDefaultFrameSize * mChannels * sizeof(int16_t));

   mEncAudioFifoOutBufSize = 2*MaxAudioPacketSize;
   // Allocate a buffer to read OUT of the FIFO into. The FIFO maintains its own buffer internally.
   mEncAudioFifoOutBuf = mFFmpeg->CreateMemoryBuffer<int16_t>(mEncAudioFifoOutBufSize);

   if (mEncAudioFifoOutBuf.empty())
   {
      throw ExportException(_("FFmpeg : ERROR - Can't allocate buffer to read into from audio FIFO."));
   }

   return true;
}

void FFmpegExporter::WritePacket(AVPacketWrapper& pkt)
{
   // Set presentation time of frame (currently in the codec's timebase) in the
   // stream timebase.
   if (pkt.GetPresentationTimestamp() != AUDACITY_AV_NOPTS_VALUE)
      pkt.RescalePresentationTimestamp(
         mEncAudioCodecCtx->GetTimeBase(), mEncAudioStream->GetTimeBase());

   if (pkt.GetDecompressionTimestamp() != AUDACITY_AV_NOPTS_VALUE)
      pkt.RescaleDecompressionTimestamp(
         mEncAudioCodecCtx->GetTimeBase(), mEncAudioStream->GetTimeBase());

   if (pkt.GetDuration() > 0)
      pkt.RescaleDuration(
         mEncAudioCodecCtx->GetTimeBase(), mEncAudioStream->GetTimeBase());

   if (
      mFFmpeg->av_interleaved_write_frame(
         mEncFormatCtx->GetWrappedValue(), pkt.GetWrappedValue()) != 0)
   {
      throw ExportException(_("FFmpeg : ERROR - Couldn't write audio frame to output file."));
   }
}

// Returns 0 if no more output, 1 if more output, negative if error
int FFmpegExporter::EncodeAudio(AVPacketWrapper& pkt, int16_t* audio_samples, int nb_samples)
{
   // Assume *pkt is already initialized.

   int i, ch, buffer_size, ret, got_output = 0;
   AVDataBuffer<uint8_t> samples;

   std::unique_ptr<AVFrameWrapper> frame;

   if (audio_samples) {
      frame = mFFmpeg->CreateAVFrameWrapper();

      if (!frame)
         return AUDACITY_AVERROR(ENOMEM);

      frame->SetSamplesCount(nb_samples);
      frame->SetFormat(mEncAudioCodecCtx->GetSampleFmt());
      frame->SetChannelLayout(mEncAudioCodecCtx->GetChannelLayout());

      buffer_size = mFFmpeg->av_samples_get_buffer_size(
         NULL, mEncAudioCodecCtx->GetChannels(), nb_samples,
         mEncAudioCodecCtx->GetSampleFmt(), 0);

      if (buffer_size < 0) {
         throw ExportException(_("FFmpeg : ERROR - Could not get sample buffer size"));
      }

      samples = mFFmpeg->CreateMemoryBuffer<uint8_t>(buffer_size);

      if (samples.empty()) {
         throw ExportException(_("FFmpeg : ERROR - Could not allocate bytes for samples buffer"));
      }
      /* setup the data pointers in the AVFrame */
      ret = mFFmpeg->avcodec_fill_audio_frame(
         frame->GetWrappedValue(), mEncAudioCodecCtx->GetChannels(),
         mEncAudioCodecCtx->GetSampleFmt(), samples.data(), buffer_size, 0);

      if (ret < 0) {
         throw ExportException(_("FFmpeg : ERROR - Could not setup audio frame"));
      }

      const int channelsCount = mEncAudioCodecCtx->GetChannels();

