set maximum FPS for webcams

easyopencv/src/main/java/org/openftc/easyopencv/OpenCvWebcam.java

@@ -58,6 +58,13 @@ enum StreamFormat
      */
     void startStreaming(int width, int height, OpenCvCameraRotation rotation, StreamFormat streamFormat);
 
+    /**
+     * Same as {@link #startStreaming(int, int, OpenCvCameraRotation)} except for
+     * @param streamFormat indicates the desired stream format and
+     * @param maxFps indicates the maximum fps.
+     */
+    void startStreaming(int width, int height, OpenCvCameraRotation rotation, StreamFormat streamFormat, int maxFps);
+
     /***
      * Gets the {@link ExposureControl} for this webcam.
      * Please see that interface's javadoc for how to use

easyopencv/src/main/java/org/openftc/easyopencv/OpenCvWebcamImpl.java

@@ -259,7 +259,13 @@ public void startStreaming(int width, int height)
     @Override
     public void startStreaming(int width, int height, OpenCvCameraRotation rotation)
     {
-        startStreaming(width, height, rotation, null);
+        startStreaming(width, height, rotation, null, 0);
+    }
+
+    @Override
+    public void startStreaming(final int width, final int height, OpenCvCameraRotation rotation, StreamFormat streamFormat)
+    {
+        startStreaming(width, height, rotation, streamFormat, 0);
     }
 
     private static int streamFormat2ImageFormat(StreamFormat streamFormat)
@@ -302,9 +308,22 @@ private static String getSizeAndFpsListForFormat(CameraCharacteristics character
         return areAnySupported ? builder.toString() : "NONE";
     }
 
+    /***
+     * Set a specific number of frames per second the image sensor should capture.
+     *
+     * Note that your pipeline may not be fast enough to keep up with what you ask the sensor
+     * to send, which will result in your pipeline FPS not matching what you set here.
+     *
+     * For instance, suppose you request 24FPS, but your pipeline requires an amount of
+     * compute time that results in it only being able to run at 15FPS. In that case, your
+     * pipeline will still run at 15FPS.
+     *
+     * Conversely, if your pipeline is capable of processing 100 frames per second, but
+     * you request only 15FPS from the sensor, your pipeline will run at 15FPS.
+     *
+     */
     @SuppressLint("DefaultLocale")
-    @Override
-    public void startStreaming(final int width, final int height, OpenCvCameraRotation rotation, StreamFormat streamFormat)
+    public void startStreaming(final int width, final int height, OpenCvCameraRotation rotation, StreamFormat streamFormat, final int maxFps)
     {
         boolean userExplicitlyRequestedFormat = streamFormat != null;
 
@@ -380,6 +399,7 @@ public void onConfigured( CameraCaptureSession session)
                         try
                         {
                             int fps = cameraCharacteristics.getMaxFramesPerSecond(format, size);
+                            if (maxFps > 0 && maxFps < fps) fps = maxFps;
 
                             //Indicate how we want to stream
                             final CameraCaptureRequest cameraCaptureRequest = camera.createCaptureRequest(format, size, fps);

examples/src/main/java/org/firstinspires/ftc/teamcode/WebcamExample.java

@@ -97,7 +97,7 @@ public void onOpened()
                  * For a rear facing camera or a webcam, rotation is defined assuming the camera is facing
                  * away from the user.
                  */
-                webcam.startStreaming(320, 240, OpenCvCameraRotation.UPRIGHT);
+                webcam.startStreaming(960, 600, OpenCvCameraRotation.UPRIGHT, OpenCvWebcam.StreamFormat.YUY2, 30);
             }
 
             @Override