Implement basic mixing functionality.

Only downmixing to a pre-defined set of speaker layouts is currently supported.
If a stream with fewer channels is being played, it'll be filled with empty channels.

13 files changed, 438 insertions, 17 deletions

diff --git a/decoder/LAVAudio/AudioSettingsProp.cpp b/decoder/LAVAudio/AudioSettingsProp.cpp
index d2b1450e..9861b99d 100644
--- a/decoder/LAVAudio/AudioSettingsProp.cpp
+++ b/decoder/LAVAudio/AudioSettingsProp.cpp
@@ -325,6 +325,152 @@ INT_PTR CLAVAudioSettingsProp::OnReceiveMessage(HWND hwnd, UINT uMsg, WPARAM wPa
 }
 
 /////////////////////////////////////////////////////////////////////////////////////////////////////////
+// Mixer Configurations
+
+CLAVAudioMixingProp::CLAVAudioMixingProp(LPUNKNOWN pUnk, HRESULT* phr)
+  : CBaseDSPropPage(NAME("LAVCAudioMixing"), pUnk, IDD_PROPPAGE_AUDIO_MIXING, IDS_MIXER), m_pAudioSettings(NULL)
+{
+}
+
+
+CLAVAudioMixingProp::~CLAVAudioMixingProp()
+{
+}
+
+HRESULT CLAVAudioMixingProp::OnConnect(IUnknown *pUnk)
+{
+  if (pUnk == NULL)
+  {
+    return E_POINTER;
+  }
+  ASSERT(m_pAudioSettings == NULL);
+  return pUnk->QueryInterface(&m_pAudioSettings);
+}
+
+HRESULT CLAVAudioMixingProp::OnDisconnect()
+{
+  SafeRelease(&m_pAudioSettings);
+  return S_OK;
+}
+
+static DWORD dwSpkLayouts[] = {
+  AV_CH_LAYOUT_STEREO,
+  AV_CH_LAYOUT_2_2,
+  AV_CH_LAYOUT_5POINT1_BACK,
+  AV_CH_LAYOUT_6POINT1,
+  AV_CH_LAYOUT_7POINT1,
+};
+static DWORD get_speaker_index(DWORD dwLayout) {
+  int i = 0;
+  for(i = 0; i < countof(dwSpkLayouts); i++) {
+    if (dwSpkLayouts[i] == dwLayout)
+      return i;
+  }
+  return (DWORD)-1;
+}
+
+HRESULT CLAVAudioMixingProp::OnApplyChanges()
+{
+  ASSERT(m_pAudioSettings != NULL);
+  HRESULT hr = S_OK;
+  DWORD dwVal = 0;
+  BOOL bVal = FALSE;
+
+  dwVal = (DWORD)SendDlgItemMessage(m_Dlg, IDC_OUTPUT_SPEAKERS, CB_GETCURSEL, 0, 0);
+  m_pAudioSettings->SetMixingLayout(dwSpkLayouts[dwVal]);
+
+  bVal = (BOOL)SendDlgItemMessage(m_Dlg, IDC_MIXING, BM_GETCHECK, 0, 0);
+  m_pAudioSettings->SetMixingEnabled(bVal);
+
+  DWORD dwMixingFlags = 0;
+  bVal = (BOOL)SendDlgItemMessage(m_Dlg, IDC_UNTOUCHED_STEREO, BM_GETCHECK, 0, 0);
+  if (bVal) dwMixingFlags |= LAV_MIXING_FLAG_UNTOUCHED_STEREO;
+
+  m_pAudioSettings->SetMixingFlags(dwMixingFlags);
+
+  LoadData();
+
+  return hr;
+}
+
+HRESULT CLAVAudioMixingProp::OnActivate()
+{
+  HRESULT hr = S_OK;
+  INITCOMMONCONTROLSEX icc;
+  icc.dwSize = sizeof(INITCOMMONCONTROLSEX);
+  icc.dwICC = ICC_BAR_CLASSES | ICC_STANDARD_CLASSES;
+  if (InitCommonControlsEx(&icc) == FALSE)
+  {
+    return E_FAIL;
+  }
+  ASSERT(m_pAudioSettings != NULL);
+
+  WCHAR spkStereo[] = L"Stereo";
+  WCHAR spkQuadro[] = L"4.0";
+  WCHAR spk51Surround[] = L"5.1";
+  WCHAR spk61Surround[] = L"6.1";
+  WCHAR spk71Surround[] = L"7.1";
+
+  SendDlgItemMessage(m_Dlg, IDC_OUTPUT_SPEAKERS, CB_RESETCONTENT, 0, 0);
+  SendDlgItemMessage(m_Dlg, IDC_OUTPUT_SPEAKERS, CB_ADDSTRING, 0, (LPARAM)spkStereo);
+  SendDlgItemMessage(m_Dlg, IDC_OUTPUT_SPEAKERS, CB_ADDSTRING, 0, (LPARAM)spkQuadro);
+  SendDlgItemMessage(m_Dlg, IDC_OUTPUT_SPEAKERS, CB_ADDSTRING, 0, (LPARAM)spk51Surround);
+  SendDlgItemMessage(m_Dlg, IDC_OUTPUT_SPEAKERS, CB_ADDSTRING, 0, (LPARAM)spk61Surround);
+  SendDlgItemMessage(m_Dlg, IDC_OUTPUT_SPEAKERS, CB_ADDSTRING, 0, (LPARAM)spk71Surround);
+
+  hr = LoadData();
+  if (SUCCEEDED(hr)) {
+    SendDlgItemMessage(m_Dlg, IDC_MIXING, BM_SETCHECK, m_bMixing, 0);
+    SendDlgItemMessage(m_Dlg, IDC_OUTPUT_SPEAKERS, CB_SETCURSEL, get_speaker_index(m_dwSpeakerLayout), 0);
+
+    SendDlgItemMessage(m_Dlg, IDC_UNTOUCHED_STEREO, BM_SETCHECK, !!(m_dwFlags & LAV_MIXING_FLAG_UNTOUCHED_STEREO), 0);
+  }
+
+  return hr;
+}
+
+HRESULT CLAVAudioMixingProp::LoadData()
+{
+  HRESULT hr = S_OK;
+
+  m_dwSpeakerLayout = m_pAudioSettings->GetMixingLayout();
+  m_bMixing         = m_pAudioSettings->GetMixingEnabled();
+  m_dwFlags         = m_pAudioSettings->GetMixingFlags();
+
+  return hr;
+}
+
+INT_PTR CLAVAudioMixingProp::OnReceiveMessage(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+  LRESULT lValue;
+  switch (uMsg)
+  {
+  case WM_COMMAND:
+    if (HIWORD(wParam) == CBN_SELCHANGE && LOWORD(wParam) == IDC_OUTPUT_SPEAKERS) {
+      lValue = SendDlgItemMessage(m_Dlg, LOWORD(wParam), CB_GETCURSEL, 0, 0);
+      if (lValue != m_dwSpeakerLayout) {
+        SetDirty();
+      }
+    } else if (LOWORD(wParam) == IDC_MIXING && HIWORD(wParam) == BN_CLICKED) {
+      lValue = SendDlgItemMessage(m_Dlg, LOWORD(wParam), BM_GETCHECK, 0, 0);
+      if (lValue != m_bMixing) {
+        SetDirty();
+      }
+    } else if (LOWORD(wParam) == IDC_UNTOUCHED_STEREO && HIWORD(wParam) == BN_CLICKED) {
+      lValue = SendDlgItemMessage(m_Dlg, LOWORD(wParam), BM_GETCHECK, 0, 0);
+      if (lValue == !(m_dwFlags & LAV_MIXING_FLAG_UNTOUCHED_STEREO)) {
+        SetDirty();
+      }
+    }
+    break;
+  case WM_HSCROLL:
+    break;
+  }
+  // Let the parent class handle the message.
+  return __super::OnReceiveMessage(hwnd, uMsg, wParam, lParam);
+}
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////////
 // Format Configurations
 