      for (ch = 0; ch < mEncAudioCodecCtx->GetChannels(); ch++)
      {
         for (i = 0; i < nb_samples; i++) {
            switch (static_cast<AudacityAVSampleFormat>(
               mEncAudioCodecCtx->GetSampleFmt()))
            {
            case AUDACITY_AV_SAMPLE_FMT_U8:
               ((uint8_t*)(frame->GetData(0)))[ch + i*channelsCount] = audio_samples[ch + i*channelsCount]/258 + 128;
               break;
            case AUDACITY_AV_SAMPLE_FMT_U8P:
               ((uint8_t*)(frame->GetData(ch)))[i] = audio_samples[ch + i*channelsCount]/258 + 128;
               break;
            case AUDACITY_AV_SAMPLE_FMT_S16:
               ((int16_t*)(frame->GetData(0)))[ch + i*channelsCount] = audio_samples[ch + i*channelsCount];
               break;
            case AUDACITY_AV_SAMPLE_FMT_S16P:
               ((int16_t*)(frame->GetData(ch)))[i] = audio_samples[ch + i*channelsCount];
               break;
            case AUDACITY_AV_SAMPLE_FMT_S32:
               ((int32_t*)(frame->GetData(0)))[ch + i*channelsCount] = audio_samples[ch + i*channelsCount]<<16;
               break;
            case AUDACITY_AV_SAMPLE_FMT_S32P:
               ((int32_t*)(frame->GetData(ch)))[i] = audio_samples[ch + i*channelsCount]<<16;
               break;
            case AUDACITY_AV_SAMPLE_FMT_FLT:
               ((float*)(frame->GetData(0)))[ch + i*channelsCount] = audio_samples[ch + i*channelsCount] / 32767.0;
               break;
            case AUDACITY_AV_SAMPLE_FMT_FLTP:
               ((float*)(frame->GetData(ch)))[i] = audio_samples[ch + i*channelsCount] / 32767.;
               break;
            default:
               wxASSERT(false);
               break;
            }
         }
      }
   }

   pkt.ResetData();

   pkt.SetStreamIndex(mEncAudioStream->GetIndex());

   if (mFFmpeg->avcodec_send_frame != nullptr)
   {
      ret = mFFmpeg->avcodec_send_frame(
         mEncAudioCodecCtx->GetWrappedValue(),
         frame ? frame->GetWrappedValue() : nullptr);

      while (ret >= 0)
      {
         ret = mFFmpeg->avcodec_receive_packet(
            mEncAudioCodecCtx->GetWrappedValue(), pkt.GetWrappedValue());

         if (ret == AUDACITY_AVERROR(EAGAIN) || ret == AUDACITY_AVERROR_EOF)
         {
            ret = 0;
            break;
         }
         else if (ret < 0)
            break;

         WritePacket(pkt);

         got_output = true;
      }
   }
   else
   {
      ret = mFFmpeg->avcodec_encode_audio2(
         mEncAudioCodecCtx->GetWrappedValue(), pkt.GetWrappedValue(),
         frame ? frame->GetWrappedValue() : nullptr, &got_output);

      if (ret == 0)
      {
         WritePacket(pkt);
      }
   }

   if (ret < 0 && ret != AUDACITY_AVERROR_EOF) {

      char buf[64];
      mFFmpeg->av_strerror(ret, buf, sizeof(buf));
      wxLogDebug(buf);

      throw ExportException(_("FFmpeg : ERROR - encoding frame failed"));
   }

   pkt.ResetTimestamps(); // We don't set frame timestamps thus don't trust the AVPacket timestamps

   return got_output;
}


bool FFmpegExporter::Finalize()
{
   // Flush the audio FIFO and encoder.
   for (;;)
   {
      std::unique_ptr<AVPacketWrapper> pkt = mFFmpeg->CreateAVPacketWrapper();

      const auto nFifoBytes =
         mEncAudioFifo->GetAvailable(); // any bytes left in audio FIFO?

      int encodeResult = 0;

      // Flush the audio FIFO first if necessary. It won't contain a _full_ audio frame because
      // if it did we'd have pulled it from the FIFO during the last encodeAudioFrame() call
      if (nFifoBytes > 0)
      {
         const int nAudioFrameSizeOut = mDefaultFrameSize * mEncAudioCodecCtx->GetChannels() * sizeof(int16_t);

         if (nAudioFrameSizeOut > mEncAudioFifoOutBufSize || nFifoBytes > mEncAudioFifoOutBufSize) {
            throw ExportException(_("FFmpeg : ERROR - Too much remaining data."));
         }

