使用JavaCV库旋转图像的问题

Question

I am writing an Android application which records video for a specified amount of time. Everything works fine if I record using the smartphone's back camera. The app has a feature to pause/record feature like in Vine app. The issue comes when recording using the device's front camera. The video surface frame looks fine when storing/playing the video the video is upside down. There is a lot of things discussed about this issue everywhere. But I didn't find any solution that WORKS.

Have a look at the code and image mentioned below.

Here is the original image taken from front camera. I have turned it upside down for a better view.

Here is what I actually get after rotation:

Method:

     IplImage copy = cvCloneImage(image);
     IplImage rotatedImage = cvCreateImage(cvGetSize(copy), copy.depth(), copy.nChannels());
     //Define Rotational Matrix
     CvMat mapMatrix = cvCreateMat(2, 3, CV_32FC1);

     //Define Mid Point
     CvPoint2D32f centerPoint = new CvPoint2D32f();
     centerPoint.x(copy.width() / 2);
     centerPoint.y(copy.height() / 2);

     //Get Rotational Matrix
     cv2DRotationMatrix(centerPoint, angle, 1.0, mapMatrix);

     //Rotate the Image
     cvWarpAffine(copy, rotatedImage, mapMatrix, CV_INTER_CUBIC + CV_WARP_FILL_OUTLIERS, cvScalarAll(170));
     cvReleaseImage(copy);
     cvReleaseMat(mapMatrix);

I have tried doing

     double angleTemp = angle;

     angleTemp= ((angleTemp / 90)%4)*90;       
     final int number = (int) Math.abs(angleTemp/90);

     for(int i = 0; i != number; ++i){            
         cvTranspose(rotatedImage, rotatedImage);
         cvFlip(rotatedImage, rotatedImage, 0);           
     }

Ends up in throwing exception saying that source and destination doesn't match with number of columns and rows.

Update:

Video is recorded in this way.

IplImage newImage = null;
if(cameraSelection == CameraInfo.CAMERA_FACING_FRONT){
    newImage = videoRecorder.rotate(yuvIplImage, 180);
    videoRecorder.record(newImage);
}
else
    videoRecorder.record(yuvIplImage);  

Rotation is done in this way:

    IplImage img = IplImage.create(image.height(), image.width(),
            image.depth(), image.nChannels());

    for (int i = 0; i < 180; i++) {
        cvTranspose(image, img);
        cvFlip(img, img, 0);
    }

Can anyone point out what is wrong here if you have experienced this before?

Answer 1

Seeing that you already have an IplImage, you may be able to find this helpful. I have modified the onPreviewFrame method of this Open Source Android Touch-To-Record library to take transpose and resize a captured frame.

I defined "yuvIplImage" as following in my setCameraParams() method.

IplImage yuvIplImage = IplImage.create(mPreviewSize.height, mPreviewSize.width, opencv_core.IPL_DEPTH_8U, 2);

Also initialize video recorder like this, sending width as height and vice versa:

//call initVideoRecorder() method like this to initialize videoRecorder object of FFmpegFrameRecorder class.
initVideoRecorder(strVideoPath, mPreview.getPreviewSize().height, mPreview.getPreviewSize().width, recorderParameters);

//method implementation
public void initVideoRecorder(String videoPath, int width, int height, RecorderParameters recorderParameters)
{
    Log.e(TAG, "initVideoRecorder");

    videoRecorder = new FFmpegFrameRecorder(videoPath, width, height, 1);
    videoRecorder.setFormat(recorderParameters.getVideoOutputFormat());
    videoRecorder.setSampleRate(recorderParameters.getAudioSamplingRate());
    videoRecorder.setFrameRate(recorderParameters.getVideoFrameRate());
    videoRecorder.setVideoCodec(recorderParameters.getVideoCodec());
    videoRecorder.setVideoQuality(recorderParameters.getVideoQuality());
    videoRecorder.setAudioQuality(recorderParameters.getVideoQuality());
    videoRecorder.setAudioCodec(recorderParameters.getAudioCodec());
    videoRecorder.setVideoBitrate(1000000);
    videoRecorder.setAudioBitrate(64000);
}