 CLAVAudioFormatsProp::CLAVAudioFormatsProp(LPUNKNOWN pUnk, HRESULT* phr)
diff --git a/decoder/LAVAudio/AudioSettingsProp.h b/decoder/LAVAudio/AudioSettingsProp.h
index 60c005fd..7e01e3ab 100644
--- a/decoder/LAVAudio/AudioSettingsProp.h
+++ b/decoder/LAVAudio/AudioSettingsProp.h
@@ -27,6 +27,10 @@
 DEFINE_GUID(CLSID_LAVAudioSettingsProp, 
 0x2d8f1801, 0xa70d, 0x48f4, 0xb7, 0x6b, 0x7f, 0x5a, 0xe0, 0x22, 0xab, 0x54);
 
+// {C89FC33C-E60A-4C97-BEF4-ACC5762B6404}
+DEFINE_GUID(CLSID_LAVAudioMixingProp,
+0xc89fc33c, 0xe60a, 0x4c97, 0xbe, 0xf4, 0xac, 0xc5, 0x76, 0x2b, 0x64, 0x4);
+
 // {20ED4A03-6AFD-4FD9-980B-2F6143AA0892}
 DEFINE_GUID(CLSID_LAVAudioStatusProp, 
 0x20ed4a03, 0x6afd, 0x4fd9, 0x98, 0xb, 0x2f, 0x61, 0x43, 0xaa, 0x8, 0x92);
@@ -76,6 +80,38 @@ private:
   int  m_iAudioDelay;
 };
 
+class CLAVAudioMixingProp : public CBaseDSPropPage
+{
+public:
+  CLAVAudioMixingProp(LPUNKNOWN pUnk, HRESULT* phr);
+  ~CLAVAudioMixingProp();
+
+  HRESULT OnActivate();
+  HRESULT OnConnect(IUnknown *pUnk);
+  HRESULT OnDisconnect();
+  HRESULT OnApplyChanges();
+  INT_PTR OnReceiveMessage(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
+
+private:
+  HRESULT LoadData();
+
+  void SetDirty()
+  {
+    m_bDirty = TRUE;
+    if (m_pPageSite)
+    {
+      m_pPageSite->OnStatusChange(PROPPAGESTATUS_DIRTY);
+    }
+  }
+
+private:
+  ILAVAudioSettings *m_pAudioSettings;
+
+  BOOL  m_bMixing;
+  DWORD m_dwSpeakerLayout;
+  DWORD m_dwFlags;
+};
+
 class CLAVAudioFormatsProp : public CBaseDSPropPage
 {
 public:
diff --git a/decoder/LAVAudio/LAVAudio.cpp b/decoder/LAVAudio/LAVAudio.cpp
index a3c3b0ef..833f0bcb 100644
--- a/decoder/LAVAudio/LAVAudio.cpp
+++ b/decoder/LAVAudio/LAVAudio.cpp
@@ -83,6 +83,8 @@ CLAVAudio::CLAVAudio(LPUNKNOWN pUnk, HRESULT* phr)
   , m_bNeedSyncpoint(FALSE)
   , m_dRate(1.0)
   , m_bInputPadded(FALSE)
+  , m_avrContext(NULL)
+  , m_bAVResampleFailed(FALSE)
 {
 #ifdef DEBUG
   DbgSetModuleLevel (LOG_CUSTOM1, DWORD_MAX); // FFMPEG messages use custom1
@@ -189,6 +191,10 @@ HRESULT CLAVAudio::LoadDefaults()
   m_settings.AudioDelayEnabled = FALSE;
   m_settings.AudioDelay = 0;
 