         // We have an incomplete buffer of samples left, encode it.
         // If codec supports CODEC_CAP_SMALL_LAST_FRAME, we can feed it with smaller frame
         // Or if frame_size is 1, then it's some kind of PCM codec, they don't have frames and will be fine with the samples
         // Otherwise we'll send a full frame of audio + silence padding to ensure all audio is encoded
         int frame_size = mDefaultFrameSize;
         if (
            mEncAudioCodecCtx->GetCodec()->GetCapabilities() &
               AUDACITY_AV_CODEC_CAP_SMALL_LAST_FRAME ||
            frame_size == 1)
         {
            frame_size = nFifoBytes /
                         (mEncAudioCodecCtx->GetChannels() * sizeof(int16_t));
         }

         wxLogDebug(wxT("FFmpeg : Audio FIFO still contains %lld bytes, writing %d sample frame ..."),
            nFifoBytes, frame_size);

         // Fill audio buffer with zeroes. If codec tries to read the whole buffer,
         // it will just read silence. If not - who cares?
         memset(mEncAudioFifoOutBuf.data(), 0, mEncAudioFifoOutBufSize);
         //const AVCodec *codec = mEncAudioCodecCtx->codec;

         // Pull the bytes out from the FIFO and feed them to the encoder.
         if (mEncAudioFifo->Read(mEncAudioFifoOutBuf.data(), nFifoBytes) == nFifoBytes)
         {
            encodeResult = EncodeAudio(*pkt, mEncAudioFifoOutBuf.data(), frame_size);
         }
         else
         {
            wxLogDebug(wxT("FFmpeg : Reading from Audio FIFO failed, aborting"));
            // TODO: more precise message
            throw ExportErrorException("FFmpeg:825");
         }
      }
      else
      {
         // Fifo is empty, flush encoder. May be called multiple times.
         encodeResult =
            EncodeAudio(*pkt.get(), nullptr, 0);
      }

      if (encodeResult < 0) {
         // TODO: more precise message
         throw ExportErrorException("FFmpeg:837");
      }
      else if (encodeResult == 0)
         break;
   }

   // Write any file trailers.
   if (mFFmpeg->av_write_trailer(mEncFormatCtx->GetWrappedValue()) != 0)
   {
      // TODO: more precise message
      throw ExportErrorException("FFmpeg:868");
   }

   return true;
}

// All paths in this that fail must report their error to the user.
bool FFmpegExporter::EncodeAudioFrame(int16_t *pFrame, size_t numSamples)
{
   const auto frameSize = numSamples * sizeof(int16_t) *  mChannels;
   int nBytesToWrite = 0;
   uint8_t *pRawSamples = nullptr;
   int nAudioFrameSizeOut = mDefaultFrameSize * mEncAudioCodecCtx->GetChannels() * sizeof(int16_t);
   int ret;

   nBytesToWrite = frameSize;
   pRawSamples  = (uint8_t*)pFrame;

   // Put the raw audio samples into the FIFO.
   ret = mEncAudioFifo->Write(pRawSamples, nBytesToWrite);

   if (ret != nBytesToWrite) {
      throw ExportErrorException("FFmpeg:913");
   }

   if (nAudioFrameSizeOut > mEncAudioFifoOutBufSize) {
      throw ExportException(_("FFmpeg : ERROR - nAudioFrameSizeOut too large."));
   }

