使用OpenCV Android教程我想更改预览分辨率。因此，我注释掉了calcPreviewSize函数，并将resoultion设置为640x480，支持并包含在相机特性中。预览分辨率的更改是成功的，但是应用程序崩溃，尽管给定的行不包含官方教程中的任何更改。
E/JavaCamera2View: createCaptureSession failed
java.lang.IllegalStateException: Session has been closed; further changes are illegal.
at android.hardware.camera2.impl.CameraCaptureSessionImpl.checkNotClosed(CameraCaptureSessionImpl.java:607)
at android.hardware.camera2.impl.CameraCaptureSessionImpl.setRepeatingRequest(CameraCaptureSessionImpl.java:227)
at org.opencv.android.JavaCamera2View$3.onConfigured(JavaCamera2View.java:220)
at java.lang.reflect.Method.invoke(Native Method)
public class JavaCamera2View extends CameraBridgeViewBase {
private static final String LOGTAG = "JavaCamera2View";
private ImageReader mImageReader;
private int mPreviewFormat = ImageFormat.YUV_420_888;
public int widthP = 640;
public int heightP = 480;
public CameraDevice mCameraDevice;
private CameraCaptureSession mCaptureSession;
private CaptureRequest.Builder mPreviewRequestBuilder;
private String mCameraID;
private android.util.Size mPreviewSize = new android.util.Size(-1, -1);
private HandlerThread mBackgroundThread;
private Handler mBackgroundHandler;
public JavaCamera2View(Context context, int cameraId) {
super(context, cameraId);
}
public JavaCamera2View(Context context, AttributeSet attrs) {
super(context, attrs);
}
private void startBackgroundThread() {
Log.i(LOGTAG, "startBackgroundThread");
stopBackgroundThread();
mBackgroundThread = new HandlerThread("OpenCVCameraBackground");
mBackgroundThread.start();
mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
}
private void stopBackgroundThread() {
Log.i(LOGTAG, "stopBackgroundThread");
if (mBackgroundThread == null)
return;
mBackgroundThread.quitSafely();
try {
mBackgroundThread.join();
mBackgroundThread = null;
mBackgroundHandler = null;
} catch (InterruptedException e) {
Log.e(LOGTAG, "stopBackgroundThread", e);
}
}
protected boolean initializeCamera() {
Log.i(LOGTAG, "initializeCamera");
CameraManager manager = (CameraManager) getContext().getSystemService(Context.CAMERA_SERVICE);
try {
String camList[] = manager.getCameraIdList();
if (camList.length == 0) {
Log.e(LOGTAG, "Error: camera isn't detected.");
return false;
}
if (mCameraIndex == CameraBridgeViewBase.CAMERA_ID_ANY) {
mCameraID = camList[0];
} else {
for (String cameraID : camList) {
CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraID);
if ((mCameraIndex == CameraBridgeViewBase.CAMERA_ID_BACK &&
characteristics.get(CameraCharacteristics.LENS_FACING) == CameraCharacteristics.LENS_FACING_BACK) ||
(mCameraIndex == CameraBridgeViewBase.CAMERA_ID_FRONT &&
characteristics.get(CameraCharacteristics.LENS_FACING) == CameraCharacteristics.LENS_FACING_FRONT)
) {
mCameraID = cameraID;
break;
}
}
}
if (mCameraID != null) {
//CameraCharacteristics characteristics = manager.getCameraCharacteristics(mCameraID);
//characteristics = manager.
