Android OpenCV VideoCapture:：retrieve（&；mat）导致致命信号11

因此，我正在尝试制作一个android应用程序，它将通过OpenCV通过JNI和NDK逐帧打开一个视频文件，检测每个帧中的人脸并显示它们（最终目标是加速算法，更好地适应糟糕的移动处理）

我尝试的第一个方法没有结果，它只返回null

第二种方法是，它确实可以像预期的那样工作，但速度非常慢（高达2fps；太慢），部分原因是您必须从FFMpegMMR的位图转换为Mat，然后进行检测和绘制，然后再转换回位图，这是我的穴居人非常愿意尝试的

我目前正在使用的第三种方法是VideoCapture grab（）和retrieve（）。我为本机代码制作了一个包装器，主要是通过从OpenCV示例复制facedtector。我还尝试了read（），据说它将两者结合在一起，但它也会导致致命信号11（在某些被上帝抛弃的OpenCV或Android平台级别上出现分段错误）

下面是应用程序获取绝对文件路径的方式（请注意，它确实适用于FFMpegMMR）：

这是调用本机方法的java包装器和使用结果的地方：

class AsyncPlay extends AsyncTask<String, Mat, Bitmap>
        {

        @Override
        protected Bitmap doInBackground(String... params) {
            //for(;play;)
            {
                if(play)
                {
                    if(currentTime==0)
                    {
                        test=new Test();
                        test.startTime.setToNow();
                        test.type="Video";
                        frameGrabber.open(videoFilePath);
                    }
            //publishProgress(retriever.getFrameAtTime(currentTime*1000+111,
                    //      FFmpegMediaMetadataRetriever.OPTION_CLOSEST));


                    Mat tmp=new Mat();
                    //frameGrabber.read(tmp);
                    frameGrabber.grab();
                    frameGrabber.retrieve(tmp);
                    publishProgress(tmp);

                    currentTime+=111;
                    if(currentTime*1000>=duration*1000)
                    {
                        currentTime=0;
                        test.endTime.setToNow();
                        tester.publishResult(test);
                        frameGrabber.release();
                    }
                }
                try 
                {
                    Thread.sleep(111);
                } catch (InterruptedException e) 
                {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            return null;
        }
        @Override
        protected void onProgressUpdate(Mat... values) {

            //face detection logic goes here
            //Bitmap bmp=values[0];

            //Mat rgbMat = new Mat();
            //Utils.bitmapToMat(bmp, rgbMat);

            DetectionResult detectionResult = openCVFaceDetector.detectFromImage(values[0], Imgproc.COLOR_RGB2GRAY);//Detecting with a native detector from OpenCV

            test.addDetection(detectionResult.detection);

            imageViewOriginal.setImageBitmap(detectionResult.detectedImage);

            super.onProgressUpdate(values);
        }

    };`

这是它的本机部分（导致错误的确切行是

result=（（VideoCapture*）thiz）->retrieve（*（（Mat*）imageMat））；

，它位于方法nativeRetrieve（）中

<调试这个代码的问题是，它是Eclipse中的JNI，我不知道如何在Eclipse中进行调试C++，这就是为什么我使用日志消息来查找代码中的缺陷。不起作用，我发现并消除了一个bug，我忘记了将其传递给方法。retrieve（）的问题是我一生都找不到它的源代码。highgui.hpp中有部分定义，但没有实现，我可以将日志消息放在其中帮助我调试

可能的解决办法是：

• retrieve（）支持的不同文件格式，只是我不知道可能是哪种文件格式
• 使用非绝对文件路径？尽管open（）和grab（）都不会导致致命信号
• 放弃整个东西，使用PNG（不过我真的很想弄清楚）

因此，如果有人能告诉我在哪里可以找到retrieve（）和read（）的实现，我将不胜感激。或者如果我错过了一些明显而愚蠢的东西（我希望如此）

---

同时，我会尝试在Eclipse中调试C++并尝试另一种格式。

< P>找到它，最后，按照Aleksander的建议，我设法找到了从java传递到JNI的对象的类型不匹配。 事实证明，错误出现在java部分，在java部分中声明了本机方法。我没有传递Mat，而是传递了Mat.getNativeObjAddr（），这是一个很长的过程

所以不是

    private static native boolean nativeRetrieve(long thiz, Mat imageMat);
    private static native boolean nativeRead(long thiz, Mat imageMat);
    public boolean retrieve(Mat imageMat)
    {
        return nativeRetrieve(mNativeObj, imageMat);
    }    
    public boolean read(Mat imageMat)
    {
        return nativeRead(mNativeObj, imageMat);
    }    