   // Read raw audio samples out of the FIFO in nAudioFrameSizeOut byte-sized groups to encode.
   while (mEncAudioFifo->GetAvailable() >= nAudioFrameSizeOut)
   {
      mEncAudioFifo->Read(
         mEncAudioFifoOutBuf.data(), nAudioFrameSizeOut);

      std::unique_ptr<AVPacketWrapper> pkt = mFFmpeg->CreateAVPacketWrapper();

      ret = EncodeAudio(*pkt,                       // out
         mEncAudioFifoOutBuf.data(), // in
         mDefaultFrameSize);

      if (ret < 0)
         return false;
   }
   return true;
}

FFmpegExportProcessor::FFmpegExportProcessor(std::shared_ptr<FFmpegFunctions> ffmpeg, int subformat )
   : mFFmpeg(std::move(ffmpeg))
{
   context.subformat = subformat;
}

bool FFmpegExportProcessor::Initialize(AudacityProject& project,
   const Parameters& parameters,
   const wxFileNameWrapper& fName,
   double t0, double t1, bool selectionOnly,
   double sampleRate, unsigned channels,
   MixerOptions::Downmix* mixerSpec,
   const Tags* metadata)
{
   context.t0 = t0;
   context.t1 = t1;

   if (!FFmpegFunctions::Load())
   {
      throw ExportException(_("Properly configured FFmpeg is required to proceed.\nYou can configure it at Preferences > Libraries."));
   }
   // subformat index may not correspond directly to fmts[] index, convert it
   const auto adjustedFormatIndex = AdjustFormatIndex(context.subformat);
   if (channels > ExportFFmpegOptions::fmts[adjustedFormatIndex].maxchannels)
   {
      throw ExportException(XO("Attempted to export %d channels, but maximum number of channels for selected output format is %d")
         .Format(
            channels,
            ExportFFmpegOptions::fmts[adjustedFormatIndex].maxchannels )
         .Translation());
   }

   bool ret = true;

   if (adjustedFormatIndex >= FMT_LAST) {
      // TODO: more precise message
      throw ExportErrorException("FFmpeg:996");
   }

   wxString shortname(ExportFFmpegOptions::fmts[adjustedFormatIndex].shortname);
   if (adjustedFormatIndex == FMT_OTHER)
      shortname = ExportPluginHelpers::GetParameterValue<std::string>(parameters, FEFormatID, "matroska");

   context.exporter = std::make_unique<FFmpegExporter>(mFFmpeg, fName, channels, adjustedFormatIndex);

   ret = context.exporter->Init(shortname.mb_str(), &project, static_cast<int>(sampleRate), metadata, parameters);

   if (!ret) {
      // TODO: more precise message
      throw ExportErrorException("FFmpeg:1008");
   }

   context.mixer =
      context.exporter->CreateMixer(project, selectionOnly, t0, t1, mixerSpec);

   context.status = selectionOnly
         ? XO("Exporting selected audio as %s")
              .Format( ExportFFmpegOptions::fmts[adjustedFormatIndex].description )
         : XO("Exporting the audio as %s")
              .Format( ExportFFmpegOptions::fmts[adjustedFormatIndex].description );

   return true;
}

ExportResult FFmpegExportProcessor::Process(ExportProcessorDelegate& delegate)
{
   delegate.SetStatusString(context.status);
   auto exportResult = ExportResult::Success;
   {
      while (exportResult == ExportResult::Success) {
         auto pcmNumSamples = context.mixer->Process();
         if (pcmNumSamples == 0)
            break;

         short *pcmBuffer = (short *)context.mixer->GetBuffer();

         if (!context.exporter->EncodeAudioFrame(pcmBuffer, pcmNumSamples))
            // All errors should already have been reported.
            return ExportResult::Error;

         if(exportResult == ExportResult::Success)
            exportResult = ExportPluginHelpers::UpdateProgress(
               delegate, *context.mixer, context.t0, context.t1);
      }
   }

   if ( exportResult != ExportResult::Cancelled )
      if ( !context.exporter->Finalize() ) // Finalize makes its own messages
         return ExportResult::Error;
   return exportResult;
}


void AddStringTagUTF8(char field[], int size, wxString value)
{
      memset(field,0,size);
      memcpy(field,value.ToUTF8(),(int)strlen(value.ToUTF8()) > size -1 ? size -1 : strlen(value.ToUTF8()));
}

void AddStringTagANSI(char field[], int size, wxString value)
{
      memset(field,0,size);
      memcpy(field,value.mb_str(),(int)strlen(value.mb_str()) > size -1 ? size -1 : strlen(value.mb_str()));
}

bool FFmpegExporter::AddTags(const Tags *tags)
{
   if (tags == NULL)
   {
      return false;
   }

