Add support to update image only when there is a new frame

README.md

@@ -53,30 +53,39 @@ public class TestDriver extends Application {
         root.getChildren().add(imageView);
 
         Webcam.getWebcams().stream()
-            .findFirst()
+                .findFirst()
-            .ifPresent((final Webcam camera) -> {
+                .ifPresent((final Webcam camera) -> {
-                final WebcamDevice device = camera.getDevice();
+                    final WebcamDevice device = camera.getDevice();
-                LOG.info("Found camera: {}, device = {}", camera, device);
+                    LOG.info("Found camera: {}, device = {}", camera, device);
 
-                final int width = device.getResolution().width;
+                    final int width = device.getResolution().width;
-                final int height = device.getResolution().height;
+                    final int height = device.getResolution().height;
-                final WritableImage fxImage = new WritableImage(width, height);
+                    final WritableImage fxImage = new WritableImage(width, height);
-                Platform.runLater(() -> {
+                    Platform.runLater(() -> {
-                    imageView.setImage(fxImage);
+                        imageView.setImage(fxImage);
-                    stage.setWidth(width);
+                        stage.setWidth(width);
-                    stage.setHeight(height);
+                        stage.setHeight(height);
-                    stage.centerOnScreen();
+                        stage.centerOnScreen();
+                    });
+
+                    camera.getLock().disable();
+                    camera.open();
+                    if (device instanceof WebcamDeviceWithBufferOperations) {
+                        final WebcamDeviceWithBufferOperations dev = ((WebcamDeviceWithBufferOperations) device);
+                        EXECUTOR.scheduleAtFixedRate(new Runnable() {
+                            private long lastFrameTimestamp = -1;
+
+                            @Override
+                            public void run() {
+                                if (dev.updateFXIMage(fxImage, lastFrameTimestamp)) {
+                                    lastFrameTimestamp = dev.getLastFrameTimestamp();
+                                }
+
+                            }
+                        }, 0, 16, TimeUnit.MILLISECONDS);
+                    }
                 });
 