+  m_settings.MixingEnabled = FALSE;
+  m_settings.MixingLayout  = AV_CH_LAYOUT_STEREO;
+  m_settings.MixingFlags   = 0;
+
   return S_OK;
 }
 
@@ -251,6 +257,15 @@ HRESULT CLAVAudio::LoadSettings()
   bFlag = reg.ReadBOOL(L"OutputStandardLayout", hr);
   if (SUCCEEDED(hr)) m_settings.OutputStandardLayout = bFlag;
 
+  bFlag = reg.ReadBOOL(L"Mixing", hr);
+  if (SUCCEEDED(hr)) m_settings.MixingEnabled = bFlag;
+
+  dwVal = reg.ReadDWORD(L"MixingLayout", hr);
+  if (SUCCEEDED(hr)) m_settings.MixingLayout = dwVal;
+
+  dwVal = reg.ReadDWORD(L"MixingFlags", hr);
+  if (SUCCEEDED(hr)) m_settings.MixingFlags = dwVal;
+
   // Deprecated sample format storage
   pBuf = reg.ReadBinary(L"SampleFormats", dwVal, hr);
   if (SUCCEEDED(hr)) {
@@ -307,6 +322,10 @@ HRESULT CLAVAudio::SaveSettings()
     reg.WriteBOOL(L"AudioDelayEnabled", m_settings.AudioDelayEnabled);
     reg.WriteDWORD(L"AudioDelay", m_settings.AudioDelay);
 
+    reg.WriteBOOL(L"Mixing", m_settings.MixingEnabled);
+    reg.WriteDWORD(L"MixingLayout", m_settings.MixingLayout);
+    reg.WriteDWORD(L"MixingFlags", m_settings.MixingFlags);
+
     reg.DeleteKey(L"Formats");
     CRegistry regF = CRegistry(HKEY_CURRENT_USER, LAVC_AUDIO_REGISTRY_KEY_FORMATS, hr);
     for (int i = 0; i < Codec_NB; ++i) {
@@ -346,6 +365,11 @@ void CLAVAudio::ffmpeg_shutdown()
     m_pParser = NULL;
   }
 
+  if (m_avrContext) {
+    avresample_close(m_avrContext);
+    avresample_free(&m_avrContext);
+  }
+
   FreeBitstreamContext();
 
   FreeDTSDecoder();
@@ -373,15 +397,16 @@ STDMETHODIMP CLAVAudio::GetPages(CAUUID *pPages)
 {
   CheckPointer(pPages, E_POINTER);
   BOOL bShowStatusPage = m_pInput && m_pInput->IsConnected();
-  pPages->cElems = bShowStatusPage ? 3 : 2;
+  pPages->cElems = bShowStatusPage ? 4 : 3;
   pPages->pElems = (GUID *)CoTaskMemAlloc(sizeof(GUID) * pPages->cElems);
   if (pPages->pElems == NULL) {
     return E_OUTOFMEMORY;
   }
   pPages->pElems[0] = CLSID_LAVAudioSettingsProp;
-  pPages->pElems[1] = CLSID_LAVAudioFormatsProp;
+  pPages->pElems[1] = CLSID_LAVAudioMixingProp;
+  pPages->pElems[2] = CLSID_LAVAudioFormatsProp;
   if (bShowStatusPage)
-    pPages->pElems[2] = CLSID_LAVAudioStatusProp;
+    pPages->pElems[3] = CLSID_LAVAudioStatusProp;
   return S_OK;
 }
 
@@ -395,6 +420,8 @@ STDMETHODIMP CLAVAudio::CreatePage(const GUID& guid, IPropertyPage** ppPage)
 
   if (guid == CLSID_LAVAudioSettingsProp)
     *ppPage = new CLAVAudioSettingsProp(NULL, &hr);
+  else if (guid == CLSID_LAVAudioMixingProp)
+    *ppPage = new CLAVAudioMixingProp(NULL, &hr);
   else if (guid == CLSID_LAVAudioFormatsProp)
     *ppPage = new CLAVAudioFormatsProp(NULL, &hr);
   else if (guid == CLSID_LAVAudioStatusProp)
@@ -601,6 +628,45 @@ STDMETHODIMP CLAVAudio::SetAudioDelay(BOOL bEnabled, int delay)
   return S_OK;
 }
 
