Attempt to fix screenshots being too old.

Author: Mysticial

SerialPrograms/Source/CommonFramework/VideoPipeline/Backends/CameraWidgetQt6.5.h

@@ -110,8 +110,8 @@ class CameraVideoSource : public QObject, public VideoSource{
     virtual VideoSnapshot snapshot_latest_blocking() override{
         return m_snapshot_manager.snapshot_latest_blocking();
     }
-    virtual VideoSnapshot snapshot_recent_nonblocking() override{
-        return m_snapshot_manager.snapshot_recent_nonblocking();
+    virtual VideoSnapshot snapshot_recent_nonblocking(WallClock min_time) override{
+        return m_snapshot_manager.snapshot_recent_nonblocking(min_time);
     }
 
     virtual QWidget* make_display_QtWidget(QWidget* parent) override;

SerialPrograms/Source/CommonFramework/VideoPipeline/Backends/CameraWidgetQt6.h

@@ -67,8 +67,8 @@ class CameraVideoSource : public QObject, public VideoSource{
     virtual VideoSnapshot snapshot_latest_blocking() override{
         return m_snapshot_manager.snapshot_latest_blocking();
     }
-    virtual VideoSnapshot snapshot_recent_nonblocking() override{
-        return m_snapshot_manager.snapshot_recent_nonblocking();
+    virtual VideoSnapshot snapshot_recent_nonblocking(WallClock min_time) override{
+        return m_snapshot_manager.snapshot_recent_nonblocking(min_time);
     }
 
     virtual QWidget* make_display_QtWidget(QWidget* parent) override;

SerialPrograms/Source/CommonFramework/VideoPipeline/Backends/SnapshotManager.cpp

@@ -197,7 +197,7 @@ VideoSnapshot SnapshotManager::snapshot_latest_blocking(){
     return m_converted_snapshot;
 }
 
-VideoSnapshot SnapshotManager::snapshot_recent_nonblocking(){
+VideoSnapshot SnapshotManager::snapshot_recent_nonblocking(WallClock min_time){
     WallClock now = current_time();
 
     std::lock_guard<std::mutex> lg(m_lock);
@@ -223,7 +223,16 @@ VideoSnapshot SnapshotManager::snapshot_recent_nonblocking(){
 
     //  Cached snapshot isn't too old. Return it.
 
-    std::chrono::milliseconds window(m_stats_conversion.max());
+    if (min_time <= m_converted_snapshot.timestamp){
+//        cout << "snapshot_recent_nonblocking(): Good..." << endl;
+        return m_converted_snapshot;
+    }else{
+//        cout << "snapshot_recent_nonblocking(): Too old..." << endl;
+        return VideoSnapshot();
+    }
+
+#if 0
+    std::chrono::microseconds window(m_stats_conversion.max());
 //    cout << "window = " << window.count() << endl;
 
     WallClock oldest_allowed = now - 2 * window;
@@ -236,6 +245,7 @@ VideoSnapshot SnapshotManager::snapshot_recent_nonblocking(){
 
 //    cout << "snapshot_recent_nonblocking(): Too old..." << endl;
     return VideoSnapshot();
+#endif
 }
 
 

SerialPrograms/Source/CommonFramework/VideoPipeline/Backends/SnapshotManager.h

@@ -25,7 +25,7 @@ class SnapshotManager{
 
 public:
     VideoSnapshot snapshot_latest_blocking();
-    VideoSnapshot snapshot_recent_nonblocking();
+    VideoSnapshot snapshot_recent_nonblocking(WallClock min_time);
 
 private:
     static QImage frame_to_image(const QVideoFrame& frame);

SerialPrograms/Source/CommonFramework/VideoPipeline/VideoFeed.h

@@ -77,14 +77,17 @@ class VideoFeed{
     //  Implementations must be able to handle calls to this at high rate from
     //  many different threads simultaneously. So it should perform caching.
     //
-    virtual VideoSnapshot snapshot() = 0;
+    VideoSnapshot snapshot(){
+        return snapshot_latest_blocking();
+    }
+    virtual VideoSnapshot snapshot_latest_blocking() = 0;
 