我用了这个：

        private static native boolean nativeRetrieve(long thiz, long imageMat);
        private static native boolean nativeRead(long thiz, long imageMat);
        public boolean retrieve(Mat imageMat)
        {
            return nativeRetrieve(mNativeObj, imageMat.getNativeObjAddr());
        }    
        public boolean read(Mat imageMat)
        {
            return nativeRead(mNativeObj, imageMat.getNativeObjAddr());
        }   

---

注意：通过C++，C++中的错误类型不会触发异常，即使代码在Test.catch中。TIG.catch可能是错误的，我不知道。< / P> OK，我以前使用Python包装器，并且面对同样的事情。基本上你需要查看C++文档并尝试理解C++上的问题。IDE。请将代码缩短为仅与错误相关的那些东西，即抛出它的方法、它的设置和失败方法调用的方法？在C++方面，我将其缩小到<代码>结果=（（VixCopthOx*）THZ）->检索（（*（（Mat*）IMAGEMAT）））。这就是我所能得到的，因为我没有找到highgui的源代码。好吧，对不起，我对JNI不太在行，所以这可能是个愚蠢的问题，但是为什么你在调用

（*（（Mat*）imageMat）时，会这样使用
（VideoCapture*）thiz
具有它必须拥有的类型，即C++中的代码> Matt和MIN，int通道＝0 < /COD>。我在Python绑定中遇到的问题之一是，有时您对Python（java）有一个引用。侧到一些C++对象，没有C++类型的期望，这是错误的。TIZ是我正在使用的视频捕获对象。因为这是JNI，在CPP里面没有真正的类，在构造类之后，当你有引用时，你必须把这个引用从java端传递到原生CPP方法。ce in.cpp中，您还必须将其强制转换为所需的类才能获得其方法。我复制了大部分代码示例DetectionBasedTracker，它可以正常工作。您基本上是以长格式传递引用，然后取消引用并强制转换它。您确实提出了一个很好的观点，我将对此进行研究，看看我是否以某种方式弄乱了文件类型。就是这样！我通过的是垫子而不是长垫子（指垫子）。非常感谢你的建议，你本可以挽救我的理智。我需要帮助，可以吗？
#include <string>
#include <vector>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <FrameGrabber_jni.h>

#include <android/log.h>

#define LOG_TAG "FrameGrabber"
#define LOGD(...) ((void)__android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__))

using namespace std;
using namespace cv;

inline void jStringToString(JNIEnv * jenv, jstring jString, string stdName)
{
    LOGD("Java_boris_springar_diplomska_FrameGrabber_jStringToString enter");
    LOGD("grabber is Making jnamestr");//this is buggy as hell, the line serves as a debug tool
    const char* jnamestr = jenv->GetStringUTFChars(jString, NULL);
    string stdNameTmp(jnamestr);
    stdName=stdNameTmp;
    LOGD("grabber is releasing jnamestr");
    jenv->ReleaseStringUTFChars(jString, jnamestr);
}

/*
 * CONSTRUCTOR AND DESTRUCTOR
 */
JNIEXPORT jlong JNICALL Java_boris_springar_diplomska_FrameGrabber_nativeCreateObject
(JNIEnv * jenv, jclass, jstring jFileName)
{
    LOGD("Java_boris_springar_diplomska_FrameGrabber_nativeCreateObject enter");
    string stdFileName;
    jStringToString(jenv, jFileName,stdFileName);
    jlong result = 0;

    try
    {
        result = (jlong)new VideoCapture(stdFileName);
    }
    catch(cv::Exception& e)
    {
        LOGD("nativeCreateObject caught cv::Exception: %s", e.what());
        jclass je = jenv->FindClass("org/opencv/core/CvException");
        if(!je)
            je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, e.what());
    }
    catch (...)
    {
        LOGD("nativeCreateObject caught unknown exception");
        jclass je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, "Unknown exception in JNI code of FrameGrabber.nativeCreateObject()");
        return 0;
    }

    LOGD("Java_boris_springar_diplomska_FrameGrabber_nativeCreateObject exit");
    return result;
}

