org.opencv.highgui.VideoCapture Maven / Gradle / Ivy
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// // This file is auto-generated. Please don't modify it! // package org.opencv.highgui; import java.lang.String; import org.opencv.core.Mat; // C++: class VideoCapture /** *
* *Class for video capturing from video files or cameras. * The class provides C++ API for capturing video from cameras or for reading * video files. Here is how the class can be used:
* *#include "opencv2/opencv.hpp"
* *// C++ code:
* *using namespace cv;
* *int main(int, char)
* * *VideoCapture cap(0); // open the default camera
* *if(!cap.isOpened()) // check if we succeeded
* *return -1;
* *Mat edges;
* *namedWindow("edges",1);
* *for(;;)
* * *Mat frame;
* *cap >> frame; // get a new frame from camera
* *cvtColor(frame, edges, CV_BGR2GRAY);
* *GaussianBlur(edges, edges, Size(7,7), 1.5, 1.5);
* *Canny(edges, edges, 0, 30, 3);
* *imshow("edges", edges);
* *if(waitKey(30) >= 0) break;
* * *// the camera will be deinitialized automatically in VideoCapture destructor
* *return 0;
* * *Note: In C API the black-box structure
CvCapture
is used instead * ofVideoCapture
. *Note:
*
-
*
- A basic sample on using the VideoCapture interface can be found at * opencv_source_code/samples/cpp/starter_video.cpp *
- Another basic video processing sample can be found at * opencv_source_code/samples/cpp/video_dmtx.cpp *
- (Python) A basic sample on using the VideoCapture interface can be * found at opencv_source_code/samples/python2/video.py *
- (Python) Another basic video processing sample can be found at * opencv_source_code/samples/python2/video_dmtx.py *
- (Python) A multi threaded video processing sample can be found at * opencv_source_code/samples/python2/video_threaded.py *
VideoCapture constructors.
* *Note: In C API, when you finished working with video, release
* CvCapture
structure with cvReleaseCapture()
, or use
* Ptr
that calls cvReleaseCapture()
* automatically in the destructor.
VideoCapture constructors.
* *Note: In C API, when you finished working with video, release
* CvCapture
structure with cvReleaseCapture()
, or use
* Ptr
that calls cvReleaseCapture()
* automatically in the destructor.
VideoCapture constructors.
* *Note: In C API, when you finished working with video, release
* CvCapture
structure with cvReleaseCapture()
, or use
* Ptr
that calls cvReleaseCapture()
* automatically in the destructor.
Returns the specified VideoCapture
property
Note: When querying a property that is not supported by the backend used by
* the VideoCapture
class, value 0 is returned.
-
*
- CV_CAP_PROP_POS_MSEC Current position of the video file in * milliseconds or video capture timestamp. *
- CV_CAP_PROP_POS_FRAMES 0-based index of the frame to be * decoded/captured next. *
- CV_CAP_PROP_POS_AVI_RATIO Relative position of the video file: 0 - * start of the film, 1 - end of the film. *
- CV_CAP_PROP_FRAME_WIDTH Width of the frames in the video stream. *
- CV_CAP_PROP_FRAME_HEIGHT Height of the frames in the video stream. *
- CV_CAP_PROP_FPS Frame rate. *
- CV_CAP_PROP_FOURCC 4-character code of codec. *
- CV_CAP_PROP_FRAME_COUNT Number of frames in the video file. *
- CV_CAP_PROP_FORMAT Format of the Mat objects returned by
*
retrieve()
. * - CV_CAP_PROP_MODE Backend-specific value indicating the current capture * mode. *
- CV_CAP_PROP_BRIGHTNESS Brightness of the image (only for cameras). *
- CV_CAP_PROP_CONTRAST Contrast of the image (only for cameras). *
- CV_CAP_PROP_SATURATION Saturation of the image (only for cameras). *
- CV_CAP_PROP_HUE Hue of the image (only for cameras). *
- CV_CAP_PROP_GAIN Gain of the image (only for cameras). *
- CV_CAP_PROP_EXPOSURE Exposure (only for cameras). *
- CV_CAP_PROP_CONVERT_RGB Boolean flags indicating whether images should * be converted to RGB. *
- CV_CAP_PROP_WHITE_BALANCE Currently not supported *
- CV_CAP_PROP_RECTIFICATION Rectification flag for stereo cameras (note: * only supported by DC1394 v 2.x backend currently) *
Grabs the next frame from video file or capturing device.
* *The methods/functions grab the next frame from video file or camera and * return true (non-zero) in the case of success.
* *The primary use of the function is in multi-camera environments, especially
* when the cameras do not have hardware synchronization. That is, you call
* VideoCapture.grab()
for each camera and after that call the
* slower method VideoCapture.retrieve()
to decode and get frame
* from each camera. This way the overhead on demosaicing or motion jpeg
* decompression etc. is eliminated and the retrieved frames from different
* cameras will be closer in time.
