win-asio: ASIO host for obs-studio

frontend/data/locale/en-US.ini

@@ -1321,6 +1321,8 @@ Basic.Settings.Advanced.Video.HdrNominalPeakLevel="HDR Nominal Peak Level"
 Basic.Settings.Advanced.Audio.MonitoringDevice="Monitoring Device"
 Basic.Settings.Advanced.Audio.MonitoringDevice.Default="Default"
 Basic.Settings.Advanced.Audio.DisableAudioDucking="Disable Windows audio ducking"
+Basic.Settings.Advanced.Audio.AsioMonitoringDevice="ASIO Monitoring Device"
+Basic.Settings.Audio.AsioMonitoring="Setup Panel"
 Basic.Settings.Advanced.StreamDelay="Stream Delay"
 Basic.Settings.Advanced.StreamDelay.Duration="Duration"
 Basic.Settings.Advanced.StreamDelay.Preserve="Preserve cutoff point (increase delay) when reconnecting"

frontend/data/themes/Yami.obt

@@ -1465,6 +1465,12 @@ QPushButton::menu-indicator {
     right: -2px;
 }
 
+QWidget QFormLayout > QToolButton#asioMonitoring {
+  min-width: 0px;
+  max-width: 16777215px;
+  text-align: center;
+}
+
 QToolButton {
     border: 1px solid var(--button_border);
 }

frontend/forms/OBSBasicSettings.ui

@@ -6327,6 +6327,29 @@
                      </property>
                     </widget>
                    </item>
+                   <item row="3" column="0">
+                    <widget class="QLabel" name="asioDeviceLabel">
+                     <property name="text">
+                      <string>Basic.Settings.Advanced.Audio.AsioMonitoringDevice</string>
+                     </property>
+                     <property name="buddy">
+                      <cstring>asioMonitoring</cstring>
+                     </property>
+                    </widget>
+                   </item>
+                   <item row="3" column="1">
+                    <widget class="QToolButton" name="asioMonitoring">
+                     <property name="text">
+                      <string>Basic.Settings.Audio.AsioMonitoring</string>
+                     </property>
+                     <property name="objectName">
+                      <string>asioMonitoring</string>
+                     </property>
+                     <property name="sizePolicy">
+                      <sizepolicy hsizetype="Minimum" vsizetype="Fixed"/>
+                     </property>
+                    </widget>
+                   </item>
                   </layout>
                  </widget>
                 </item>
@@ -8955,6 +8978,7 @@
   <tabstop>meterDecayRate</tabstop>
   <tabstop>peakMeterType</tabstop>
   <tabstop>monitoringDevice</tabstop>
+  <tabstop>asioMonitoring</tabstop>
   <tabstop>disableAudioDucking</tabstop>
   <tabstop>lowLatencyBuffering</tabstop>
   <tabstop>baseResolution</tabstop>

frontend/plugins/CMakeLists.txt

@@ -1,4 +1,5 @@
 add_subdirectory(aja-output-ui)
+add_obs_plugin(asio-output-ui PLATFORMS WINDOWS)
 add_subdirectory(decklink-captions)
 add_subdirectory(decklink-output-ui)
 add_subdirectory(frontend-tools)