+STDMETHODIMP CLAVAudio::SetMixingEnabled(BOOL bEnabled)
+{
+  m_settings.MixingEnabled = bEnabled;
+  SaveSettings();
+
+  return S_OK;
+}
+
+STDMETHODIMP_(BOOL) CLAVAudio::GetMixingEnabled()
+{
+  return m_settings.MixingEnabled;
+}
+
+STDMETHODIMP CLAVAudio::SetMixingLayout(DWORD dwLayout)
+{
+  m_settings.MixingLayout = dwLayout;
+  SaveSettings();
+
+  return S_OK;
+}
+
+STDMETHODIMP_(DWORD) CLAVAudio::GetMixingLayout()
+{
+  return m_settings.MixingLayout;
+}
+
+STDMETHODIMP CLAVAudio::SetMixingFlags(DWORD dwFlags)
+{
+  m_settings.MixingFlags = dwFlags;
+  SaveSettings();
+
+  return S_OK;
+}
+
+STDMETHODIMP_(DWORD) CLAVAudio::GetMixingFlags()
+{
+  return m_settings.MixingFlags;
+}
+
 // ILAVAudioStatus
 BOOL CLAVAudio::IsSampleFormatSupported(LAVAudioSampleFormat sfCheck)
 {
@@ -1651,6 +1717,7 @@ HRESULT CLAVAudio::Decode(const BYTE * const buffer, int buffsize, int &consumed
     // Channel re-mapping and sample format conversion
     if (got_frame && m_pFrame->nb_samples > 0) {
       const DWORD idx_start = out.bBuffer->GetCount();
+      const DWORD allocated = out.bBuffer->GetAllocated();
 
       out.wChannels = m_pAVCtx->channels;
       out.dwSamplesPerSec = m_pAVCtx->sample_rate;
@@ -1661,27 +1728,33 @@ HRESULT CLAVAudio::Decode(const BYTE * const buffer, int buffsize, int &consumed
 
       out.nSamples = m_pFrame->nb_samples;
       DWORD dwPCMSize = out.nSamples * out.wChannels * av_get_bytes_per_sample(m_pAVCtx->sample_fmt);
+      DWORD dwPCMSizeAligned = FFALIGN(out.nSamples, 32) * out.wChannels * av_get_bytes_per_sample(m_pAVCtx->sample_fmt);
 
       switch (m_pAVCtx->sample_fmt) {
       case AV_SAMPLE_FMT_U8:
+        out.bBuffer->Allocate(allocated + dwPCMSizeAligned);
         out.bBuffer->Append(m_pFrame->data[0], dwPCMSize);
         out.sfFormat = SampleFormat_U8;
         break;
       case AV_SAMPLE_FMT_S16:
+        out.bBuffer->Allocate(allocated + dwPCMSizeAligned);
         out.bBuffer->Append(m_pFrame->data[0], dwPCMSize);
         out.sfFormat = SampleFormat_16;
         break;
       case AV_SAMPLE_FMT_S32:
+        out.bBuffer->Allocate(allocated + dwPCMSizeAligned);
         out.bBuffer->Append(m_pFrame->data[0], dwPCMSize);
         out.sfFormat = SampleFormat_32;
         out.wBitsPerSample = m_pAVCtx->bits_per_raw_sample;
         break;
       case AV_SAMPLE_FMT_FLT:
+        out.bBuffer->Allocate(allocated + dwPCMSizeAligned);
         out.bBuffer->Append(m_pFrame->data[0], dwPCMSize);
         out.sfFormat = SampleFormat_FP32;
         break;
       case AV_SAMPLE_FMT_DBL:
         {
+          out.bBuffer->Allocate(allocated + (dwPCMSizeAligned / 2));
           out.bBuffer->SetSize(idx_start + (dwPCMSize / 2));
           float *pDataOut = (float *)(out.bBuffer->Ptr() + idx_start);
 
@@ -1697,6 +1770,7 @@ HRESULT CLAVAudio::Decode(const BYTE * const buffer, int buffsize, int &consumed
       // Planar Formats
       case AV_SAMPLE_FMT_U8P:
         {
+          out.bBuffer->Allocate(allocated + dwPCMSizeAligned);
           out.bBuffer->SetSize(idx_start + dwPCMSize);
           uint8_t *pOut = (uint8_t *)(out.bBuffer->Ptr() + idx_start);
 
@@ -1710,6 +1784,7 @@ HRESULT CLAVAudio::Decode(const BYTE * const buffer, int buffsize, int &consumed
         break;
       case AV_SAMPLE_FMT_S16P:
         {
+          out.bBuffer->Allocate(allocated + dwPCMSizeAligned);
           out.bBuffer->SetSize(idx_start + dwPCMSize);
           int16_t *pOut = (int16_t *)(out.bBuffer->Ptr() + idx_start);
 
@@ -1723,6 +1798,7 @@ HRESULT CLAVAudio::Decode(const BYTE * const buffer, int buffsize, int &consumed
         break;
       case AV_SAMPLE_FMT_S32P:
         {
+          out.bBuffer->Allocate(allocated + dwPCMSizeAligned);
           out.bBuffer->SetSize(idx_start + dwPCMSize);
           int32_t *pOut = (int32_t *)(out.bBuffer->Ptr() + idx_start);
 
@@ -1737,6 +1813,7 @@ HRESULT CLAVAudio::Decode(const BYTE * const buffer, int buffsize, int &consumed
         break;
       case AV_SAMPLE_FMT_FLTP:
         {
+          out.bBuffer->Allocate(allocated + dwPCMSizeAligned);
           out.bBuffer->SetSize(idx_start + dwPCMSize);
           float *pOut = (float *)(out.bBuffer->Ptr() + idx_start);
 