Also, when a connected camera is multi-head (for example, a stereo camera or
* a Kinect device), the correct way of retrieving data from it is to call
* "VideoCapture.grab" first and then call "VideoCapture.retrieve" one or more
* times with different values of the channel
parameter. See
* https://github.com/Itseez/opencv/tree/master/samples/cpp/openni_capture.cpp
Returns true if video capturing has been initialized already.
* *If the previous call to VideoCapture
constructor or
* VideoCapture.open
succeeded, the method returns true.
Open video file or a capturing device for video capturing
* *The methods first call "VideoCapture.release" to close the already opened * file or camera.
* * @param filename name of the opened video file (eg. video.avi) or image * sequence (eg. img_%02d.jpg, which will read samples like img_00.jpg, * img_01.jpg, img_02.jpg,...) * * @see org.opencv.highgui.VideoCapture.open */ public boolean open(String filename) { boolean retVal = open_0(nativeObj, filename); return retVal; } // // C++: bool VideoCapture::open(int device) // /** *Open video file or a capturing device for video capturing
* *The methods first call "VideoCapture.release" to close the already opened * file or camera.
* * @param device id of the opened video capturing device (i.e. a camera index). * * @see org.opencv.highgui.VideoCapture.open */ public boolean open(int device) { boolean retVal = open_1(nativeObj, device); return retVal; } // // C++: bool VideoCapture::read(Mat& image) // /** *Grabs, decodes and returns the next video frame.
* *The methods/functions combine "VideoCapture.grab" and "VideoCapture.retrieve" * in one call. This is the most convenient method for reading video files or * capturing data from decode and return the just grabbed frame. If no frames * has been grabbed (camera has been disconnected, or there are no more frames * in video file), the methods return false and the functions return NULL * pointer.
* *Note: OpenCV 1.x functions cvRetrieveFrame
and cv.RetrieveFrame
* return image stored inside the video capturing structure. It is not allowed
* to modify or release the image! You can copy the frame using "cvCloneImage"
* and then do whatever you want with the copy.
Closes video file or capturing device.
* *The methods are automatically called by subsequent "VideoCapture.open" and
* by VideoCapture
destructor.
The C function also deallocates memory and clears *capture
* pointer.
Decodes and returns the grabbed video frame.
* *The methods/functions decode and return the just grabbed frame. If no frames * has been grabbed (camera has been disconnected, or there are no more frames * in video file), the methods return false and the functions return NULL * pointer.
* *Note: OpenCV 1.x functions cvRetrieveFrame
and cv.RetrieveFrame
* return image stored inside the video capturing structure. It is not allowed
* to modify or release the image! You can copy the frame using "cvCloneImage"
* and then do whatever you want with the copy.
Decodes and returns the grabbed video frame.
* *The methods/functions decode and return the just grabbed frame. If no frames * has been grabbed (camera has been disconnected, or there are no more frames * in video file), the methods return false and the functions return NULL * pointer.
* *Note: OpenCV 1.x functions cvRetrieveFrame
and cv.RetrieveFrame
* return image stored inside the video capturing structure. It is not allowed
* to modify or release the image! You can copy the frame using "cvCloneImage"
* and then do whatever you want with the copy.
Sets a property in the VideoCapture
.
-
*
- CV_CAP_PROP_POS_MSEC Current position of the video file in * milliseconds. *
- CV_CAP_PROP_POS_FRAMES 0-based index of the frame to be * decoded/captured next. *
- CV_CAP_PROP_POS_AVI_RATIO Relative position of the video file: 0 - * start of the film, 1 - end of the film. *
- CV_CAP_PROP_FRAME_WIDTH Width of the frames in the video stream. *
- CV_CAP_PROP_FRAME_HEIGHT Height of the frames in the video stream. *
- CV_CAP_PROP_FPS Frame rate. *
- CV_CAP_PROP_FOURCC 4-character code of codec. *
- CV_CAP_PROP_FRAME_COUNT Number of frames in the video file. *
- CV_CAP_PROP_FORMAT Format of the Mat objects returned by
*
retrieve()
. * - CV_CAP_PROP_MODE Backend-specific value indicating the current capture * mode. *
- CV_CAP_PROP_BRIGHTNESS Brightness of the image (only for cameras). *
- CV_CAP_PROP_CONTRAST Contrast of the image (only for cameras). *
- CV_CAP_PROP_SATURATION Saturation of the image (only for cameras). *
- CV_CAP_PROP_HUE Hue of the image (only for cameras). *
- CV_CAP_PROP_GAIN Gain of the image (only for cameras). *
- CV_CAP_PROP_EXPOSURE Exposure (only for cameras). *
- CV_CAP_PROP_CONVERT_RGB Boolean flags indicating whether images should * be converted to RGB. *
- CV_CAP_PROP_WHITE_BALANCE Currently unsupported *
- CV_CAP_PROP_RECTIFICATION Rectification flag for stereo cameras (note: * only supported by DC1394 v 2.x backend currently) *