-                camera.getLock().disable();
-                camera.open();
-                if (device instanceof WebcamDeviceWithBufferOperations) {
-                    EXECUTOR.scheduleAtFixedRate(() -> {
-                        ((WebcamDeviceWithBufferOperations) device).updateFXIMage(fxImage);
-                    }, 0, 16, TimeUnit.MILLISECONDS);
-                }
-            });
-
         stage.setOnCloseRequest(t -> {
             Platform.exit();
             System.exit(0);
@@ -89,7 +98,6 @@ public class TestDriver extends Application {
         stage.show();
     }
 }
-
 ```
 
 # Future work

src/main/java/com/github/eduramiba/webcamcapture/TestDriver.java

@@ -54,8 +54,17 @@ public class TestDriver extends Application {
                     camera.getLock().disable();
                     camera.open();
                     if (device instanceof WebcamDeviceWithBufferOperations) {
-                        EXECUTOR.scheduleAtFixedRate(() -> {
+                        final WebcamDeviceWithBufferOperations dev = ((WebcamDeviceWithBufferOperations) device);
-                            ((WebcamDeviceWithBufferOperations) device).updateFXIMage(fxImage);
+                        EXECUTOR.scheduleAtFixedRate(new Runnable() {
+                            private long lastFrameTimestamp = -1;
+
+                            @Override
+                            public void run() {
+                                if (dev.updateFXIMage(fxImage, lastFrameTimestamp)) {
+                                    lastFrameTimestamp = dev.getLastFrameTimestamp();
+                                }
+
+                            }
                         }, 0, 16, TimeUnit.MILLISECONDS);
                     }
                 });

src/main/java/com/github/eduramiba/webcamcapture/drivers/WebcamDeviceWithBufferOperations.java

@@ -7,9 +7,11 @@ import javafx.scene.image.WritableImage;
 
 public interface WebcamDeviceWithBufferOperations extends WebcamDevice {
 
-    BufferedImage getImage(final ByteBuffer byteBuffer);
+    BufferedImage getImage(ByteBuffer byteBuffer);
 
-    boolean updateFXIMage(final WritableImage writableImage, final ByteBuffer byteBuffer);
+    boolean updateFXIMage(WritableImage writableImage);
 
-    boolean updateFXIMage(final WritableImage writableImage);
+    boolean updateFXIMage(WritableImage writableImage, long lastFrameTimestamp);
+
+    long getLastFrameTimestamp();
 }

src/main/java/com/github/eduramiba/webcamcapture/drivers/avfoundation/driver/AVFVideoDevice.java

@@ -36,6 +36,7 @@ public class AVFVideoDevice implements WebcamDevice, WebcamDevice.FPSSource, Web
     private ByteBuffer imgBuffer = null;
     private byte[] arrayByteBuffer = null;
     private BufferedImage bufferedImage = null;
+    private long lastFrameTimestamp = -1;
 
     public AVFVideoDevice(final int deviceIndex, final String id, final String name, final Collection<Dimension> resolutions) {
         this.deviceIndex = deviceIndex;
@@ -159,6 +160,11 @@ public class AVFVideoDevice implements WebcamDevice, WebcamDevice.FPSSource, Web
         return open;
     }
 
+    @Override
+    public long getLastFrameTimestamp() {
+        return lastFrameTimestamp;
+    }
+
     public static final int MAX_FPS = 30;
 
     @Override
@@ -217,18 +223,23 @@ public class AVFVideoDevice implements WebcamDevice, WebcamDevice.FPSSource, Web
     }
 
     @Override
-    public synchronized boolean updateFXIMage(WritableImage writableImage) {
+    public boolean updateFXIMage(WritableImage writableImage) {
+        return updateFXIMage(writableImage, -1);
+    }
+
+    @Override
+    public synchronized boolean updateFXIMage(final WritableImage writableImage, final long lastFrameTimestamp) {
+        return updateFXIMage(writableImage, imgBuffer, lastFrameTimestamp);
+    }
+
+    private boolean updateFXIMage(final WritableImage writableImage, final ByteBuffer byteBuffer, final long lastFrameTimestamp) {
         if (!isOpen()) {
             return false;
         }
 
         updateBuffer();
 
-        return updateFXIMage(writableImage, imgBuffer);
+        if (this.lastFrameTimestamp <= lastFrameTimestamp) {
-    }
-
-    public boolean updateFXIMage(final WritableImage writableImage, final ByteBuffer byteBuffer) {
-        if (!isOpen()) {
             return false;
         }
 
@@ -249,9 +260,11 @@ public class AVFVideoDevice implements WebcamDevice, WebcamDevice.FPSSource, Web
 
     private void updateBuffer() {
         if (LibVideoCapture.INSTANCE.vcavf_has_new_frame(deviceIndex)) {
-            LibVideoCapture.INSTANCE.vcavf_grab_frame(
+            if (LibVideoCapture.INSTANCE.vcavf_grab_frame(
                 deviceIndex,
-                Native.getDirectBufferPointer(imgBuffer), imgBuffer.capacity());
+                Native.getDirectBufferPointer(imgBuffer), imgBuffer.capacity())) {
+                lastFrameTimestamp = System.currentTimeMillis();
+            };
         }
     }
 

src/main/java/com/github/eduramiba/webcamcapture/drivers/capturemanager/CaptureManagerFrameGrabberSession.java

@@ -37,6 +37,7 @@ public class CaptureManagerFrameGrabberSession {
     private int videoWidth = -1;
     private int videoHeight = -1;
     private int bufferSizeBytes = -1;
+    private long lastFrameTimestamp = -1;
 
     public boolean init(
             final CaptureManagerSource source,
@@ -223,6 +224,10 @@ public class CaptureManagerFrameGrabberSession {
         session.closeSession();
     }
 
+    public long getLastFrameTimestamp() {
+        return lastFrameTimestamp;
+    }
+
     public synchronized BufferedImage toBufferedImage() {
         if (!isOpen()) {
             return null;
@@ -249,7 +254,7 @@ public class CaptureManagerFrameGrabberSession {
         return bufferedImage;
     }
 
-    public synchronized boolean updateFXIMage(final WritableImage writableImage) {
+    public synchronized boolean updateFXIMage(final WritableImage writableImage, long lastFrameTimestamp) {
         if (!isOpen()) {
             return false;
         }
@@ -260,6 +265,10 @@ public class CaptureManagerFrameGrabberSession {
             return false;
         }
 
+        if (this.lastFrameTimestamp <= lastFrameTimestamp) {
+            return false;
+        }
+
         updateFXIMage(writableImage, directBuffer);
 
         return true;
@@ -285,7 +294,12 @@ public class CaptureManagerFrameGrabberSession {
 
 
     public synchronized int updateDirectBuffer() {
-        return sampleGrabberCall.readData(directBuffer);
+        final int readSize = sampleGrabberCall.readData(directBuffer);
+        if (readSize > 0) {
+            lastFrameTimestamp = System.currentTimeMillis();
+        }
+
+        return readSize;
     }
 
     public boolean isOpen() {

src/main/java/com/github/eduramiba/webcamcapture/drivers/capturemanager/CaptureManagerVideoDevice.java

@@ -144,6 +144,15 @@ public class CaptureManagerVideoDevice implements WebcamDevice, WebcamDevice.FPS
         return session != null && session.isOpen();
     }
 
+    @Override
+    public long getLastFrameTimestamp() {
+        if (isOpen()) {
+            return session.getLastFrameTimestamp();
+        }
+
+        return -1;
+    }
+
     private static Pair<CaptureManagerStreamDescriptor, CaptureManagerMediaType> findBestMediaTypeInStreams(
             final Collection<CaptureManagerStreamDescriptor> videoStreams,
             final Dimension resolution
@@ -231,9 +240,9 @@ public class CaptureManagerVideoDevice implements WebcamDevice, WebcamDevice.FPS
     }
 
     @Override
-    public boolean updateFXIMage(WritableImage writableImage, ByteBuffer byteBuffer) {
+    public boolean updateFXIMage(final WritableImage writableImage, final long lastFrameTimestamp) {
         if (isOpen()) {
-            session.updateFXIMage(writableImage, byteBuffer);
+            session.updateFXIMage(writableImage, lastFrameTimestamp);
             return true;
         }
 
@@ -242,11 +251,7 @@ public class CaptureManagerVideoDevice implements WebcamDevice, WebcamDevice.FPS
 
     @Override
     public boolean updateFXIMage(WritableImage writableImage) {
-        if (isOpen()) {
+        return updateFXIMage(writableImage, -1);
-            return session.updateFXIMage(writableImage);
-        }
-
-        return false;
     }
 
     @Override