Visual Servoing Platform  version 3.2.0 under development (2018-12-17)
vpVideoReader Class Reference

#include <visp3/io/vpVideoReader.h>

+ Inheritance diagram for vpVideoReader:

Public Member Functions

 vpVideoReader ()
 
 ~vpVideoReader ()
 
void acquire (vpImage< vpRGBa > &I)
 
void acquire (vpImage< unsigned char > &I)
 
void close ()
 
bool end ()
 
bool getFrame (vpImage< vpRGBa > &I, long frame)
 
bool getFrame (vpImage< unsigned char > &I, long frame)
 
double getFramerate ()
 
long getFrameIndex () const
 
long getFirstFrameIndex ()
 
long getLastFrameIndex ()
 
long getFrameStep () const
 
void open (vpImage< vpRGBa > &I)
 
void open (vpImage< unsigned char > &I)
 
vpVideoReaderoperator>> (vpImage< unsigned char > &I)
 
vpVideoReaderoperator>> (vpImage< vpRGBa > &I)
 
void resetFrameCounter ()
 
void setFileName (const char *filename)
 
void setFileName (const std::string &filename)
 
void setFirstFrameIndex (const long first_frame)
 
void setLastFrameIndex (const long last_frame)
 
void setFrameStep (const long frame_step)
 
Inherited functionalities from vpFramegrabber
unsigned int getHeight () const
 
unsigned int getWidth () const
 

Public Attributes

bool init
 

Protected Attributes

unsigned int height
 
unsigned int width
 

Detailed Description

Class that enables to manipulate easily a video file or a sequence of images. As it inherits from the vpFrameGrabber Class, it can be used like an other frame grabber class.

This class has its own implementation to read a sequence of PGM and PPM images.

This class may benefit from optional 3rd parties:

  • libpng: If installed this optional 3rd party is used to read a sequence of PNG images. Installation instructions are provided here https://visp.inria.fr/3rd_png.
  • libjpeg: If installed this optional 3rd party is used to read a sequence of JPEG images. Installation instructions are provided here https://visp.inria.fr/3rd_jpeg.
  • OpenCV: If installed this optional 3rd party is used to read a sequence of images where images could be in TIFF, BMP, DIB, PBM, RASTER, JPEG2000 format. If libpng or libjpeg is not installed, OpenCV is also used to consider these image formats. OpenCV allows also to consider AVI, MPEG, MPEG4, MOV, OGV, WMV, FLV, MKV video formats. Installation instructions are provided here https://visp.inria.fr/3rd_opencv.

The following example available in tutorial-video-reader.cpp shows how this class is really easy to use. It enables to read a video file named video.mpeg.

#include <visp3/gui/vpDisplayGDI.h>
#include <visp3/gui/vpDisplayOpenCV.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/core/vpTime.h>
#include <visp3/io/vpVideoReader.h>
int main(int argc, char **argv)
{
#if (VISP_HAVE_OPENCV_VERSION >= 0x020100)
try {
std::string videoname = "video.mpg";
for (int i = 0; i < argc; i++) {
if (std::string(argv[i]) == "--name")
videoname = std::string(argv[i + 1]);
else if (std::string(argv[i]) == "--help" || std::string(argv[i]) == "-h") {
std::cout << "\nUsage: " << argv[0] << " [--name <video name> (default: " << videoname << ")] [--help] [-h]\n" << std::endl;
return 0;
}
}
g.setFileName(videoname);
g.open(I);
std::cout << "Video name : " << videoname << std::endl;
std::cout << "Video framerate: " << g.getFramerate() << "Hz" << std::endl;
std::cout << "Video dimension: " << I.getWidth() << " " << I.getHeight() << std::endl;
#ifdef VISP_HAVE_X11
vpDisplayX d(I);
#elif defined(VISP_HAVE_GDI)
#elif defined(VISP_HAVE_OPENCV)
#else
std::cout << "No image viewer is available..." << std::endl;
#endif
vpDisplay::setTitle(I, "Video reader");
unsigned cpt = 1;
while (!g.end()) {
double t = vpTime::measureTimeMs();
g.acquire(I);
vpDisplay::displayText(I, 20, 20, "Click to quit", vpColor::red);
std::stringstream ss;
ss << "Frame: " << cpt ++;
vpDisplay::displayText(I, 40, 20, ss.str(), vpColor::red);
if (vpDisplay::getClick(I, false))
break;
vpTime::wait(t, 1000. / g.getFramerate());
}
std::cout << "End of video was reached" << std::endl;
} catch (const vpException &e) {
std::cout << e.getMessage() << std::endl;
}
#else
(void)argc;
(void)argv;
std::cout << "Install OpenCV and rebuild ViSP to use this example." << std::endl;
#endif
}

As shown in the next example, this class allows also to access to a specific frame. But be careful, for video files, the getFrame() method is not precise and returns the nearest intra key frame from the expected frame. You can use the getFrame() method to position the reader in the video and then use the acquire() method to get the following frames one by one.

