obs-webrtc: Add WebRTC Simulcast Support

UI/data/locale/en-US.ini

@@ -1011,6 +1011,7 @@ Basic.Settings.Output.RetryDelay="Retry Delay"
 Basic.Settings.Output.MaxRetries="Maximum Retries"
 Basic.Settings.Output.Advanced="Enable Custom Encoder Settings (Advanced)"
 Basic.Settings.Output.EncoderPreset="Encoder Preset"
+Basic.Settings.Output.Simulcast="Enable Simulcast"
 Basic.Settings.Output.EncoderPreset.ultrafast="%1 (low CPU usage, lowest quality)"
 Basic.Settings.Output.EncoderPreset.veryfast="%1 (default) (medium CPU usage, standard quality)"
 Basic.Settings.Output.EncoderPreset.fast="%1 (high CPU usage, high quality)"
@@ -1019,6 +1020,7 @@ Basic.Settings.Output.CustomMuxerSettings="Custom Muxer Settings"
 Basic.Settings.Output.NoSpaceFileName="Generate File Name without Space"
 
 # basic mode 'output' settings - advanced section
+Basic.Settings.Output.Adv.Simulcast="Enable Simulcast"
 Basic.Settings.Output.Adv.Rescale="Rescale Output"
 Basic.Settings.Output.Adv.AudioTrack="Audio Track"
 Basic.Settings.Output.Adv.Streaming="Streaming"

UI/forms/OBSBasicSettings.ui

@@ -1766,7 +1766,7 @@
                           <bool>true</bool>
                          </property>
                         </widget>
-                       </item>
+		       </item>
                        <item row="5" column="0">
                         <widget class="QLabel" name="label_23">
                          <property name="text">
@@ -1776,11 +1776,21 @@
                           <cstring>simpleOutCustom</cstring>
                          </property>
                         </widget>
-                       </item>
+		       </item>
                        <item row="5" column="1">
                         <widget class="QLineEdit" name="simpleOutCustom"/>
                        </item>
-                       <item row="6" column="0">
+                       <item row="6" column="1">
+                        <widget class="QCheckBox" name="simpleOutSimulcast">
+                         <property name="text">
+                          <string>Basic.Settings.Output.Simulcast</string>
+                         </property>
+                         <property name="checked">
+                          <bool>false</bool>
+                         </property>
+                        </widget>
+                       </item>
+		       <item row="7" column="0">
                         <widget class="QLabel" name="simpleOutStrAEncoderLabel">
                          <property name="text">
                           <string>Basic.Settings.Output.Encoder.Audio</string>
@@ -1790,7 +1800,7 @@
                          </property>
                         </widget>
                        </item>
-                       <item row="6" column="1">
+                       <item row="7" column="1">
                         <widget class="QComboBox" name="simpleOutStrAEncoder"/>
                        </item>
                       </layout>
@@ -2524,7 +2534,17 @@
                            <item row="3" column="1">
                             <widget class="QComboBox" name="advOutEncoder"/>
                            </item>
-                           <item row="4" column="0">
+                           <item row="4" column="1">
+                            <widget class="QCheckBox" name="advOutUseSimulcast">
+                             <property name="text">
+                              <string>Basic.Settings.Output.Adv.Simulcast</string>
+                             </property>
+                             <property name="checked">
+                              <bool>false</bool>
+                             </property>
+                            </widget>
+                           </item>
+			   <item row="5" column="0">
                             <widget class="QCheckBox" name="advOutUseRescale">
                              <property name="sizePolicy">
                               <sizepolicy hsizetype="Minimum" vsizetype="Expanding">
@@ -2540,7 +2560,7 @@
                              </property>
                             </widget>
                            </item>
-                           <item row="4" column="1">
+                           <item row="5" column="1">
                             <widget class="QComboBox" name="advOutRescale">
                              <property name="enabled">
                               <bool>false</bool>