     //
     //  This is a non-blocking snapshot function. It will never block, but it
     //  is not guaranteed to return the absolute latest snapshot.
     //
     //  If this returns a null snapshot, it can mean either that the video
-    //  isn't available or that no snapshot is ready to be given right now.
+    //  isn't available or that no snapshot (>= min_time) is ready.
     //
     //  Implementations must be able to handle calls to this at high rate from
     //  many different threads simultaneously. So it should perform caching.
@@ -94,7 +97,7 @@ class VideoFeed{
     //  function will begin prefetch conversions of frames so they are ready
     //  on future calls.
     //
-    virtual VideoSnapshot snapshot_recent_nonblocking() = 0;
+    virtual VideoSnapshot snapshot_recent_nonblocking(WallClock min_time) = 0;
 
 
 public:

SerialPrograms/Source/CommonFramework/VideoPipeline/VideoSession.cpp

@@ -191,18 +191,18 @@ void VideoSession::set_resolution(Resolution resolution){
 }
 
 
-VideoSnapshot VideoSession::snapshot(){
+VideoSnapshot VideoSession::snapshot_latest_blocking(){
     ReadSpinLock lg(m_state_lock);
     if (m_video_source){
         return m_video_source->snapshot_latest_blocking();
     }else{
         return VideoSnapshot();
     }
 }
-VideoSnapshot VideoSession::snapshot_recent_nonblocking(){
+VideoSnapshot VideoSession::snapshot_recent_nonblocking(WallClock min_time){
     ReadSpinLock lg(m_state_lock);
     if (m_video_source){
-        return m_video_source->snapshot_recent_nonblocking();
+        return m_video_source->snapshot_recent_nonblocking(min_time);
     }else{
         return VideoSnapshot();
     }

SerialPrograms/Source/CommonFramework/VideoPipeline/VideoSession.h

@@ -62,8 +62,8 @@ class VideoSession
     Resolution current_resolution();
     std::vector<Resolution> supported_resolutions() const;
 
-    virtual VideoSnapshot snapshot() override;
-    virtual VideoSnapshot snapshot_recent_nonblocking() override;
+    virtual VideoSnapshot snapshot_latest_blocking() override;
+    virtual VideoSnapshot snapshot_recent_nonblocking(WallClock min_time) override;
 
     virtual double fps_source() const override;
     virtual double fps_display() const override;

SerialPrograms/Source/CommonFramework/VideoPipeline/VideoSource.h

@@ -61,7 +61,7 @@ class VideoSource{
     virtual const std::vector<Resolution>& supported_resolutions() const = 0;
 
     virtual VideoSnapshot snapshot_latest_blocking() = 0;
-    virtual VideoSnapshot snapshot_recent_nonblocking() = 0;
+    virtual VideoSnapshot snapshot_recent_nonblocking(WallClock min_time) = 0;
 
 
 protected:

SerialPrograms/Source/CommonFramework/VideoPipeline/VideoSources/VideoSource_StillImage.h

@@ -76,7 +76,7 @@ class VideoSource_StillImage : public VideoSource{
     virtual VideoSnapshot snapshot_latest_blocking() override{
         return m_snapshot;
     }
-    virtual VideoSnapshot snapshot_recent_nonblocking() override{
+    virtual VideoSnapshot snapshot_recent_nonblocking(WallClock min_time) override{
         return m_snapshot;
     }
 

SerialPrograms/Source/CommonTools/InferencePivots/VisualInferencePivot.cpp

@@ -91,7 +91,13 @@ void VisualInferencePivot::run(void* event, bool is_back_to_back) noexcept{
         if (!is_back_to_back || callback.last_timestamp == m_last.timestamp){
 //            cout << "back-to-back" << endl;
 //            m_last = m_feed.snapshot();
-            m_last = m_feed.snapshot_recent_nonblocking();
+
+            WallClock min_time = callback.last_timestamp;
+            if (min_time == WallClock::min()){
+                min_time = current_time() - 2 * callback.period;
+            }
+
+            m_last = m_feed.snapshot_recent_nonblocking(min_time);
         }
 
         if (!m_last){