@@ -1750,6 +1827,7 @@ HRESULT CLAVAudio::Decode(const BYTE * const buffer, int buffsize, int &consumed
         break;
       case AV_SAMPLE_FMT_DBLP:
         {
+          out.bBuffer->Allocate(allocated + dwPCMSizeAligned);
           out.bBuffer->SetSize(idx_start + (dwPCMSize / 2));
           float *pOut = (float *)(out.bBuffer->Ptr() + idx_start);
 
diff --git a/decoder/LAVAudio/LAVAudio.h b/decoder/LAVAudio/LAVAudio.h
index fa150be2..aeb4de8b 100644
--- a/decoder/LAVAudio/LAVAudio.h
+++ b/decoder/LAVAudio/LAVAudio.h
@@ -132,6 +132,12 @@ public:
   STDMETHODIMP SetSampleFormat(LAVAudioSampleFormat format, BOOL bEnabled);
   STDMETHODIMP GetAudioDelay(BOOL *pbEnabled, int *pDelay);
   STDMETHODIMP SetAudioDelay(BOOL bEnabled, int delay);
+  STDMETHODIMP SetMixingEnabled(BOOL bEnabled);
+  STDMETHODIMP_(BOOL) GetMixingEnabled();
+  STDMETHODIMP SetMixingLayout(DWORD dwLayout);
+  STDMETHODIMP_(DWORD) GetMixingLayout();
+  STDMETHODIMP SetMixingFlags(DWORD dwFlags);
+  STDMETHODIMP_(DWORD) GetMixingFlags();
 
   // ILAVAudioStatus
   STDMETHODIMP_(BOOL) IsSampleFormatSupported(LAVAudioSampleFormat sfCheck);
@@ -224,6 +230,8 @@ private:
   HRESULT ConvertSampleFormat(BufferDetails *pcm, LAVAudioSampleFormat outputFormat);
   HRESULT Truncate32Buffer(BufferDetails *buffer);
 
+  HRESULT PerformMixing(BufferDetails *buffer);
+
 private:
   CodecID              m_nCodecId;       // FFMPEG Codec Id
   AVCodec              *m_pAVCodec;      // AVCodec reference
@@ -256,6 +264,11 @@ private:
 
   BOOL                 m_bInputPadded;
 
+  AVAudioResampleContext *m_avrContext;
+  LAVAudioSampleFormat m_sfRemixFormat;
+  DWORD                m_dwRemixLayout;
+  BOOL                 m_bAVResampleFailed;
+
   // Settings
   struct AudioSettings {
     BOOL DRCEnabled;
@@ -271,6 +284,10 @@ private:
     BOOL bSampleFormats[SampleFormat_NB];
     BOOL AudioDelayEnabled;
     int  AudioDelay;
+
+    BOOL MixingEnabled;
+    DWORD MixingLayout;
+    DWORD MixingFlags;
   } m_settings;
   BOOL                m_bRuntimeConfig;
 
diff --git a/decoder/LAVAudio/LAVAudio.rc b/decoder/LAVAudio/LAVAudio.rc
index 949bf3d6..1e6dd81d 100644
--- a/decoder/LAVAudio/LAVAudio.rc
+++ b/decoder/LAVAudio/LAVAudio.rc
@@ -105,6 +105,18 @@ BEGIN
     CONTROL         "",IDC_DELAYSPIN,"msctls_updown32",UDS_SETBUDDYINT | UDS_ALIGNRIGHT | UDS_AUTOBUDDY | UDS_ARROWKEYS | UDS_NOTHOUSANDS | UDS_HOTTRACK,305,35,11,13
 END
 
+IDD_PROPPAGE_AUDIO_MIXING DIALOGEX 0, 0, 369, 215
+STYLE DS_SETFONT | DS_FIXEDSYS | WS_CHILD
+FONT 8, "MS Shell Dlg", 400, 0, 0x0
+BEGIN
+    GROUPBOX        "Mixer",IDC_LBL_MIXING,7,7,214,67
+    CONTROL         "Enable Mixing",IDC_MIXING,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,14,19,59,10
+    LTEXT           "Output Speaker Configuration:",IDC_LBL_OUTPUT_SPEAKERS,15,32,100,8
+    COMBOBOX        IDC_OUTPUT_SPEAKERS,121,30,90,30,CBS_DROPDOWNLIST | WS_VSCROLL | WS_TABSTOP
+    GROUPBOX        "Settings",IDC_MIX_SETTINGS,225,7,133,53
+    CONTROL         "Don't mix Stereo sources",IDC_UNTOUCHED_STEREO,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,237,19,100,10
+END
+
 IDD_PROPPAGE_FORMATS DIALOGEX 0, 0, 369, 215
 STYLE DS_SETFONT | DS_FIXEDSYS | WS_CHILD
 FONT 8, "MS Shell Dlg", 400, 0, 0x0
@@ -177,6 +189,14 @@ BEGIN
         BOTTOMMARGIN, 210
     END
 
+    IDD_PROPPAGE_AUDIO_MIXING, DIALOG
+    BEGIN
+        LEFTMARGIN, 7
+        RIGHTMARGIN, 358
+        TOPMARGIN, 7
+        BOTTOMMARGIN, 210
+    END
+
     IDD_PROPPAGE_FORMATS, DIALOG
     BEGIN
         LEFTMARGIN, 7
@@ -206,6 +226,7 @@ BEGIN
     IDS_SETTINGS            "Audio Settings"
     IDS_STATUS              "Status"
     IDS_FORMATS             "Formats"
+    IDS_MIXER               "Mixing"
 END
 