UI/window-basic-main-outputs.cpp

@@ -542,6 +542,10 @@ void SimpleOutput::LoadStreamingPreset_Lossy(const char *encoderId)
 	if (!videoStreaming)
 		throw "Failed to create video streaming encoder (simple output)";
 	obs_encoder_release(videoStreaming);
+
+	if (config_get_bool(main->Config(), "SimpleOutput", "UseSimulcast")) {
+		CreateSimulcastEncoders(encoderId);
+	}
 }
 
 /* mistakes have been made to lead us to this. */
@@ -838,9 +842,14 @@ void SimpleOutput::Update()
 	default:
 		obs_encoder_set_preferred_video_format(videoStreaming,
 						       VIDEO_FORMAT_NV12);
+		for (auto enc : simulcastEncoders)
+			obs_encoder_set_preferred_video_format(
+				enc, VIDEO_FORMAT_NV12);
 	}
 
 	obs_encoder_update(videoStreaming, videoSettings);
+	ConfigureSimulcastEncoders(videoSettings, videoBitrate);
+
 	obs_encoder_update(audioStreaming, audioSettings);
 	obs_encoder_update(audioArchive, audioSettings);
 }
@@ -1039,6 +1048,9 @@ inline void SimpleOutput::SetupOutputs()
 {
 	SimpleOutput::Update();
 	obs_encoder_set_video(videoStreaming, obs_get_video());
+	for (auto enc : simulcastEncoders)
+		obs_encoder_set_video(enc, obs_get_video());
+
 	obs_encoder_set_audio(audioStreaming, obs_get_audio());
 	obs_encoder_set_audio(audioArchive, obs_get_audio());
 	int tracks =
@@ -1135,7 +1147,11 @@ bool SimpleOutput::SetupStreaming(obs_service_t *service)
 		outputType = type;
 	}
 
-	obs_output_set_video_encoder(streamOutput, videoStreaming);
+	obs_output_set_video_encoder2(streamOutput, videoStreaming, 0);
+	for (size_t i = 0; i < simulcastEncoders.size(); i++)
+		obs_output_set_video_encoder2(streamOutput,
+					      simulcastEncoders[i], i + 1);
+
 	obs_output_set_audio_encoder(streamOutput, audioStreaming, 0);
 	obs_output_set_service(streamOutput, service);
 	return true;
@@ -2433,6 +2449,56 @@ std::string BasicOutputHandler::GetRecordingFilename(
 	return dst;
 }
 
+void BasicOutputHandler::CreateSimulcastEncoders(const char *encoderId)
+{
+	std::string encoder_name = "simulcast_0";
+	for (auto i = 0; i < 2; i++) {
+		encoder_name[encoder_name.size() - 1] = to_string(i).at(0);
+		auto simulcast_encoder = obs_video_encoder_create(
+			encoderId, encoder_name.c_str(), nullptr, nullptr);
+
+		if (simulcast_encoder) {
+			simulcastEncoders.push_back(simulcast_encoder);
+			obs_encoder_release(simulcast_encoder);
+		} else {
+			blog(LOG_WARNING,
+			     "Failed to create video streaming simulcast encoders (simple output)");
+		}
+	}
+}
+
+void BasicOutputHandler::ConfigureSimulcastEncoders(obs_data_t *videoSettings,
+						    int videoBitrate)
+{
+	video_t *video = obs_get_video();
+
+	if (simulcastEncoders.size() > 0) {
+		uint32_t width = video_output_get_width(video) / 1.5;
+		width -= width % 2;
+
+		uint32_t height = video_output_get_height(video) / 1.5;
+		height -= height % 2;
+
+		obs_data_set_int(videoSettings, "bitrate", videoBitrate / 2);
+		obs_encoder_update(simulcastEncoders[0], videoSettings);
+		obs_encoder_set_scaled_size(simulcastEncoders[0], width,
+					    height);
+	}
+
+	if (simulcastEncoders.size() > 1) {
+		uint32_t width = video_output_get_width(video) / 2;
+		width -= width % 2;
+
+		uint32_t height = video_output_get_height(video) / 2;
+		height -= height % 2;
+
+		obs_data_set_int(videoSettings, "bitrate", videoBitrate / 4);
+		obs_encoder_update(simulcastEncoders[1], videoSettings);
+		obs_encoder_set_scaled_size(simulcastEncoders[1], width,
+					    height);
+	}
+}
+
 BasicOutputHandler *CreateSimpleOutputHandler(OBSBasic *main)
 {
 	return new SimpleOutput(main);