//should work
JNIEXPORT void JNICALL Java_boris_springar_diplomska_FrameGrabber_nativeDestroyObject
(JNIEnv * jenv, jclass, jlong thiz)
{
    LOGD("Java_boris_springar_diplomska_FrameGrabber_nativeDestroyObject enter");
    try
    {
        if(thiz != 0)
        {
            delete (VideoCapture*)thiz;
        }
    }
    catch(cv::Exception& e)
    {
        LOGD("nativeestroyObject caught cv::Exception: %s", e.what());
        jclass je = jenv->FindClass("org/opencv/core/CvException");
        if(!je)
            je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, e.what());
    }
    catch (...)
    {
        LOGD("nativeDestroyObject caught unknown exception");
        jclass je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, "Unknown exception in JNI code of FrameGrabber.nativeDestroyObject()");
    }
    LOGD("Java_boris_springar_diplomska_FrameGrabber_nativeDestroyObject exit");
}


/*
 * CORE METHODS
 */

//Open function opens the filename for playing
JNIEXPORT jboolean JNICALL Java_boris_springar_diplomska_FrameGrabber_nativeOpen
(JNIEnv * jenv, jclass,jlong thiz,jstring jFileName)
{
    LOGD("Java_boris_springar_diplomska_FrameGrabber_open enter");
    string stdFileName;
    jStringToString(jenv, jFileName,stdFileName);

    jboolean result = false;

    try
    {
        result = ((VideoCapture*)thiz)->open(stdFileName);
    }
    catch(cv::Exception& e)
    {
        LOGD("frame grabber open exception caught cv::Exception: %s", e.what());
        jclass je = jenv->FindClass("org/opencv/core/CvException");
        if(!je)
            je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, e.what());
    }
    catch (...)
    {
        LOGD("frame grabber open caught unknown exception");
        jclass je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, "Unknown exception in JNI code of FrameGrabber.open()");
        return 0;
    }

    LOGD("Java_boris_springar_diplomska_FrameGrabber_open exit");

    return result;
}

//grab grabs the next frame from file or camera
JNIEXPORT jboolean JNICALL Java_boris_springar_diplomska_FrameGrabber_nativeGrab
(JNIEnv * jenv, jclass,jlong thiz)
{
    LOGD("Java_boris_springar_diplomska_FrameGrabber_grab enter");
    jboolean result = false;

    try
    {
        result = ((VideoCapture*)thiz)->grab();
    }
    catch(cv::Exception& e)
    {
        LOGD("frame grabber grab exception caught cv::Exception: %s", e.what());
        jclass je = jenv->FindClass("org/opencv/core/CvException");
        if(!je)
            je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, e.what());
    }
    catch (...)
    {
        LOGD("frame grabber grab caught unknown exception");
        jclass je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, "Unknown exception in JNI code of FrameGrabber.grab()");
        return 0;
    }

    LOGD("Java_boris_springar_diplomska_FrameGrabber_grab exit");

    return result;
}

//retrieve retrieves the next frame and writes it to the image matrix
JNIEXPORT jboolean JNICALL Java_boris_springar_diplomska_FrameGrabber_nativeRetrieve
(JNIEnv * jenv, jclass,jlong thiz, jlong imageMat)
{
    LOGD("Java_boris_springar_diplomska_FrameGrabber_retrieve enter");
    jboolean result = false;

    try
    {
        LOGD("grabber trying to retrieve");
        result = ((VideoCapture*)thiz)->retrieve((*((Mat*)imageMat)));//should write the current frame to the image matrix
    }
    catch(cv::Exception& e)
    {
        LOGD("frame grabber retrieve exception caught cv::Exception: %s", e.what());
        jclass je = jenv->FindClass("org/opencv/core/CvException");
        if(!je)
            je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, e.what());
    }
    catch (...)
    {
        LOGD("frame grabber retrieve caught unknown exception");
        jclass je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, "Unknown exception in JNI code of FrameGrabber.retrieve(fileName)");
        return 0;
    }

    LOGD("Java_boris_springar_diplomska_FrameGrabber_retrieve exit");

    return result;
}

//read combines grab and retrieve and writes the stuff to the image matrix
JNIEXPORT jboolean JNICALL Java_boris_springar_diplomska_FrameGrabber_nativeRead
(JNIEnv * jenv, jclass,jlong thiz, jlong imageMat)
{
    LOGD("Java_boris_springar_diplomska_FrameGrabber_read enter");
    LOGD("grabber setting result to false");
    jboolean result = false;

    try
    {
        LOGD("grabber trying to read capture");
        result = ((VideoCapture*)thiz)->read((*((Mat*)imageMat)));//should write the current frame to the image matrix
    }
    catch(cv::Exception& e)
    {
        LOGD("frame grabber read exception caught cv::Exception: %s", e.what());
        jclass je = jenv->FindClass("org/opencv/core/CvException");
        if(!je)
            je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, e.what());
    }
    catch (...)
    {
        LOGD("frame grabber read caught unknown exception");
        jclass je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, "Unknown exception in JNI code of FrameGrabber.open(fileName)");
        return 0;
    }