 #endif    // English (United States) resources
diff --git a/decoder/LAVAudio/LAVAudio.vcxproj b/decoder/LAVAudio/LAVAudio.vcxproj
index 7cf850a1..8da1af88 100644
--- a/decoder/LAVAudio/LAVAudio.vcxproj
+++ b/decoder/LAVAudio/LAVAudio.vcxproj
@@ -92,7 +92,7 @@
     <Link>
       <SubSystem>Windows</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>advapi32.lib;ole32.lib;winmm.lib;user32.lib;oleaut32.lib;shell32.lib;Shlwapi.lib;Comctl32.lib;strmbasd.lib;dsutild.lib;avformat-lav.lib;avutil-lav.lib;avcodec-lav.lib</AdditionalDependencies>
+      <AdditionalDependencies>advapi32.lib;ole32.lib;winmm.lib;user32.lib;oleaut32.lib;shell32.lib;Shlwapi.lib;Comctl32.lib;strmbasd.lib;dsutild.lib;avformat-lav.lib;avutil-lav.lib;avcodec-lav.lib;avresample-lav.lib</AdditionalDependencies>
       <ModuleDefinitionFile>LAVAudio.def</ModuleDefinitionFile>
     </Link>
   </ItemDefinitionGroup>
@@ -103,7 +103,7 @@
     <Link>
       <SubSystem>Windows</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>advapi32.lib;ole32.lib;winmm.lib;user32.lib;oleaut32.lib;shell32.lib;Shlwapi.lib;Comctl32.lib;strmbasd.lib;dsutild.lib;avformat-lav.lib;avutil-lav.lib;avcodec-lav.lib</AdditionalDependencies>
+      <AdditionalDependencies>advapi32.lib;ole32.lib;winmm.lib;user32.lib;oleaut32.lib;shell32.lib;Shlwapi.lib;Comctl32.lib;strmbasd.lib;dsutild.lib;avformat-lav.lib;avutil-lav.lib;avcodec-lav.lib;avresample-lav.lib</AdditionalDependencies>
       <ModuleDefinitionFile>LAVAudio.def</ModuleDefinitionFile>
     </Link>
   </ItemDefinitionGroup>
@@ -116,7 +116,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>advapi32.lib;ole32.lib;winmm.lib;user32.lib;oleaut32.lib;shell32.lib;Shlwapi.lib;Comctl32.lib;strmbase.lib;dsutil.lib;avformat-lav.lib;avutil-lav.lib;avcodec-lav.lib</AdditionalDependencies>
+      <AdditionalDependencies>advapi32.lib;ole32.lib;winmm.lib;user32.lib;oleaut32.lib;shell32.lib;Shlwapi.lib;Comctl32.lib;strmbase.lib;dsutil.lib;avformat-lav.lib;avutil-lav.lib;avcodec-lav.lib;avresample-lav.lib</AdditionalDependencies>
       <ModuleDefinitionFile>LAVAudio.def</ModuleDefinitionFile>
     </Link>
     <CustomBuildStep>
@@ -134,7 +134,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>advapi32.lib;ole32.lib;winmm.lib;user32.lib;oleaut32.lib;shell32.lib;Shlwapi.lib;Comctl32.lib;strmbase.lib;dsutil.lib;avformat-lav.lib;avutil-lav.lib;avcodec-lav.lib</AdditionalDependencies>
+      <AdditionalDependencies>advapi32.lib;ole32.lib;winmm.lib;user32.lib;oleaut32.lib;shell32.lib;Shlwapi.lib;Comctl32.lib;strmbase.lib;dsutil.lib;avformat-lav.lib;avutil-lav.lib;avcodec-lav.lib;avresample-lav.lib</AdditionalDependencies>
       <ModuleDefinitionFile>LAVAudio.def</ModuleDefinitionFile>
     </Link>
     <CustomBuildStep>
diff --git a/decoder/LAVAudio/LAVAudioSettings.h b/decoder/LAVAudio/LAVAudioSettings.h
index 221fd7eb..6c1dbf75 100644
--- a/decoder/LAVAudio/LAVAudioSettings.h
+++ b/decoder/LAVAudio/LAVAudioSettings.h
@@ -138,6 +138,19 @@ interface ILAVAudioSettings : public IUnknown
   // Configure a delay for the audio
   STDMETHOD(GetAudioDelay)(BOOL *pbEnabled, int *pDelay) = 0;
   STDMETHOD(SetAudioDelay)(BOOL bEnabled, int delay) = 0;
+
+  // Enable/Disable Mixing
+  STDMETHOD(SetMixingEnabled)(BOOL bEnabled) = 0;
+  STDMETHOD_(BOOL,GetMixingEnabled)() = 0;
+
+  // Control Mixing Layout
+  STDMETHOD(SetMixingLayout)(DWORD dwLayout) = 0;
+  STDMETHOD_(DWORD,GetMixingLayout)() = 0;
+
+#define LAV_MIXING_FLAG_UNTOUCHED_STEREO 0x0001
+  // Enable/Disable Mixing
+  STDMETHOD(SetMixingFlags)(DWORD dwFlags) = 0;
+  STDMETHOD_(DWORD,GetMixingFlags)() = 0;
 };
 
 // LAV Audio Status Interface
diff --git a/decoder/LAVAudio/Media.cpp b/decoder/LAVAudio/Media.cpp
index 960b7d0e..59e59f14 100644
--- a/decoder/LAVAudio/Media.cpp
+++ b/decoder/LAVAudio/Media.cpp
@@ -370,6 +370,29 @@ LAVAudioSampleFormat get_lav_sample_fmt(AVSampleFormat sample_fmt, int bits)
   return lav_sample_fmt;
 }
 