UI/window-basic-main-outputs.hpp

@@ -21,6 +21,8 @@ struct BasicOutputHandler {
 	obs_scene_t *vCamSourceScene = nullptr;
 	obs_sceneitem_t *vCamSourceSceneItem = nullptr;
 
+	std::vector<OBSEncoder> simulcastEncoders;
+
 	std::string outputType;
 	std::string lastError;
 
@@ -79,6 +81,10 @@ struct BasicOutputHandler {
 					 const char *container, bool noSpace,
 					 bool overwrite, const char *format,
 					 bool ffmpeg);
+
+	void CreateSimulcastEncoders(const char *encoderId);
+	void ConfigureSimulcastEncoders(obs_data_t *videoSettings,
+					int videoBitrate);
 };
 
 BasicOutputHandler *CreateSimpleOutputHandler(OBSBasic *main);

UI/window-basic-settings-stream.cpp

@@ -505,6 +505,14 @@ void OBSBasicSettings::on_service_currentIndexChanged(int idx)
 		if (idx == 0)
 			lastCustomServer = ui->customServer->text();
 	}
+
+	if (IsWHIP()) {
+		ui->simpleOutSimulcast->show();
+		ui->advOutUseSimulcast->show();
+	} else {
+		ui->simpleOutSimulcast->hide();
+		ui->advOutUseSimulcast->hide();
+	}
 }
 
 void OBSBasicSettings::on_customServer_textChanged(const QString &)

UI/window-basic-settings.cpp

@@ -491,6 +491,7 @@ OBSBasicSettings::OBSBasicSettings(QWidget *parent)
 	HookWidget(ui->simpleOutAdvanced,    CHECK_CHANGED,  OUTPUTS_CHANGED);
 	HookWidget(ui->simpleOutPreset,      COMBO_CHANGED,  OUTPUTS_CHANGED);
 	HookWidget(ui->simpleOutCustom,      EDIT_CHANGED,   OUTPUTS_CHANGED);
+	HookWidget(ui->simpleOutSimulcast,   CHECK_CHANGED,  OUTPUTS_CHANGED);
 	HookWidget(ui->simpleOutRecQuality,  COMBO_CHANGED,  OUTPUTS_CHANGED);
 	HookWidget(ui->simpleOutRecEncoder,  COMBO_CHANGED,  OUTPUTS_CHANGED);
 	HookWidget(ui->simpleOutRecAEncoder, COMBO_CHANGED,  OUTPUTS_CHANGED);
@@ -506,6 +507,7 @@ OBSBasicSettings::OBSBasicSettings(QWidget *parent)
 	HookWidget(ui->simpleRBMegsMax,      SCROLL_CHANGED, OUTPUTS_CHANGED);
 	HookWidget(ui->advOutEncoder,        COMBO_CHANGED,  OUTPUTS_CHANGED);
 	HookWidget(ui->advOutAEncoder,       COMBO_CHANGED,  OUTPUTS_CHANGED);
+	HookWidget(ui->advOutUseSimulcast,   CHECK_CHANGED,  OUTPUTS_CHANGED);
 	HookWidget(ui->advOutUseRescale,     CHECK_CHANGED,  OUTPUTS_CHANGED);
 	HookWidget(ui->advOutRescale,        CBEDIT_CHANGED, OUTPUTS_CHANGED);
 	HookWidget(ui->advOutTrack1,         CHECK_CHANGED,  OUTPUTS_CHANGED);
@@ -1927,6 +1929,8 @@ void OBSBasicSettings::LoadSimpleOutputSettings()
 		config_get_uint(main->Config(), "SimpleOutput", "ABitrate");
 	bool advanced =
 		config_get_bool(main->Config(), "SimpleOutput", "UseAdvanced");
+	bool simulcast =
+		config_get_bool(main->Config(), "SimpleOutput", "UseSimulcast");
 	const char *preset =
 		config_get_string(main->Config(), "SimpleOutput", "Preset");
 	const char *qsvPreset =
@@ -1996,6 +2000,15 @@ void OBSBasicSettings::LoadSimpleOutputSettings()
 	ui->simpleOutAdvanced->setChecked(advanced);
 	ui->simpleOutCustom->setText(custom);
 