    LOGD("Java_boris_springar_diplomska_FrameGrabber_read exit");

    return result;
}

//Release releases the resource it's using, I hope
JNIEXPORT void JNICALL Java_boris_springar_diplomska_FrameGrabber_nativeRelease
(JNIEnv * jenv, jclass,jlong thiz)
{
    LOGD("Java_boris_springar_diplomska_FrameGrabber_release enter");
    jboolean result = false;

    try
    {
        ((VideoCapture*)thiz)->release();//should release
    }
    catch(cv::Exception& e)
    {
        LOGD("frame grabber read exception caught cv::Exception: %s", e.what());
        jclass je = jenv->FindClass("org/opencv/core/CvException");
        if(!je)
            je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, e.what());
    }
    catch (...)
    {
        LOGD("frame grabber release caught unknown exception");
        jclass je = jenv->FindClass("java/lang/Exception");
        jenv->ThrowNew(je, "Unknown exception in JNI code of FrameGrabber.open(fileName)");
    }

    LOGD("Java_boris_springar_diplomska_FrameGrabber_release exit");
}

07-22 17:36:24.886: D/FrameGrabber(15359): Java_boris_springar_diplomska_FrameGrabber_nativeCreateObject enter
07-22 17:36:24.886: D/FrameGrabber(15359): Java_boris_springar_diplomska_FrameGrabber_jStringToString enter
07-22 17:36:24.886: D/FrameGrabber(15359): grabber is Making jnamestr
07-22 17:36:24.886: D/FrameGrabber(15359): grabber is releasing jnamestr
07-22 17:36:24.886: D/FrameGrabber(15359): Java_boris_springar_diplomska_FrameGrabber_nativeCreateObject exit
07-22 17:36:24.936: I/dalvikvm(15359): threadid=3: reacting to signal 3
07-22 17:36:24.936: I/dalvikvm(15359): Wrote stack traces to '/data/anr/traces.txt'
07-22 17:36:24.946: D/libEGL(15359): loaded /system/lib/egl/libEGL_mali.so
07-22 17:36:24.956: D/libEGL(15359): loaded /system/lib/egl/libGLESv1_CM_mali.so
07-22 17:36:24.976: D/libEGL(15359): loaded /system/lib/egl/libGLESv2_mali.so
07-22 17:36:25.006: D/OpenGLRenderer(15359): Enabling debug mode 0
07-22 17:36:27.336: D/FrameGrabber(15359): Java_boris_springar_diplomska_FrameGrabber_open enter
07-22 17:36:27.336: D/FrameGrabber(15359): Java_boris_springar_diplomska_FrameGrabber_jStringToString enter
07-22 17:36:27.336: D/FrameGrabber(15359): grabber is Making jnamestr
07-22 17:36:27.336: D/FrameGrabber(15359): grabber is releasing jnamestr
07-22 17:36:27.336: D/FrameGrabber(15359): Java_boris_springar_diplomska_FrameGrabber_open exit
07-22 17:36:27.336: D/FrameGrabber(15359): Java_boris_springar_diplomska_FrameGrabber_grab enter
07-22 17:36:27.336: D/FrameGrabber(15359): Java_boris_springar_diplomska_FrameGrabber_grab exit
07-22 17:36:27.336: D/FrameGrabber(15359): Java_boris_springar_diplomska_FrameGrabber_retrieve enter
07-22 17:36:27.336: D/FrameGrabber(15359): grabber trying to retrieve
07-22 17:36:27.336: A/libc(15359): Fatal signal 11 (SIGSEGV) at 0x1d400019 (code=1)

    private static native boolean nativeRetrieve(long thiz, Mat imageMat);
    private static native boolean nativeRead(long thiz, Mat imageMat);
    public boolean retrieve(Mat imageMat)
    {
        return nativeRetrieve(mNativeObj, imageMat);
    }    
    public boolean read(Mat imageMat)
    {
        return nativeRead(mNativeObj, imageMat);
    }    

        private static native boolean nativeRetrieve(long thiz, long imageMat);
        private static native boolean nativeRead(long thiz, long imageMat);
        public boolean retrieve(Mat imageMat)
        {
            return nativeRetrieve(mNativeObj, imageMat.getNativeObjAddr());
        }    
        public boolean read(Mat imageMat)
        {
            return nativeRead(mNativeObj, imageMat.getNativeObjAddr());
        }