+AVSampleFormat get_ff_sample_fmt(LAVAudioSampleFormat sample_fmt)
+{
+  AVSampleFormat ff_sample_fmt;
+  switch(sample_fmt) {
+  case SampleFormat_16:
+    ff_sample_fmt = AV_SAMPLE_FMT_S16;
+    break;
+  case SampleFormat_32:
+    ff_sample_fmt = AV_SAMPLE_FMT_S32;
+    break;
+  case SampleFormat_FP32:
+    ff_sample_fmt = AV_SAMPLE_FMT_FLT;
+    break;
+  case SampleFormat_U8:
+    ff_sample_fmt = AV_SAMPLE_FMT_U8;
+    break;
+  case SampleFormat_24:
+    assert(0);
+    break;
+  }
+  return ff_sample_fmt;
+}
+
 static BYTE get_lpcm_sample_rate_index(int sample_rate)
 {
   switch(sample_rate) {
diff --git a/decoder/LAVAudio/Media.h b/decoder/LAVAudio/Media.h
index 92988ae9..0fcdc28f 100644
--- a/decoder/LAVAudio/Media.h
+++ b/decoder/LAVAudio/Media.h
@@ -57,6 +57,7 @@ const char *get_sample_format_desc(CMediaType &mt);
 BYTE get_byte_per_sample(LAVAudioSampleFormat sfFormat);
 
 LAVAudioSampleFormat get_lav_sample_fmt(AVSampleFormat sample_fmt, int bits = 0);
+AVSampleFormat get_ff_sample_fmt(LAVAudioSampleFormat sample_fmt);
 
 WORD get_channel_from_flag(DWORD dwMask, DWORD dwFlag);
 DWORD get_flag_from_channel(DWORD dwMask, WORD wChannel);
diff --git a/decoder/LAVAudio/PostProcessor.cpp b/decoder/LAVAudio/PostProcessor.cpp
index aa6b8141..8345e3e6 100644
--- a/decoder/LAVAudio/PostProcessor.cpp
+++ b/decoder/LAVAudio/PostProcessor.cpp
@@ -547,13 +547,71 @@ HRESULT CLAVAudio::Truncate32Buffer(BufferDetails *buffer)
   return S_OK;
 }
 
-HRESULT CLAVAudio::PostProcess(BufferDetails *buffer)
+HRESULT CLAVAudio::PerformMixing(BufferDetails *buffer)
 {
-  LAVAudioSampleFormat outputFormat = GetBestAvailableSampleFormat(buffer->sfFormat);
-  if (outputFormat != buffer->sfFormat) {
-    ConvertSampleFormat(buffer, outputFormat);
+  // Check if we need mixing, either already in target mask or in stereo (no downmixing from stereo)
+  if (buffer->dwChannelMask == m_settings.MixingLayout || (buffer->wChannels <= 2 && (m_settings.MixingFlags & LAV_MIXING_FLAG_UNTOUCHED_STEREO)))
+    return S_FALSE;
+
+  // Sadly, we need to convert this, avresample has no 24-bit mode
+  if (buffer->sfFormat == SampleFormat_24) {
+    ConvertSampleFormat(buffer, SampleFormat_32);
   }
 
+  if (buffer->dwChannelMask != m_DecodeLayoutSanified || (!m_avrContext && !m_bAVResampleFailed) || m_settings.MixingLayout != m_dwRemixLayout) {
+    m_bAVResampleFailed = FALSE;
+    if (m_avrContext) {
+      avresample_close(m_avrContext);
+      avresample_free(&m_avrContext);
+    }
+
+    m_DecodeLayoutSanified = buffer->dwChannelMask;
+    // We prefer to mix to FP32, so try to use that
+    m_sfRemixFormat = GetBestAvailableSampleFormat(SampleFormat_FP32);
+    // avresample has no 24-bit mode
+    if (m_sfRemixFormat == SampleFormat_24)
+      m_sfRemixFormat = SampleFormat_32;
+
+    m_avrContext = avresample_alloc_context();
+    av_opt_set_int(m_avrContext, "in_channel_layout", buffer->dwChannelMask, 0);
+    av_opt_set_int(m_avrContext, "in_sample_fmt", get_ff_sample_fmt(buffer->sfFormat), 0);
+
+    av_opt_set_int(m_avrContext, "out_channel_layout", m_settings.MixingLayout, 0);
+    av_opt_set_int(m_avrContext, "out_sample_fmt", get_ff_sample_fmt(m_sfRemixFormat), 0);
+
+    int ret = avresample_open(m_avrContext);
+    if (ret < 0) {
+      DbgLog((LOG_ERROR, 10, L"avresample_open failed, layout in: %x, out: %x, sample fmt in: %d, out: %d", buffer->dwChannelMask, m_settings.MixingLayout, buffer->sfFormat, m_sfRemixFormat));
+      avresample_free(&m_avrContext);
+      m_bAVResampleFailed = TRUE;
+    }
+
+    m_dwRemixLayout = m_settings.MixingLayout;
+  }
+
+  if (!m_avrContext)
+    return S_FALSE;
+
+  GrowableArray<BYTE> *pcmOut = new GrowableArray<BYTE>();
+  pcmOut->Allocate(FFALIGN(buffer->nSamples, 32) * av_get_channel_layout_nb_channels(m_dwRemixLayout) * get_byte_per_sample(m_sfRemixFormat));
+  BYTE *pOut = pcmOut->Ptr();
+
+  BYTE *pIn = buffer->bBuffer->Ptr();
+  avresample_convert(m_avrContext, (void **)&pOut, pcmOut->GetAllocated(), buffer->nSamples, (void **)&pIn, buffer->bBuffer->GetAllocated(), buffer->nSamples);
+
+  delete buffer->bBuffer;
+  buffer->bBuffer = pcmOut;
+  buffer->dwChannelMask = m_dwRemixLayout;
+  buffer->sfFormat = m_sfRemixFormat;
+  buffer->wBitsPerSample = get_byte_per_sample(m_sfRemixFormat) << 3;
+  buffer->wChannels = av_get_channel_layout_nb_channels(m_dwRemixLayout);
+  buffer->bBuffer->SetSize(buffer->wChannels * buffer->nSamples * get_byte_per_sample(m_sfRemixFormat));
+
+  return S_OK;
+}
+
+HRESULT CLAVAudio::PostProcess(BufferDetails *buffer)
+{
   buffer->dwChannelMask = sanitize_mask(buffer->dwChannelMask, m_nCodecId);
 
   int layout_channels = av_get_channel_layout_nb_channels(buffer->dwChannelMask);
@@ -563,8 +621,11 @@ HRESULT CLAVAudio::PostProcess(BufferDetails *buffer)
     buffer->dwChannelMask = get_channel_mask(buffer->wChannels);
   }
 
