Add an option for mono mic capture in ZoomIt

src/modules/ZoomIt/ZoomIt/AudioSampleGenerator.cpp

@@ -34,13 +34,15 @@ namespace winrt
     using namespace Windows::Devices::Enumeration;
 }
 
-AudioSampleGenerator::AudioSampleGenerator(bool captureMicrophone, bool captureSystemAudio)
+AudioSampleGenerator::AudioSampleGenerator(bool captureMicrophone, bool captureSystemAudio, bool micMonoMix)
     : m_captureMicrophone(captureMicrophone)
     , m_captureSystemAudio(captureSystemAudio)
+    , m_micMonoMix(micMonoMix)
 {
     OutputDebugStringA(("AudioSampleGenerator created, captureMicrophone=" +
         std::string(captureMicrophone ? "true" : "false") +
-        ", captureSystemAudio=" + std::string(captureSystemAudio ? "true" : "false") + "\n").c_str());
+        ", captureSystemAudio=" + std::string(captureSystemAudio ? "true" : "false") +
+        ", micMonoMix=" + std::string(micMonoMix ? "true" : "false") + "\n").c_str());
     m_audioEvent.create(wil::EventOptions::ManualReset);
     m_endEvent.create(wil::EventOptions::ManualReset);
     m_startEvent.create(wil::EventOptions::ManualReset);
@@ -631,6 +633,30 @@ void AudioSampleGenerator::OnAudioQuantumStarted(winrt::AudioGraph const& sender
         uint32_t expectedSamplesPerQuantum = (m_graphSampleRate / 100) * m_graphChannels;
         uint32_t numMicSamples = audioBuffer.Length() / sizeof(float);
 
+        // Apply mono mixing to microphone audio if enabled
+        // This converts stereo mic input (with same signal on both channels) to true mono
+        // by averaging the channels and writing the result to both channels
+        if (m_micMonoMix && m_captureMicrophone && numMicSamples > 0 && m_graphChannels >= 2)
+        {
+            float* micData = reinterpret_cast<float*>(sampleBuffer.data());
+            uint32_t numFrames = numMicSamples / m_graphChannels;
+            for (uint32_t i = 0; i < numFrames; i++)
+            {
+                // Sum all channels for this frame
+                float sum = 0.0f;
+                for (uint32_t ch = 0; ch < m_graphChannels; ch++)
+                {
+                    sum += micData[i * m_graphChannels + ch];
+                }
+                // Power-preserving mix: divide by sqrt(N) to maintain perceived loudness
+                float mono = sum / std::sqrt(static_cast<float>(m_graphChannels));
+                for (uint32_t ch = 0; ch < m_graphChannels; ch++)
+                {
+                    micData[i * m_graphChannels + ch] = mono;
+                }
+            }
+        }
+
         // Drain loopback samples regardless of whether we have mic audio
         if (m_loopbackCapture)
         {

src/modules/ZoomIt/ZoomIt/AudioSampleGenerator.h

@@ -5,7 +5,7 @@
 class AudioSampleGenerator
 {
 public:
-    AudioSampleGenerator(bool captureMicrophone = true, bool captureSystemAudio = true);
+    AudioSampleGenerator(bool captureMicrophone = true, bool captureSystemAudio = true, bool micMonoMix = false);
     ~AudioSampleGenerator();
 
     winrt::Windows::Foundation::IAsyncAction InitializeAsync();
@@ -70,4 +70,5 @@ private:
     std::atomic<bool> m_started = false;
     bool m_captureMicrophone = true;
     bool m_captureSystemAudio = true;
+    bool m_micMonoMix = false;
 };

src/modules/ZoomIt/ZoomIt/VideoRecordingSession.cpp

@@ -861,6 +861,7 @@ VideoRecordingSession::VideoRecordingSession(
     uint32_t frameRate,
     bool captureAudio,
     bool captureSystemAudio,
+    bool micMonoMix,
     winrt::Streams::IRandomAccessStream const& stream)
 {
     m_device = device;
@@ -964,7 +965,7 @@ VideoRecordingSession::VideoRecordingSession(
     winrt::check_hresult(m_d3dDevice->CreateRenderTargetView(backBuffer.get(), nullptr, m_renderTargetView.put()));
 
     // Always create audio generator for loopback capture; captureAudio controls microphone
-    m_audioGenerator = std::make_unique<AudioSampleGenerator>(captureAudio, captureSystemAudio);
+    m_audioGenerator = std::make_unique<AudioSampleGenerator>(captureAudio, captureSystemAudio, micMonoMix);
 }
 
 
@@ -1112,9 +1113,10 @@ std::shared_ptr<VideoRecordingSession> VideoRecordingSession::Create(
     uint32_t frameRate,
     bool captureAudio,
     bool captureSystemAudio,
+    bool micMonoMix,
     winrt::Streams::IRandomAccessStream const& stream)
 {
-    return std::shared_ptr<VideoRecordingSession>(new VideoRecordingSession(device, item, crop, frameRate, captureAudio, captureSystemAudio, stream));
+    return std::shared_ptr<VideoRecordingSession>(new VideoRecordingSession(device, item, crop, frameRate, captureAudio, captureSystemAudio, micMonoMix, stream));
 }
 