Log.i(LOGTAG, "Opening camera: " + mCameraID);
manager.openCamera(mCameraID, mStateCallback, mBackgroundHandler);
}
return true;
} catch (CameraAccessException e) {
Log.e(LOGTAG, "OpenCamera - Camera Access Exception", e);
} catch (IllegalArgumentException e) {
Log.e(LOGTAG, "OpenCamera - Illegal Argument Exception", e);
} catch (SecurityException e) {
Log.e(LOGTAG, "OpenCamera - Security Exception", e);
}
return false;
}
private final CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(CameraDevice cameraDevice) {
mCameraDevice = cameraDevice;
createCameraPreviewSession();
}
@Override
public void onDisconnected(CameraDevice cameraDevice) {
cameraDevice.close();
mCameraDevice = null;
}
@Override
public void onError(CameraDevice cameraDevice, int error) {
cameraDevice.close();
mCameraDevice = null;
}
};
private void createCameraPreviewSession() {
final int w = widthP;//mPreviewSize.getWidth(), h = mPreviewSize.getHeight();
final int h = heightP;
Log.i(LOGTAG, "createCameraPreviewSession(" + w + "x" + h + ")");
if (w < 0 || h < 0)
return;
try {
if (null == mCameraDevice) {
Log.e(LOGTAG, "createCameraPreviewSession: camera isn't opened");
return;
}
if (null != mCaptureSession) {
Log.e(LOGTAG, "createCameraPreviewSession: mCaptureSession is already started");
return;
}
mImageReader = ImageReader.newInstance(w, h, mPreviewFormat, 2);
mImageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() {
@Override
public void onImageAvailable(ImageReader reader) {
Image image = reader.acquireLatestImage();
if (image == null)
return;
// sanity checks - 3 planes
Image.Plane[] planes = image.getPlanes();
assert (planes.length == 3);
assert (image.getFormat() == mPreviewFormat);
// see also https://developer.android.com/reference/android/graphics/ImageFormat.html#YUV_420_888
// Y plane (0) non-interleaved => stride == 1; U/V plane interleaved => stride == 2
assert (planes[0].getPixelStride() == 1);
assert (planes[1].getPixelStride() == 2);
assert (planes[2].getPixelStride() == 2);
ByteBuffer y_plane = planes[0].getBuffer();
ByteBuffer uv_plane = planes[1].getBuffer();
Mat y_mat = new Mat(h, w, CvType.CV_8UC1, y_plane);
Mat uv_mat = new Mat(h / 2, w / 2, CvType.CV_8UC2, uv_plane);
JavaCamera2Frame tempFrame = new JavaCamera2Frame(y_mat, uv_mat, w, h);
deliverAndDrawFrame(tempFrame);
tempFrame.release();
image.close();
}
}, mBackgroundHandler);
Surface surface = mImageReader.getSurface();
mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
mPreviewRequestBuilder.addTarget(surface);
mCameraDevice.createCaptureSession(Arrays.asList(surface),
new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(CameraCaptureSession cameraCaptureSession) {
Log.i(LOGTAG, "createCaptureSession::onConfigured");
if (null == mCameraDevice) {
return; // camera is already closed
}
mCaptureSession = cameraCaptureSession;
try {
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE,
CaptureRequest.CONTROL_AF_MODE_OFF);
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE,
CaptureRequest.CONTROL_AE_MODE_OFF);
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_TARGET_FPS_RANGE, new Range<Integer>(30,30));
mCaptureSession.setRepeatingRequest(mPreviewRequestBuilder.build(), null, mBackgroundHandler);
Log.i(LOGTAG, "CameraPreviewSession has been started");
} catch (Exception e) {
Log.e(LOGTAG, "createCaptureSession failed", e);
}
}
@Override
public void onConfigureFailed(CameraCaptureSession cameraCaptureSession) {
Log.e(LOGTAG, "createCameraPreviewSession failed");
}
},
null
);
} catch (CameraAccessException e) {
Log.e(LOGTAG, "createCameraPreviewSession", e);
}
}
@Override
protected void disconnectCamera() {
Log.i(LOGTAG, "closeCamera");
try {
CameraDevice c = mCameraDevice;
mCameraDevice = null;
if (null != mCaptureSession) {
mCaptureSession.close();
mCaptureSession = null;
}
if (null != c) {
c.close();
}
if (null != mImageReader) {
mImageReader.close();
mImageReader = null;
}
} finally {
stopBackgroundThread();
}
}
boolean calcPreviewSize(final int width, final int height) {
Log.i(LOGTAG, "calcPreviewSize: " + width + "x" + height);
if (mCameraID == null) {
Log.e(LOGTAG, "Camera isn't initialized!");
return false;