   SetMetadata(tags, "album", TAG_ALBUM);
   SetMetadata(tags, "comment", TAG_COMMENTS);
   SetMetadata(tags, "genre", TAG_GENRE);
   SetMetadata(tags, "title", TAG_TITLE);
   SetMetadata(tags, "track", TAG_TRACK);

   // Bug 2564: Add m4a tags
   if (mEncFormatDesc->GetAudioCodec() == mFFmpeg->GetAVCodecID(AUDACITY_AV_CODEC_ID_AAC))
   {
      SetMetadata(tags, "artist", TAG_ARTIST);
      SetMetadata(tags, "date", TAG_YEAR);
   }
   else
   {
      SetMetadata(tags, "author", TAG_ARTIST);
      SetMetadata(tags, "year", TAG_YEAR);
   }

   return true;
}

void FFmpegExporter::SetMetadata(const Tags *tags, const char *name, const wxChar *tag)
{
   if (tags->HasTag(tag))
   {
      wxString value = tags->GetTag(tag);

      AVDictionaryWrapper metadata = mEncFormatCtx->GetMetadata();

      metadata.Set(name, mSupportsUTF8 ? value : value.mb_str(), 0);
      mEncFormatCtx->SetMetadata(metadata);
   }
}


//----------------------------------------------------------------------------
// AskResample dialog
//----------------------------------------------------------------------------

int FFmpegExporter::AskResample(int bitrate, int rate, int lowrate, int highrate, const int *sampRates)
{
#if defined(FFMPEG_AUTO_RESAMPLE)
   std::vector<int> rates;

   for (int i = 0; sampRates[i]; ++i)
   {
      rates.push_back(sampRates[i]);
   }

   std::sort(rates.begin(), rates.end());

   int bestRate = 0;
   for (auto i : rates)
   {
      bestRate = i;
      if (i > rate)
      {
         break;
      }
   }

   return bestRate;
#else
   wxDialogWrapper d(nullptr, wxID_ANY, XO("Invalid sample rate"));
   d.SetName();
   wxChoice *choice;
   ShuttleGui S(&d, eIsCreating);

   int selected = -1;

   S.StartVerticalLay();
   {
      S.SetBorder(10);
      S.StartStatic(XO("Resample"));
      {
         S.StartHorizontalLay(wxALIGN_CENTER, false);
         {
            S.AddTitle(
               (bitrate == 0
                  ? XO(
"The project sample rate (%d) is not supported by the current output\nfile format. ")
                       .Format( rate )
                  : XO(
"The project sample rate (%d) and bit rate (%d kbps) combination is not\nsupported by the current output file format. ")
                       .Format( rate, bitrate/1000))
               + XO("You may resample to one of the rates below.")
            );
         }
         S.EndHorizontalLay();

         S.StartHorizontalLay(wxALIGN_CENTER, false);
         {
            choice = S.AddChoice(XO("Sample Rates"),
               [&]{
                  TranslatableStrings choices;
                  for (int i = 0; sampRates[i] > 0; i++)
                  {
                     int label = sampRates[i];
                     if ((!lowrate || label >= lowrate) && (!highrate || label <= highrate))
                     {
                        wxString name = wxString::Format(wxT("%d"),label);
                        choices.push_back( Verbatim( name ) );
                        if (label <= rate)
                           selected = i;
                     }
                  }
                  return choices;
               }(),
               std::max( 0, selected )
            );
         }
         S.EndHorizontalLay();
      }
      S.EndStatic();

      S.AddStandardButtons();
   }
   S.EndVerticalLay();

   d.Layout();
   d.Fit();
   d.SetMinSize(d.GetSize());
   d.Center();

   if (d.ShowModal() == wxID_CANCEL) {
      return 0;
   }

   return wxAtoi(choice->GetStringSelection());
#endif
}

static ExportPluginRegistry::RegisteredPlugin sRegisteredPlugin{ "FFmpeg",
   []{ return std::make_unique< ExportFFmpeg >(); }
};