Handle missing Decklink hardware when drivers are installed (#238)

Signed-off-by: xShirae <xshiraayuki@gmail.com>

Author: xShirae

src/plugin/video_output/bmd_decklink/src/decklink_audio_device.cpp

@@ -29,10 +29,16 @@ long DecklinkAudioOutputDevice::desired_samples() {
 }
 
 long DecklinkAudioOutputDevice::latency_microseconds() {
+    if (!bmd_output_) {
+        return 0;
+    }
     return (bmd_output_->num_samples_in_buffer() * 1000000) / sample_rate_;
 }
 
 bool DecklinkAudioOutputDevice::push_samples(const void *sample_data, const long num_samples) {
+    if (!bmd_output_) {
+        return false;
+    }
     bmd_output_->receive_samples_from_xstudio((int16_t *)sample_data, num_samples);
     return true;
-}
+}

src/plugin/video_output/bmd_decklink/src/decklink_output.cpp

@@ -113,7 +113,7 @@ DecklinkOutput::DecklinkOutput(BMDecklinkPlugin *decklink_xstudio_plugin)
       decklink_output_interface_(NULL),
       decklink_xstudio_plugin_(decklink_xstudio_plugin) {
 
-    init_decklink();
+    is_available_ = init_decklink();
 }
 
 DecklinkOutput::~DecklinkOutput() {
@@ -436,6 +436,10 @@ bool DecklinkOutput::start_sdi_output() {
 
     try {
 
+        if (!decklink_output_interface_) {
+            throw std::runtime_error("No DeckLink device is available.");
+        }
+
         bool mode_matched = false;
         // Get first avaliable video mode for Output
         if (decklink_output_interface_->GetDisplayModeIterator(&display_mode_iterator) ==
@@ -532,9 +536,11 @@ bool DecklinkOutput::stop_sdi_output(const std::string &error_message) {
 
     spdlog::info("Stopping Decklink output loop. {}", error_message);
 
-    decklink_output_interface_->StopScheduledPlayback(0, NULL, 0);
-    decklink_output_interface_->DisableVideoOutput();
-    decklink_output_interface_->DisableAudioOutput();
+    if (decklink_output_interface_) {
+        decklink_output_interface_->StopScheduledPlayback(0, NULL, 0);
+        decklink_output_interface_->DisableVideoOutput();
+        decklink_output_interface_->DisableAudioOutput();
+    }
 
     mutex_.lock();
 
@@ -908,6 +914,9 @@ long DecklinkOutput::num_samples_in_buffer() {
     // note this method is called by the xstudio audio output thread
     // Have to assume that GetBufferedAudioSampleFrameCount is not thread safe. BMD SDK
     // does not tell us otherwise
+    if (!decklink_output_interface_) {
+        return 0;
+    }
     std::unique_lock lk0(bmd_mutex_);
     uint32_t prerollAudioSampleCount;
     if (decklink_output_interface_->GetBufferedAudioSampleFrameCount(
@@ -920,6 +929,12 @@ long DecklinkOutput::num_samples_in_buffer() {
 // Note, I have not yet understood the significance of the preroll flag
 void DecklinkOutput::copy_audio_samples_to_decklink_buffer(const bool /*preroll*/) {
 
+    if (!decklink_output_interface_) {
+        fetch_more_samples_from_xstudio_ = true;
+        audio_samples_cv_.notify_one();
+        return;
+    }
+
     std::unique_lock lk0(bmd_mutex_);
 
     // How many samples are sitting on the SDI card ready to be played?

src/plugin/video_output/bmd_decklink/src/decklink_output.hpp

@@ -142,6 +142,8 @@ namespace bm_decklink_plugin_1_0 {
             hdr_metadata_mutex_.unlock();
         }
 
+        [[nodiscard]] bool is_available() const { return is_available_; }
+
       private:
         AVOutputCallback *output_callback_;
         std::mutex mutex_;
@@ -195,6 +197,7 @@ namespace bm_decklink_plugin_1_0 {
 
         HDRMetadata hdr_metadata_;
         std::mutex hdr_metadata_mutex_;
+        bool is_available_ = {false};
     };
 
     class AVOutputCallback : public IDeckLinkVideoOutputCallback,
@@ -234,4 +237,4 @@ namespace bm_decklink_plugin_1_0 {
     };
 
 } // namespace bm_decklink_plugin_1_0
-} // namespace xstudio
+} // namespace xstudio

src/plugin/video_output/bmd_decklink/src/decklink_plugin.cpp

@@ -284,6 +284,9 @@ void BMDecklinkPlugin::attribute_changed(const utility::Uuid &attribute_uuid, co
 
 audio::AudioOutputDevice *
 BMDecklinkPlugin::make_audio_output_device(const utility::JsonStore &prefs) {
+    if (!dcl_output_ || !dcl_output_->is_available()) {
+        return nullptr;
+    }
     return static_cast<audio::AudioOutputDevice *>(
         new DecklinkAudioOutputDevice(prefs, dcl_output_));
 }
@@ -295,6 +298,13 @@ void BMDecklinkPlugin::initialise() {
         dcl_output_ = new DecklinkOutput(this);
         set_hdr_mode_and_metadata();
 
+        if (!dcl_output_->is_available()) {
+            status_message_->set_value("No DeckLink device detected.");
+            is_in_error_->set_value(true);
+            spdlog::warn("Decklink drivers found, but no DeckLink device is available.");
+            return;
+        }
+
         resolutions_->set_role_data(
             module::Attribute::StringChoices, dcl_output_->output_resolution_names());