+  if (m_settings.MixingEnabled) {
+    PerformMixing(buffer);
+  }
   // Remap to standard configurations, if requested
-  if (m_settings.OutputStandardLayout) {
+  else if (m_settings.OutputStandardLayout) {
     if (buffer->dwChannelMask != m_DecodeLayoutSanified) {
       m_DecodeLayoutSanified = buffer->dwChannelMask;
       CheckChannelLayoutConformity(buffer->dwChannelMask);
@@ -593,8 +654,16 @@ HRESULT CLAVAudio::PostProcess(BufferDetails *buffer)
     UpdateVolumeStats(*buffer);
   }
 
-  if (buffer->sfFormat == SampleFormat_32 && buffer->wBitsPerSample && buffer->wBitsPerSample <= 24) {
+  // Truncate 24-in-32 to real 24
+  if (buffer->sfFormat == SampleFormat_32 && GetSampleFormat(SampleFormat_24) && buffer->wBitsPerSample && buffer->wBitsPerSample <= 24) {
     Truncate32Buffer(buffer);
   }
+
+  // Convert Sample format, if necessary
+  LAVAudioSampleFormat outputFormat = GetBestAvailableSampleFormat(buffer->sfFormat);
+  if (outputFormat != buffer->sfFormat) {
+    ConvertSampleFormat(buffer, outputFormat);
+  }
+
   return S_OK;
 }
diff --git a/decoder/LAVAudio/dllmain.cpp b/decoder/LAVAudio/dllmain.cpp
index 73c5fe26..107b69b7 100644
--- a/decoder/LAVAudio/dllmain.cpp
+++ b/decoder/LAVAudio/dllmain.cpp
@@ -76,6 +76,12 @@ CFactoryTemplate g_Templates[] = {
       NULL, NULL
   },
   { 
+      L"LAV Audio Mixer",
+      &CLSID_LAVAudioMixingProp,
+      CreateInstance<CLAVAudioMixingProp>,
+      NULL, NULL
+  },
+  {
     L"LAV Audio Format Settings",
       &CLSID_LAVAudioFormatsProp,
       CreateInstance<CLAVAudioFormatsProp>,
diff --git a/decoder/LAVAudio/resource.h b/decoder/LAVAudio/resource.h
index 41fbc4ab..6bbf9149 100644
--- a/decoder/LAVAudio/resource.h
+++ b/decoder/LAVAudio/resource.h
@@ -3,12 +3,14 @@
 // Used by LAVAudio.rc
 //
 #define IDD_PROPPAGE_AUDIO_SETTINGS     9
-#define IDD_PROPPAGE_FORMATS            10
-#define IDD_PROPPAGE_STATUS             11
+#define IDD_PROPPAGE_AUDIO_MIXING       10
+#define IDD_PROPPAGE_FORMATS            11
+#define IDD_PROPPAGE_STATUS             12
 #define IDS_SETTINGS                    101
 #define IDS_STATUS                      102
 #define IDS_FORMATS                     103
 #define IDI_ICON1                       104
+#define IDS_MIXER                       105
 #define IDC_INPUT_STATUS                1013
 #define IDC_SUP_SAMPLE_FORMATS          1020
 #define IDC_INT16                       1021
@@ -85,14 +87,22 @@
 #define IDC_DELAY                       1101
 #define IDC_DELAYSPIN                   1102
 #define IDC_LBL_FORMATS                 1103
+#define IDC_MIXING                      1104
+#define IDC_MIXER                       1105
+#define IDC_DOWNMIX                     1106
+#define IDC_OUTPUT_SPEAKERS             1108
+#define IDC_UNTOUCHED_STEREO            1109
+#define IDC_MIX_SETTINGS                1110
+#define IDC_LBL_OUTPUT_SPEAKERS         1111
+#define IDC_LBL_MIXING                  1112
 
 // Next default values for new objects
 // 
 #ifdef APSTUDIO_INVOKED
 #ifndef APSTUDIO_READONLY_SYMBOLS
-#define _APS_NEXT_RESOURCE_VALUE        105
+#define _APS_NEXT_RESOURCE_VALUE        106
 #define _APS_NEXT_COMMAND_VALUE         40001
-#define _APS_NEXT_CONTROL_VALUE         1104
+#define _APS_NEXT_CONTROL_VALUE         1113
 #define _APS_NEXT_SYMED_VALUE           101
 #endif
 #endif
diff --git a/decoder/LAVAudio/stdafx.h b/decoder/LAVAudio/stdafx.h
index afcd70bc..ad2472d8 100644
--- a/decoder/LAVAudio/stdafx.h
+++ b/decoder/LAVAudio/stdafx.h
@@ -44,6 +44,7 @@ extern "C" {
 #include "libavcodec/avcodec.h"
 #include "libavutil/opt.h"
 #include "libavutil/intreadwrite.h"
+#include "libavresample/avresample.h"
 }
 #pragma warning(pop)