分配OpenCV Mat对象会导致内存泄漏

Question

I want to assign frame ( Mat object) from function parameter into object variable, as shown in the code below. This function should be called may times (for each frame from the video camera), but this line

this->nFrame = frame;

causes a memory leak (when commented there is no error!).

NOTE The function setCurrentFrame is called inside JNI function, where this JNI function is called every time I want to process the frame from the video camera.

The JNI function is like:

JNIEXPORT jbyteArray JNICALL Java_com_adhamenaya_Native_run(JNIEnv * env,
        jobject obj, jstring faceCascadeFile, jstring noseCascadeFile,
        jstring landmarks, jlong frame) {

    MyClass gsys;
    cv::Mat& inFrame = *(cv::Mat*) frame;
    gsys.setCurrentFrame(inFrame);


    // SOME PROCESSING FOR THE FRAME 


    inFrame.release();
    gsys.release();

    ......
    ......
}

The code for C++ function (setCurrentFrame)

void MyClass::setCurrentFrame(cv::Mat& frame) {
    cv::Size2d imgRes;
    float resRatio;

    if (frame.cols > frame.rows) {
        //landscape
        imgRes.width = 640.0f;
        resRatio = frame.cols / 640.0f;
        imgRes.height = floor(frame.rows / resRatio);
    } else {
        //portrait
        imgRes.height = 640.0f;
        resRatio = frame.rows / 640.0f;
        imgRes.width = floor(frame.cols / resRatio);
    }

    //save scaled height, width for further use
    this->frameWidth = nFrame.cols;
    this->frameHeight = nFrame.rows;

    //set frame and increment frameCount
    this->nFrame = frame;
    this->frameCount++;
}

Kindly, can you help me to solve this problem ? I tried to release the frame by calling :

void MyClass::release(void) {
    this->nFrame = cv::Mat();
}

nothing happened, even like this:

void MyClass::release(void) {
    this->nFrame.release();
}

Still the same error!

Edit

MyClass.h

class MyClass {

public:
    cv::Mat nFrame;

    MyClass ();
    ~MyClass ();
    void release (void);
    void setCurrentFrame(cv::Mat& frame);

};

Answer 1

In the jni file, the order of releasing frame objects can be erroneus:

inFrame.release();
gsys.release();

should be

gsys.release();
inFrame.release();

because when you free source frame then frame reference in gsys is invalidated.