+	OBSService service = GetStream1Service();
+	if (strcmp(obs_service_get_id(service), "whip_custom") == 0) {
+		ui->simpleOutSimulcast->show();
+	} else {
+		ui->simpleOutSimulcast->hide();
+	}
+
+	ui->simpleOutSimulcast->setChecked(simulcast);
+
 	idx = ui->simpleOutRecQuality->findData(QString(recQual));
 	if (idx == -1)
 		idx = 0;
@@ -2075,11 +2088,13 @@ static inline QString makeFormatToolTip()
 
 void OBSBasicSettings::LoadAdvOutputStreamingSettings()
 {
+	bool simulcast = config_get_bool(main->Config(), "AdvOut", "Simulcast");
 	bool rescale = config_get_bool(main->Config(), "AdvOut", "Rescale");
 	const char *rescaleRes =
 		config_get_string(main->Config(), "AdvOut", "RescaleRes");
 	int trackIndex = config_get_int(main->Config(), "AdvOut", "TrackIndex");
 
+	ui->advOutUseSimulcast->setChecked(simulcast);
 	ui->advOutUseRescale->setChecked(rescale);
 	ui->advOutRescale->setEnabled(rescale);
 	ui->advOutRescale->setCurrentText(rescaleRes);
@@ -3845,6 +3860,7 @@ void OBSBasicSettings::SaveOutputSettings()
 	SaveCheckBox(ui->simpleOutAdvanced, "SimpleOutput", "UseAdvanced");
 	SaveComboData(ui->simpleOutPreset, "SimpleOutput", presetType);
 	SaveEdit(ui->simpleOutCustom, "SimpleOutput", "x264Settings");
+	SaveCheckBox(ui->simpleOutSimulcast, "SimpleOutput", "UseSimulcast");
 	SaveComboData(ui->simpleOutRecQuality, "SimpleOutput", "RecQuality");
 	SaveComboData(ui->simpleOutRecEncoder, "SimpleOutput", "RecEncoder");
 	SaveComboData(ui->simpleOutRecAEncoder, "SimpleOutput",
@@ -3860,6 +3876,7 @@ void OBSBasicSettings::SaveOutputSettings()
 
 	SaveComboData(ui->advOutEncoder, "AdvOut", "Encoder");
 	SaveComboData(ui->advOutAEncoder, "AdvOut", "AudioEncoder");
+	SaveCheckBox(ui->advOutUseSimulcast, "AdvOut", "Simulcast");
 	SaveCheckBox(ui->advOutUseRescale, "AdvOut", "Rescale");
 	SaveCombo(ui->advOutRescale, "AdvOut", "RescaleRes");
 	SaveTrackIndex(main->Config(), "AdvOut", "TrackIndex", ui->advOutTrack1,
@@ -4373,6 +4390,7 @@ void OBSBasicSettings::on_advOutEncoder_currentIndexChanged()
 		ui->advOutEncoderLayout->addWidget(streamEncoderProps);
 	}
 
+	ui->advOutUseSimulcast->setVisible(true);
 	ui->advOutUseRescale->setVisible(true);
 	ui->advOutRescale->setVisible(true);
 }