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Doxygen documentation for: highgui, video, imgcodecs and videoio

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This commit is contained in:
Maksim Shabunin
2014-11-19 11:29:31 +03:00
parent 1f43999f2a
commit dcae7698ad
12 changed files with 1386 additions and 54 deletions
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237
modules/videoio/include/opencv2/videoio.hpp
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@@ -45,6 +45,13 @@
#include "opencv2/core.hpp"
/**
@defgroup videoio Media I/O
@{
@defgroup videoio_c C API
@defgroup videoio_ios iOS glue
@}
*/
////////////////////////////////// video io /////////////////////////////////
@@ -54,6 +61,9 @@ typedef struct CvVideoWriter CvVideoWriter;
namespace cv
{
//! @addtogroup videoio
//! @{
// Camera API
enum { CAP_ANY = 0, // autodetect
CAP_VFW = 200, // platform native
@@ -345,26 +355,209 @@ enum { CAP_INTELPERC_DEPTH_MAP = 0, // Each pixel is a 16-bit integ
class IVideoCapture;
/** @brief Class for video capturing from video files, image sequences or cameras. The class provides C++ API
for capturing video from cameras or for reading video files and image sequences. Here is how the
class can be used: :
@code
#include "opencv2/opencv.hpp"
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, COLOR_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;
}
@endcode
@note In C API the black-box structure CvCapture is used instead of VideoCapture.
@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
*/
class CV_EXPORTS_W VideoCapture
{
public:
/** @brief
@note In C API, when you finished working with video, release CvCapture structure with
cvReleaseCapture(), or use Ptr\<CvCapture\> that calls cvReleaseCapture() automatically in the
destructor.
*/
CV_WRAP VideoCapture();
/** @overload
@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, ...)
*/
CV_WRAP VideoCapture(const String& filename);
/** @overload
@param device id of the opened video capturing device (i.e. a camera index). If there is a single
camera connected, just pass 0.
*/
CV_WRAP VideoCapture(int device);
virtual ~VideoCapture();
/** @brief Open video file or a capturing device for video capturing
@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, ...)
The methods first call VideoCapture::release to close the already opened file or camera.
*/
CV_WRAP virtual bool open(const String& filename);
/** @overload
@param device id of the opened video capturing device (i.e. a camera index).
*/
CV_WRAP virtual bool open(int device);
/** @brief Returns true if video capturing has been initialized already.
If the previous call to VideoCapture constructor or VideoCapture::open succeeded, the method returns
true.
*/
CV_WRAP virtual bool isOpened() const;
/** @brief 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.
*/
CV_WRAP virtual void release();
/** @brief 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>
*/
CV_WRAP virtual bool grab();
/** @brief 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
:ocvcvCloneImage and then do whatever you want with the copy.
*/
CV_WRAP virtual bool retrieve(OutputArray image, int flag = 0);
virtual VideoCapture& operator >> (CV_OUT Mat& image);
virtual VideoCapture& operator >> (CV_OUT UMat& image);
/** @brief 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
:ocvcvCloneImage and then do whatever you want with the copy.
*/
CV_WRAP virtual bool read(OutputArray image);
/** @brief Sets a property in the VideoCapture.
@param propId Property identifier. It can be one of the following:
- **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)
@param value Value of the property.
*/
CV_WRAP virtual bool set(int propId, double value);
/** @brief Returns the specified VideoCapture property
@param propId Property identifier. It can be one of the following:
- **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)
**Note**: When querying a property that is not supported by the backend used by the VideoCapture
class, value 0 is returned.
*/
CV_WRAP virtual double get(int propId);
protected:
@@ -374,21 +567,63 @@ private:
static Ptr<IVideoCapture> createCameraCapture(int index);
};
/** @brief Video writer class.
*/
class CV_EXPORTS_W VideoWriter
{
public:
/** @brief VideoWriter constructors
The constructors/functions initialize video writers. On Linux FFMPEG is used to write videos; on
Windows FFMPEG or VFW is used; on MacOSX QTKit is used.
*/
CV_WRAP VideoWriter();
/** @overload
@param filename Name of the output video file.
@param fourcc 4-character code of codec used to compress the frames. For example,
VideoWriter::fourcc('P','I','M','1') is a MPEG-1 codec, VideoWriter::fourcc('M','J','P','G') is a
motion-jpeg codec etc. List of codes can be obtained at [Video Codecs by
FOURCC](http://www.fourcc.org/codecs.php) page.
@param fps Framerate of the created video stream.
@param frameSize Size of the video frames.
@param isColor If it is not zero, the encoder will expect and encode color frames, otherwise it
will work with grayscale frames (the flag is currently supported on Windows only).
*/
CV_WRAP VideoWriter(const String& filename, int fourcc, double fps,
Size frameSize, bool isColor = true);
virtual ~VideoWriter();
/** @brief Initializes or reinitializes video writer.
The method opens video writer. Parameters are the same as in the constructor
VideoWriter::VideoWriter.
*/
CV_WRAP virtual bool open(const String& filename, int fourcc, double fps,
Size frameSize, bool isColor = true);
/** @brief Returns true if video writer has been successfully initialized.
*/
CV_WRAP virtual bool isOpened() const;
CV_WRAP virtual void release();
virtual VideoWriter& operator << (const Mat& image);
/** @brief Writes the next video frame
@param image The written frame
The functions/methods write the specified image to video file. It must have the same size as has
been specified when opening the video writer.
*/
CV_WRAP virtual void write(const Mat& image);
/** @brief Concatenates 4 chars to a fourcc code
This static method constructs the fourcc code of the codec to be used in the constructor
VideoWriter::VideoWriter or VideoWriter::open.
*/
CV_WRAP static int fourcc(char c1, char c2, char c3, char c4);
protected:
@@ -398,6 +633,8 @@ protected:
template<> CV_EXPORTS void DefaultDeleter<CvCapture>::operator ()(CvCapture* obj) const;
template<> CV_EXPORTS void DefaultDeleter<CvVideoWriter>::operator ()(CvVideoWriter* obj) const;
//! @} videoio
} // cv
#endif //__OPENCV_VIDEOIO_HPP__

6
modules/videoio/include/opencv2/videoio/cap_ios.h
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@@ -32,6 +32,9 @@
#import <ImageIO/ImageIO.h>
#include "opencv2/core.hpp"
//! @addtogroup videoio_ios
//! @{
/////////////////////////////////////// CvAbstractCamera /////////////////////////////////////
@class CvAbstractCamera;
@@ -167,3 +170,6 @@
- (void)takePicture;
@end
//! @} videoio_ios

5
modules/videoio/include/opencv2/videoio/videoio_c.h
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@@ -48,6 +48,10 @@
extern "C" {
#endif /* __cplusplus */
/**
@addtogroup videoio_c
@{
*/
/****************************************************************************************\
* Working with Video Files and Cameras *
@@ -416,6 +420,7 @@ CVAPI(void) cvReleaseVideoWriter( CvVideoWriter** writer );
#define cvCreateAVIWriter cvCreateVideoWriter
#define cvWriteToAVI cvWriteFrame
/** @} videoio_c */
#ifdef __cplusplus
}