This is my onPreviewFrame() method:

@Override
public void onPreviewFrame(byte[] data, Camera camera)
{

    long frameTimeStamp = 0L;

    if(FragmentCamera.mAudioTimestamp == 0L && FragmentCamera.firstTime > 0L)
    {
        frameTimeStamp = 1000L * (System.currentTimeMillis() - FragmentCamera.firstTime);
    }
    else if(FragmentCamera.mLastAudioTimestamp == FragmentCamera.mAudioTimestamp)
    {
        frameTimeStamp = FragmentCamera.mAudioTimestamp + FragmentCamera.frameTime;
    }
    else
    {
        long l2 = (System.nanoTime() - FragmentCamera.mAudioTimeRecorded) / 1000L;
        frameTimeStamp = l2 + FragmentCamera.mAudioTimestamp;
        FragmentCamera.mLastAudioTimestamp = FragmentCamera.mAudioTimestamp;
    }

    synchronized(FragmentCamera.mVideoRecordLock)
    {
        if(FragmentCamera.recording && FragmentCamera.rec && lastSavedframe != null && lastSavedframe.getFrameBytesData() != null && yuvIplImage != null)
        {
            FragmentCamera.mVideoTimestamp += FragmentCamera.frameTime;

            if(lastSavedframe.getTimeStamp() > FragmentCamera.mVideoTimestamp)
            {
                FragmentCamera.mVideoTimestamp = lastSavedframe.getTimeStamp();
            }

            try
            {
                yuvIplImage.getByteBuffer().put(lastSavedframe.getFrameBytesData());

                IplImage bgrImage = IplImage.create(mPreviewSize.width, mPreviewSize.height, opencv_core.IPL_DEPTH_8U, 4);// In my case, mPreviewSize.width = 1280 and mPreviewSize.height = 720
                IplImage transposed = IplImage.create(mPreviewSize.height, mPreviewSize.width, yuvIplImage.depth(), 4);
                IplImage squared = IplImage.create(mPreviewSize.height, mPreviewSize.height, yuvIplImage.depth(), 4);

                int[] _temp = new int[mPreviewSize.width * mPreviewSize.height];

                Util.YUV_NV21_TO_BGR(_temp, data, mPreviewSize.width,  mPreviewSize.height);

                bgrImage.getIntBuffer().put(_temp);

                opencv_core.cvTranspose(bgrImage, transposed);
                opencv_core.cvFlip(transposed, transposed, 1);

                opencv_core.cvSetImageROI(transposed, opencv_core.cvRect(0, 0, mPreviewSize.height, mPreviewSize.height));
                opencv_core.cvCopy(transposed, squared, null);
                opencv_core.cvResetImageROI(transposed);

                videoRecorder.setTimestamp(lastSavedframe.getTimeStamp());
                videoRecorder.record(squared);
            }
            catch(com.googlecode.javacv.FrameRecorder.Exception e)
            {
                e.printStackTrace();
            }
        }

        lastSavedframe = new SavedFrames(data, frameTimeStamp);
    }
}

This code uses a method "YUV_NV21_TO_BGR", which I found from this link

Basically I had the same problem as yours, "The Green Devil problem on Android". Before adding "YUV_NV21_TO_BGR" method when I just took transpose of YuvIplImage, more importantly a combination of transpose, flip (with or without resizing), there was greenish output in resulting video, almost like yours. This "YUV_NV21_TO_BGR" method removed greenish output problem. Thanks to @David Han from above google groups thread.

Also you should know that all this processing (transpose, flip and resize), in onPreviewFrame, takes much time which causes a very serious hit on your Frames Per Second (FPS) rate. When I used this code, inside onPreviewFrame method, the resulting FPS of the recorded video was down to 3 frames/sec from 30fps.

