我正在尝试在Galaxy S4上使用Camera2 API捕获图像数据。ImageReader用作表面提供者。已尝试使用ImageFormat.YV12和ImageFormat.YUV_420_888两种图像格式，结果相同。
设置似乎没有问题，并且我使用ImageReader从Image获取了图像。该图像有3个平面。缓冲区的大小符合预期，即Y平面为Width*Height，另外两个平面为（Width*Height）/4。
问题在于我无法正确地获取数据。第一个问题是Y平面数据是镜像的。虽然可以处理，但这很奇怪，因此我想知道是否应该这样做。
更糟糕的问题是其他两个平面似乎根本没有正确传递数据。例如，对于640x480的图像大小，导致U和V缓冲区大小为76800字节，只有缓冲区的前320个字节是非零值。这个数字会变化，并且似乎不遵循不同图像大小之间的固定比率，但对于每个大小的图像，它似乎是一致的。
我想知道是否有什么我在使用此API时忽略的东西。以下是代码。
设置似乎没有问题，并且我使用ImageReader从Image获取了图像。该图像有3个平面。缓冲区的大小符合预期，即Y平面为Width*Height，另外两个平面为（Width*Height）/4。
问题在于我无法正确地获取数据。第一个问题是Y平面数据是镜像的。虽然可以处理，但这很奇怪，因此我想知道是否应该这样做。
更糟糕的问题是其他两个平面似乎根本没有正确传递数据。例如，对于640x480的图像大小，导致U和V缓冲区大小为76800字节，只有缓冲区的前320个字节是非零值。这个数字会变化，并且似乎不遵循不同图像大小之间的固定比率，但对于每个大小的图像，它似乎是一致的。
我想知道是否有什么我在使用此API时忽略的东西。以下是代码。
public class OnboardCamera {
private final String TAG = "OnboardCamera";
int mWidth = 1280;
int mHeight = 720;
int mYSize = mWidth*mHeight;
int mUVSize = mYSize/4;
int mFrameSize = mYSize+(mUVSize*2);
//handler for the camera
private HandlerThread mCameraHandlerThread;
private Handler mCameraHandler;
//the size of the ImageReader determines the output from the camera.
private ImageReader mImageReader = ImageReader.newInstance(mWidth, mHeight, ImageFormat.YV12, 30);
private Surface mCameraRecieverSurface = mImageReader.getSurface();
{
mImageReader.setOnImageAvailableListener(mImageAvailListener, mCameraHandler);
}
private byte[] tempYbuffer = new byte[mYSize];
private byte[] tempUbuffer = new byte[mUVSize];
private byte[] tempVbuffer = new byte[mUVSize];
ImageReader.OnImageAvailableListener mImageAvailListener = new ImageReader.OnImageAvailableListener() {
@Override
public void onImageAvailable(ImageReader reader) {
//when a buffer is available from the camera
//get the image
Image image = reader.acquireNextImage();
Image.Plane[] planes = image.getPlanes();
//copy it into a byte[]
byte[] outFrame = new byte[mFrameSize];
int outFrameNextIndex = 0;
ByteBuffer sourceBuffer = planes[0].getBuffer();
sourceBuffer.get(tempYbuffer, 0, tempYbuffer.length);
ByteBuffer vByteBuf = planes[1].getBuffer();
vByteBuf.get(tempVbuffer);
ByteBuffer yByteBuf = planes[2].getBuffer();
yByteBuf.get(tempUbuffer);
//free the Image
image.close();
}
};
OnboardCamera() {
mCameraHandlerThread = new HandlerThread("mCameraHandlerThread");
mCameraHandlerThread.start();
mCameraHandler = new Handler(mCameraHandlerThread.getLooper());
}
@Override
public boolean startProducing() {
CameraManager cm = (CameraManager) Ten8Application.getAppContext().getSystemService(Context.CAMERA_SERVICE);
try {
String[] cameraList = cm.getCameraIdList();
for (String cd: cameraList) {
//get camera characteristics
CameraCharacteristics mCameraCharacteristics = cm.getCameraCharacteristics(cd);
//check if the camera is in the back - if not, continue to next
if (mCameraCharacteristics.get(CameraCharacteristics.LENS_FACING) != CameraCharacteristics.LENS_FACING_BACK) {
continue;
}
//get StreamConfigurationMap - supported image formats
StreamConfigurationMap scm = mCameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
android.util.Size[] sizes = scm.getOutputSizes(ImageFormat.YV12);
cm.openCamera(cd, mDeviceStateCallback, mCameraHandler);
}
} catch (CameraAccessException e) {
e.printStackTrace();
Log.e(TAG, "CameraAccessException detected", e);
}
return false;
}
private final CameraDevice.StateCallback mDeviceStateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(CameraDevice camera) {
//make list of surfaces to give to camera
List<Surface> surfaceList = new ArrayList<>();
surfaceList.add(mCameraRecieverSurface);
try {
camera.createCaptureSession(surfaceList, mCaptureSessionStateCallback, mCameraHandler);
} catch (CameraAccessException e) {
Log.e(TAG, "createCaptureSession threw CameraAccessException.", e);
}
}
@Override
public void onDisconnected(CameraDevice camera) {
}
@Override
public void onError(CameraDevice camera, int error) {
}
};
private final CameraCaptureSession.StateCallback mCaptureSessionStateCallback = new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(CameraCaptureSession session) {
try {
CaptureRequest.Builder requestBuilder = session.getDevice().createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
requestBuilder.addTarget(mCameraRecieverSurface);
//set to null - image data will be produced but will not receive metadata
session.setRepeatingRequest(requestBuilder.build(), null, mCameraHandler);
} catch (CameraAccessException e) {
Log.e(TAG, "createCaptureSession threw CameraAccessException.", e);
}
}
@Override
public void onConfigureFailed(CameraCaptureSession session) {
}
};
}