gistfile1.txt

String fileName = Environment.getExternalStorageDirectory().toString() + "/DCIM/videosample/sample.mp4";
Log.i(TAG, "fileName="+fileName);
String aviFileName = Environment.getExternalStorageDirectory().toString() + "/DCIM/videosample/video_out.avi";
Log.i(TAG, "aviFileName="+aviFileName);

int rc = FFmpeg.execute("-i " + fileName + " -vcodec mjpeg  " + aviFileName);

if(rc == RETURN_CODE_SUCCESS){
    Log.i(TAG,"Success");
}else if(rc == RETURN_CODE_CANCEL){
    Log.i(TAG, "CANCEL");
}else {
    Log.i(TAG,String.format("Command execute failed with rc=%d and the output below.", rc));
}

VideoCapture cap = new VideoCapture();
cap.open(aviFileName);

Mat frame = new Mat();
int frameCount = 0;

if(cap.isOpened()){
    Log.d(TAG,"Video Open");

    while (true){
        Log.d(TAG,"frameCount = " + frameCount);
        cap.read(frame);
        Imgcodecs.imwrite( Environment.getExternalStorageDirectory().toString() + "/DCIM/videosample/image_output_"+ frameCount + ".jpeg",frame);
        frameCount++;
        if(frameCount == 25){
            break;
        }
    }

}else {
    Log.d("VIDEOCAPTURE","Video Open FAILED");
}