Answer 2

When you do the transpose, the images width and height value gets replaced. Its like you rotate a rectangle by 90 degrees so that the height becomes width and vice-versa. So you need to do some thing like below:

    IplImage rotate(IplImage  IplSrc)
{
    IplImage img= IplImage.create(IplSrc.height(),
    IplSrc.width(),
    IplSrc.depth(),
    IplSrc.nChannels());
    cvTranspose(IplSrc, img);
    cvFlip(img, img, 0);
    //cvFlip(img, img, 0);
    return img;

}

Answer 3

    private void ChangeOrientation() throws  com.googlecode.javacv.FrameGrabber.Exception, com.googlecode.javacv.FrameRecorder.Exception {

        //Initialize Frame Grabber
        File f = new File(nativePath);
        frameGrabber = new FFmpegFrameGrabber(f);
        frameGrabber.start();

        Frame captured_frame = null;

        //Initialize Recorder
        initRecorder() ;

        //Loop through the grabber
        boolean inLoop=true;
        while (inLoop) 
        {
            captured_frame = frameGrabber.grabFrame();
            if (captured_frame == null) 
            {
                //break loop
                inLoop=false;
            }
            else if(inLoop)
            {
                // continue looping
                IplSrc=captured_frame.image;

                                  recorder.reocord(rotateImg(IplSrc));
            }
        }
        if (recorder != null ) 
        {
            recorder.stop();
            recorder.release();
            frameGrabber.stop();
            initRecorder=false;
        }
    }


private void initRecorder() throws com.googlecode.javacv.FrameRecorder.Exception 
    {
        recorder = new FFmpegFrameRecorder(editedPath, 
                frameGrabber.getImageWidth(), 
                frameGrabber.getImageHeight(),
                frameGrabber.getAudioChannels());

        recorder.setVideoCodec(avcodec.AV_CODEC_ID_H264);
        recorder.setFormat("mp4");
    recorder.setFrameRate(frameGrabber.getFrameRate());
            FrameRate=frameGrabber.getFrameRate();
        }
        recorder.setSampleFormat(frameGrabber.getSampleFormat());
        recorder.setSampleRate(frameGrabber.getSampleRate()); 
        recorder.start();
        initRecorder=true;
    }

Answer 4

This piece of code will help you handle problem when rotate IplImage

@Override
    public void onPreviewFrame(byte[] data, Camera camera) {  
         //IplImage newImage = cvCreateImage(cvGetSize(yuvIplimage), IPL_DEPTH_8U, 1);   
         if (recording) {    
             videoTimestamp = 1000 * (System.currentTimeMillis() - startTime);                
             yuvimage = IplImage.create(imageWidth, imageHeight * 3 / 2, IPL_DEPTH_8U,1); 
             yuvimage.getByteBuffer().put(data); 

             rgbimage = IplImage.create(imageWidth, imageHeight, IPL_DEPTH_8U, 3); 
             opencv_imgproc.cvCvtColor(yuvimage, rgbimage, opencv_imgproc.CV_YUV2BGR_NV21);      

             IplImage rotateimage=null;
                  try {
                        recorder.setTimestamp(videoTimestamp);   
                        int rot=0;
                        switch (degrees) {
                        case 0:
                            rot =1;
                            rotateimage=rotate(rgbimage,rot);
                        break;
                        case 180:
                            rot = -1;
                            rotateimage=rotate(rgbimage,rot);
                            break;                     
                        default:
                            rotateimage=rgbimage;
                    }                      
                        recorder.record(rotateimage);

                  } catch (FFmpegFrameRecorder.Exception e) {
                     e.printStackTrace();
                  }  
            }

        }
IplImage rotate(IplImage IplSrc,int angle) {
    IplImage img= IplImage.create(IplSrc.height(), IplSrc.width(), IplSrc.depth(), IplSrc.nChannels());
    cvTranspose(IplSrc, img);
    cvFlip(img, img, angle);        
    return img;
    }    
}