 //----------------------------------------------------------------------------

src/modules/ZoomIt/ZoomIt/VideoRecordingSession.h

@@ -28,6 +28,7 @@ public:
         uint32_t frameRate,
         bool captureAudio,
         bool captureSystemAudio,
+        bool micMonoMix,
         winrt::Streams::IRandomAccessStream const& stream);
     ~VideoRecordingSession();
 
@@ -188,6 +189,7 @@ private:
         uint32_t frameRate,
         bool captureAudio,
         bool captureSystemAudio,
+        bool micMonoMix,
         winrt::Streams::IRandomAccessStream const& stream);
     void CloseInternal();
 

src/modules/ZoomIt/ZoomIt/ZoomIt.rc

@@ -279,6 +279,7 @@ BEGIN
     LTEXT           "To record a specific window, enter the hotkey with the Alt key in the opposite mode.",IDC_STATIC,7,55,251,19
     CONTROL         "Capture &system audio",IDC_CAPTURE_SYSTEM_AUDIO,"Button",BS_AUTOCHECKBOX | BS_LEFTTEXT | WS_TABSTOP,7,149,83,10
     CONTROL         "&Capture audio input:",IDC_CAPTURE_AUDIO,"Button",BS_AUTOCHECKBOX | BS_LEFTTEXT | WS_TABSTOP,7,161,83,10
+    CONTROL         "Mono",IDC_MIC_MONO_MIX,"Button",BS_AUTOCHECKBOX | BS_LEFTTEXT | WS_TABSTOP,98,161,30,10
     COMBOBOX        IDC_MICROPHONE,81,176,152,30,CBS_DROPDOWNLIST | WS_VSCROLL | WS_TABSTOP
     LTEXT           "Microphone:",IDC_MICROPHONE_LABEL,32,178,47,8
 END

src/modules/ZoomIt/ZoomIt/ZoomItSettings.h

@@ -51,6 +51,7 @@ DWORD	g_RecordScalingMP4 = 100;
 RecordingFormat g_RecordingFormat = RecordingFormat::MP4;
 BOOLEAN g_CaptureSystemAudio = TRUE;
 BOOLEAN g_CaptureAudio = FALSE;
+BOOLEAN g_MicMonoMix = FALSE;
 TCHAR	g_MicrophoneDeviceId[MAX_PATH] = {0};
 TCHAR	g_RecordingSaveLocationBuffer[MAX_PATH] = {0};
 TCHAR	g_ScreenshotSaveLocationBuffer[MAX_PATH] = {0};
@@ -99,6 +100,7 @@ REG_SETTING RegSettings[] = {
     { L"RecordScalingMP4", SETTING_TYPE_DWORD, 0, &g_RecordScalingMP4, static_cast<DOUBLE>(g_RecordScalingMP4) },
     { L"CaptureAudio", SETTING_TYPE_BOOLEAN, 0, &g_CaptureAudio, static_cast<DOUBLE>(g_CaptureAudio) },
     { L"CaptureSystemAudio", SETTING_TYPE_BOOLEAN, 0, &g_CaptureSystemAudio, static_cast<DOUBLE>(g_CaptureSystemAudio) },
+    { L"MicMonoMix", SETTING_TYPE_BOOLEAN, 0, &g_MicMonoMix, static_cast<DOUBLE>(g_MicMonoMix) },
     { L"MicrophoneDeviceId", SETTING_TYPE_STRING, sizeof(g_MicrophoneDeviceId), g_MicrophoneDeviceId, static_cast<DOUBLE>(0) },
     { L"RecordingSaveLocation", SETTING_TYPE_STRING, sizeof(g_RecordingSaveLocationBuffer), g_RecordingSaveLocationBuffer, static_cast<DOUBLE>(0) },
     { L"ScreenshotSaveLocation", SETTING_TYPE_STRING, sizeof(g_ScreenshotSaveLocationBuffer), g_ScreenshotSaveLocationBuffer, static_cast<DOUBLE>(0) },

src/modules/ZoomIt/ZoomIt/Zoomit.cpp

@@ -3840,6 +3840,9 @@ INT_PTR CALLBACK OptionsProc( HWND hDlg, UINT message,
         CheckDlgButton( g_OptionsTabs[RECORD_PAGE].hPage, IDC_CAPTURE_AUDIO,
             g_CaptureAudio ? BST_CHECKED: BST_UNCHECKED );
 