frontend/plugins/asio-output-ui/ASIOSettingsDialog.cpp

@@ -0,0 +1,104 @@
+/******************************************************************************
+    Copyright (C) 2022-2025 pkv <[email protected]>
+
+    This file is part of win-asio.
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+
+#include "ASIOSettingsDialog.h"
+#include <util/util.hpp>
+
+extern void output_start();
+extern void output_stop();
+extern bool output_running;
+extern std::string g_currentDeviceName;
+
+ASIOSettingsDialog::ASIOSettingsDialog(QWidget *parent, obs_output_t *output, OBSData settings)
+	: QDialog(parent),
+	  ui(new Ui::Output),
+	  output_(output),
+	  settings_(settings),
+	  currentDeviceName("")
+{
+	ui->setupUi(this);
+	setSizeGripEnabled(true);
+	setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
+	propertiesView = nullptr;
+}
+
+void ASIOSettingsDialog::ShowHideDialog(bool enabled)
+{
+	SetupPropertiesView(enabled);
+	setVisible(!isVisible());
+}
+
+void ASIOSettingsDialog::SetupPropertiesView(bool enabled)
+{
+	if (propertiesView)
+		delete propertiesView;
+
+	propertiesView = new OBSPropertiesView(settings_, "asio_output",
+					       (PropertiesReloadCallback)obs_get_output_properties, 170);
+
+	if (enabled) {
+		ui->propertiesLayout->addWidget(propertiesView);
+		currentDeviceName = g_currentDeviceName;
+	} else {
+		QLabel *noAsioLabel = new QLabel(obs_module_text("AsioOutput.Disabled"), this);
+		noAsioLabel->setWordWrap(true);
+		noAsioLabel->setAlignment(Qt::AlignCenter);
+		ui->propertiesLayout->addWidget(noAsioLabel);
+		adjustSize();
+	}
+
+	connect(propertiesView, &OBSPropertiesView::Changed, this, &ASIOSettingsDialog::PropertiesChanged);
+}
+
+void ASIOSettingsDialog::SaveSettings()
+{
+	BPtr<char> modulePath = obs_module_get_config_path(obs_current_module(), "");
+	os_mkdirs(modulePath);
+	BPtr<char> path = obs_module_get_config_path(obs_current_module(), "asioOutputProps.json");
+	obs_data_t *settings = propertiesView->GetSettings();
+
+	if (settings)
+		obs_data_save_json_safe(settings, path, "tmp", "bak");
+}
+
+void ASIOSettingsDialog::PropertiesChanged()
+{
+	obs_output_update(output_, settings_);
+	SaveSettings();
+	const char *dev = obs_data_get_string(settings_, "device_name");
+	const std::string newDevice = (dev && *dev) ? dev : std::string{};
+
+	const bool wasEmpty = currentDeviceName.empty();
+	const bool nowEmpty = newDevice.empty();
+
+	if (wasEmpty && !nowEmpty) {
+		// No device swapped to a valid device: start if not running
+		if (!output_running)
+			output_start();
+	} else if (!wasEmpty && nowEmpty) {
+		// valid device swapped to None: stop if running
+		if (output_running)
+			output_stop();
+	} else if (!nowEmpty && newDevice != currentDeviceName) {
+		// output was already started so do nothing ...
+	}
+
+	currentDeviceName = newDevice;
+	g_currentDeviceName = newDevice;
+}

frontend/plugins/asio-output-ui/ASIOSettingsDialog.h

@@ -0,0 +1,58 @@
+/******************************************************************************
+    Copyright (C) 2022-2025 pkv <[email protected]>
+
+    This file is part of win-asio.
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+#ifdef __cplusplus
+#define EXPORT_C extern "C"
+#else
+#define EXPORT_C
+#endif
+
+#pragma once
+#include <obs-module.h>
+#include <obs-frontend-api.h>
+#include <obs.hpp>
+#include <properties-view.hpp>
+
+#include <QDialog>
+#include <QAction>
+#include <QMainWindow>
+#include <QLabel>
+
+#include "./forms/ui_output.h"
+
+#include <util/platform.h>
+
+class ASIOSettingsDialog : public QDialog {
+	Q_OBJECT
+
+public:
+	explicit ASIOSettingsDialog(QWidget *parent = 0, obs_output_t *output = nullptr, OBSData settings = nullptr);
+	std::unique_ptr<Ui_Output> ui;
+	void ShowHideDialog(bool enabled);
+	void SetupPropertiesView(bool enabled);
+	void SaveSettings();
+	OBSData settings_;
+	obs_output_t *output_;
+	std::string currentDeviceName;
+
+public slots:
+	void PropertiesChanged();
+
+private:
+	OBSPropertiesView *propertiesView;
+};

frontend/plugins/asio-output-ui/CMakeLists.txt

@@ -0,0 +1,27 @@
+cmake_minimum_required(VERSION 3.28...3.30)
+
+find_package(Qt6 REQUIRED Widgets)
+
+add_library(asio-output-ui MODULE)
+add_library(OBS::asio-output-ui ALIAS asio-output-ui)
+
+target_sources(asio-output-ui PRIVATE asio-ui-main.cpp ASIOSettingsDialog.cpp ASIOSettingsDialog.h)
+
+target_sources(asio-output-ui PRIVATE forms/output.ui)
+
+target_link_libraries(asio-output-ui PRIVATE OBS::libobs OBS::frontend-api OBS::properties-view Qt::Widgets)
+
+configure_file(cmake/windows/obs-module.rc.in asio-output-ui.rc)
+target_sources(asio-output-ui PRIVATE asio-output-ui.rc)
+
+set_property(TARGET asio-output-ui APPEND PROPERTY AUTORCC_OPTIONS --format-version 1)
+
+set_target_properties_obs(
+  asio-output-ui
+  PROPERTIES FOLDER frontend
+             PREFIX ""
+             AUTOMOC ON
+             AUTOUIC ON
+             AUTORCC ON
+             AUTOUIC_SEARCH_PATHS forms
+)