}
CameraManager manager = (CameraManager) getContext().getSystemService(Context.CAMERA_SERVICE);
try {
CameraCharacteristics characteristics = manager.getCameraCharacteristics(mCameraID);
StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
int bestWidth = 0, bestHeight = 0;
float aspect = (float) width / height;
android.util.Size[] sizes = map.getOutputSizes(ImageReader.class);
bestWidth = sizes[0].getWidth();
bestHeight = sizes[0].getHeight();
for (android.util.Size sz : sizes) {
int w = sz.getWidth(), h = sz.getHeight();
Log.d(LOGTAG, "trying size: " + w + "x" + h);
if (width >= w && height >= h && bestWidth <= w && bestHeight <= h
&& Math.abs(aspect - (float) w / h) < 0.2) {
bestWidth = w;
bestHeight = h;
}
}
Log.i(LOGTAG, "best size: " + bestWidth + "x" + bestHeight);
assert(!(bestWidth == 0 || bestHeight == 0));
if (mPreviewSize.getWidth() == bestWidth && mPreviewSize.getHeight() == bestHeight)
return false;
else {
mPreviewSize = new android.util.Size(widthP, heightP);
return true;
}
} catch (CameraAccessException e) {
Log.e(LOGTAG, "calcPreviewSize - Camera Access Exception", e);
} catch (IllegalArgumentException e) {
Log.e(LOGTAG, "calcPreviewSize - Illegal Argument Exception", e);
} catch (SecurityException e) {
Log.e(LOGTAG, "calcPreviewSize - Security Exception", e);
}
return false;
}
@Override
protected boolean connectCamera(int width, int height) {
Log.i(LOGTAG, "setCameraPreviewSize(" + width + "x" + height + ")");
startBackgroundThread();
initializeCamera();
try {
boolean needReconfig = calcPreviewSize(width, height);
mFrameWidth = mPreviewSize.getWidth();
mFrameHeight = mPreviewSize.getHeight();
if ((getLayoutParams().width == LayoutParams.MATCH_PARENT) && (getLayoutParams().height == LayoutParams.MATCH_PARENT))
mScale = Math.min(((float)height)/mFrameHeight, ((float)width)/mFrameWidth);
else
mScale = 0;
AllocateCache();
if (needReconfig) {
if (null != mCaptureSession) {
Log.d(LOGTAG, "closing existing previewSession");
mCaptureSession.close();
mCaptureSession = null;
}
createCameraPreviewSession();
}
} catch (RuntimeException e) {
throw new RuntimeException("Interrupted while setCameraPreviewSize.", e);
}
return true;
}
private class JavaCamera2Frame implements CvCameraViewFrame {
@Override
public Mat gray() {
return mYuvFrameData.submat(0, mHeight, 0, mWidth);
}
@Override
public Mat rgba() {
if (mPreviewFormat == ImageFormat.NV21)
Imgproc.cvtColor(mYuvFrameData, mRgba, Imgproc.COLOR_YUV2RGBA_NV21, 4);
else if (mPreviewFormat == ImageFormat.YV12)
Imgproc.cvtColor(mYuvFrameData, mRgba, Imgproc.COLOR_YUV2RGB_I420, 4); // COLOR_YUV2RGBA_YV12 produces inverted colors
else if (mPreviewFormat == ImageFormat.YUV_420_888) {
assert (mUVFrameData != null);
Imgproc.cvtColorTwoPlane(mYuvFrameData, mUVFrameData, mRgba, Imgproc.COLOR_YUV420sp2BGRA);
// TODO: Here we had to change vom Imgproc.COLOR_YUV2RGBA_NV21 to Imgproc.COLOR_YUV420sp2BGRA to get the correct colors.
} else
throw new IllegalArgumentException("Preview Format can be NV21 or YV12");
return mRgba;
}
public JavaCamera2Frame(Mat Yuv420sp, int width, int height) {
super();
mWidth = width;
mHeight = height;
mYuvFrameData = Yuv420sp;
mUVFrameData = null;
mRgba = new Mat();
}
public JavaCamera2Frame(Mat Y, Mat UV, int width, int height) {
super();
mWidth = width;
mHeight = height;
mYuvFrameData = Y;
mUVFrameData = UV;
mRgba = new Mat();
}
public void release() {
mRgba.release();
}
private Mat mYuvFrameData;
private Mat mUVFrameData;
private Mat mRgba;
private int mWidth;
private int mHeight;
};
}
答案 0 :(得分：1)
从表面上看，修改后的calcPreviewSize()方法可能存在问题：即使预览尺寸不应更改，它也可能会返回 true 。
你会看到
I/JavaCamera2View best size: WWWWxHHH
，其中WWWW不是640而HHH不是480。
更改预览尺寸涉及关闭并重新打开 previewSession ，并需要时间。您使用的代码需要重复调用calcPreviewSize()才能返回 false 。
可能的解决方法是以这种方式重写方法：
boolean calcPreviewSize(final int width, final int height) {
Log.i(LOGTAG, "calcPreviewSize: " + width + "x" + height);
if (mCameraID == null) {
Log.e(LOGTAG, "Camera isn't initialized!");
return false;
}
if (mPreviewSize.getWidth() == widthP && mPreviewSize.getHeight() == heightP) {
return false;
}
else {
mPreviewSize = new android.util.Size(widthP, heightP);
return true;
}
}