+        CheckDlgButton( g_OptionsTabs[RECORD_PAGE].hPage, IDC_MIC_MONO_MIX,
+            g_MicMonoMix ? BST_CHECKED: BST_UNCHECKED );
+
         //
         // The framerate drop down list is not used in the current version (might be added in the future)
         //
@@ -4260,6 +4263,7 @@ INT_PTR CALLBACK OptionsProc( HWND hDlg, UINT message,
             g_ShowExpiredTime = IsDlgButtonChecked(  g_OptionsTabs[BREAK_PAGE].hPage, IDC_CHECK_SHOW_EXPIRED ) == BST_CHECKED;
             g_CaptureSystemAudio = IsDlgButtonChecked(g_OptionsTabs[RECORD_PAGE].hPage, IDC_CAPTURE_SYSTEM_AUDIO) == BST_CHECKED;
             g_CaptureAudio = IsDlgButtonChecked(g_OptionsTabs[RECORD_PAGE].hPage, IDC_CAPTURE_AUDIO) == BST_CHECKED;
+            g_MicMonoMix = IsDlgButtonChecked(g_OptionsTabs[RECORD_PAGE].hPage, IDC_MIC_MONO_MIX) == BST_CHECKED;
             GetDlgItemText( g_OptionsTabs[BREAK_PAGE].hPage, IDC_TIMER, text, 3 );
             text[2] = 0;
             newTimeout = _tstoi( text );
@@ -5605,6 +5609,7 @@ winrt::fire_and_forget StartRecordingAsync( HWND hWnd, LPRECT rcCrop, HWND hWndR
                                         g_RecordFrameRate,
                                         g_CaptureAudio,
                                         g_CaptureSystemAudio,
+                                        g_MicMonoMix,
                                         stream );
 
         recordingStarted = (g_RecordingSession != nullptr);

src/modules/ZoomIt/ZoomIt/resource.h

@@ -111,6 +111,7 @@
 #define IDC_SMOOTH_IMAGE				1107
 #define IDC_CAPTURE_SYSTEM_AUDIO        1108
 #define IDC_MICROPHONE_LABEL            1109
+#define IDC_MIC_MONO_MIX                1110
 #define IDC_SAVE                        40002
 #define IDC_COPY                        40004
 #define IDC_RECORD                      40006

src/settings-ui/Settings.UI.Library/ZoomItProperties.cs

@@ -93,6 +93,8 @@ namespace Microsoft.PowerToys.Settings.UI.Library
 
         public BoolProperty CaptureAudio { get; set; }
 
+        public BoolProperty MicMonoMix { get; set; }
+
         public StringProperty MicrophoneDeviceId { get; set; }
     }
 }

src/settings-ui/Settings.UI/SettingsXAML/Views/ZoomItPage.xaml

@@ -1,4 +1,4 @@
-<local:NavigablePage
+<local:NavigablePage
     x:Class="Microsoft.PowerToys.Settings.UI.Views.ZoomItPage"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
@@ -281,6 +281,12 @@
                             <tkcontrols:SettingsCard Name="ZoomItRecordCaptureAudio" ContentAlignment="Left">
                                 <CheckBox x:Uid="ZoomIt_Record_CaptureAudio" IsChecked="{x:Bind ViewModel.RecordCaptureAudio, Mode=TwoWay}" />
                             </tkcontrols:SettingsCard>
+                            <tkcontrols:SettingsCard Name="ZoomItRecordMicMonoMix" ContentAlignment="Left">
+                                <CheckBox
+                                    x:Uid="ZoomIt_Record_MicMonoMix"
+                                    IsChecked="{x:Bind ViewModel.RecordMicMonoMix, Mode=TwoWay}"
+                                    Visibility="{x:Bind ViewModel.RecordCaptureAudio, Mode=OneWay}" />
+                            </tkcontrols:SettingsCard>
                             <tkcontrols:SettingsCard
                                 Name="ZoomItRecordMicrophone"
                                 x:Uid="ZoomIt_Record_Microphone"

src/settings-ui/Settings.UI/Strings/en-us/Resources.resw

@@ -4718,6 +4718,9 @@ The break timer font matches the text font.</value>
   <data name="ZoomIt_Record_CaptureAudio.Content" xml:space="preserve">
     <value>Capture audio input</value>
   </data>
+  <data name="ZoomIt_Record_MicMonoMix.Content" xml:space="preserve">
+    <value>Mono</value>
+  </data>
   <data name="ZoomIt_Record_Microphone.Header" xml:space="preserve">
     <value>Microphone</value>
   </data>

src/settings-ui/Settings.UI/ViewModels/ZoomItViewModel.cs

@@ -878,6 +878,20 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
             }
         }
 
+        public bool RecordMicMonoMix
+        {
+            get => _zoomItSettings.Properties.MicMonoMix.Value;
+            set
+            {
+                if (_zoomItSettings.Properties.MicMonoMix.Value != value)
+                {
+                    _zoomItSettings.Properties.MicMonoMix.Value = value;
+                    OnPropertyChanged(nameof(RecordMicMonoMix));
+                    NotifySettingsChanged();
+                }
+            }
+        }
+
         public string RecordMicrophoneDeviceId
         {
             get => _zoomItSettings.Properties.MicrophoneDeviceId.Value;