#include <visp3/io/vpVideoReader.h>
int main()
{
#ifdef VISP_HAVE_OPENCV
vpVideoReader reader;
// Initialize the reader.
reader.setFileName("video.mpeg");
reader.open(I);
// Read the nearest key frame from the 3th frame
reader.getFrame(I, 2);
// After positionning the video reader use acquire to read the video frame by frame
reader.acquire(I);
return 0;
#endif
}

The other following example explains how to use the class to read a sequence of images. The images are stored in the folder "./image" and are named "image0000.jpeg", "image0001.jpeg", "image0002.jpeg", ... As explained in setFirstFrameIndex() and setLastFrameIndex() it is also possible to set the first and last image numbers to read a portion of the sequence. If these two functions are not used, first and last image numbers are set automatically to match the first and image images of the sequence.

#include <visp3/io/vpVideoReader.h>
int main()
{
vpVideoReader reader;
// Initialize the reader.
reader.setFileName("./image/image%04d.jpeg");
reader.setFirstFrameIndex(10);
reader.setLastFrameIndex(20);
reader.open(I);
while (! reader.end() )
reader.acquire(I);
return 0;
}

Note that it is also possible to access to a specific frame using getFrame().

#include <visp3/io/vpVideoReader.h>
int main()
{
vpVideoReader reader;
// Initialize the reader.
reader.setFileName("./image/image%04d.jpeg");
reader.open(I);
// Read the 3th frame
reader.getFrame(I,2);
return 0;
}
Examples:
AROgre.cpp, AROgreBasic.cpp, imageSequenceReader.cpp, mbtEdgeKltMultiTracking.cpp, mbtEdgeKltTracking.cpp, mbtEdgeMultiTracking.cpp, mbtEdgeTracking.cpp, mbtGenericTracking.cpp, mbtGenericTracking2.cpp, mbtKltMultiTracking.cpp, mbtKltTracking.cpp, templateTracker.cpp, testImageNormalizedCorrelation.cpp, testImageTemplateMatching.cpp, testKeyPoint-2.cpp, testKeyPoint-3.cpp, testKeyPoint-4.cpp, testKeyPoint.cpp, trackMeNurbs.cpp, tutorial-chessboard-pose.cpp, tutorial-detection-object-mbt-deprecated.cpp, tutorial-detection-object-mbt.cpp, tutorial-detection-object-mbt2-deprecated.cpp, tutorial-detection-object-mbt2.cpp, tutorial-face-detector.cpp, tutorial-klt-tracker-with-reinit.cpp, tutorial-klt-tracker.cpp, tutorial-matching-keypoint-homography.cpp, tutorial-matching-keypoint-SIFT.cpp, tutorial-matching-keypoint.cpp, tutorial-matching-surf-deprecated.cpp, tutorial-matching-surf-homography-deprecated.cpp, tutorial-mb-edge-tracker.cpp, tutorial-mb-generic-tracker-full.cpp, tutorial-mb-generic-tracker-stereo-mono.cpp, tutorial-mb-generic-tracker-stereo.cpp, tutorial-mb-generic-tracker.cpp, tutorial-mb-hybrid-tracker.cpp, tutorial-mb-klt-tracker.cpp, tutorial-mb-tracker-full.cpp, tutorial-mb-tracker-stereo-mono.cpp, tutorial-mb-tracker-stereo.cpp, tutorial-mb-tracker.cpp, tutorial-template-tracker.cpp, tutorial-video-reader.cpp, and videoReader.cpp.

Definition at line 171 of file vpVideoReader.h.

Constructor & Destructor Documentation

vpVideoReader::vpVideoReader ( )

Basic constructor.

Definition at line 57 of file vpVideoReader.cpp.

vpVideoReader::~vpVideoReader ( )

Basic destructor.

Definition at line 70 of file vpVideoReader.cpp.

Member Function Documentation

void vpVideoReader::acquire ( vpImage< vpRGBa > &  I)
virtual

Grabs the current (k) image in the stack of frames and increments the frame counter in order to grab the next image (k+1) during the next use of the method. If open() was not called previously, this method opens the video reader.

This method enables to use the class as frame grabber.

Parameters
I: The image where the frame is stored.

Implements vpFrameGrabber.

Examples:
AROgre.cpp, AROgreBasic.cpp, mbtEdgeKltMultiTracking.cpp, mbtEdgeKltTracking.cpp, mbtEdgeMultiTracking.cpp, mbtEdgeTracking.cpp, mbtGenericTracking.cpp, mbtGenericTracking2.cpp, mbtKltMultiTracking.cpp, mbtKltTracking.cpp, templateTracker.cpp, testImageTemplateMatching.cpp, testKeyPoint-2.cpp, testKeyPoint-3.cpp, testKeyPoint-4.cpp, testKeyPoint.cpp, tutorial-chessboard-pose.cpp, tutorial-detection-object-mbt-deprecated.cpp, tutorial-detection-object-mbt.cpp, tutorial-detection-object-mbt2-deprecated.cpp, tutorial-detection-object-mbt2.cpp, tutorial-face-detector.cpp, tutorial-klt-tracker-with-reinit.cpp, tutorial-klt-tracker.cpp, tutorial-matching-keypoint-homography.cpp, tutorial-matching-keypoint-SIFT.cpp, tutorial-matching-keypoint.cpp, tutorial-matching-surf-deprecated.cpp, tutorial-matching-surf-homography-deprecated.cpp, tutorial-mb-edge-tracker.cpp, tutorial-mb-generic-tracker-full.cpp, tutorial-mb-generic-tracker-stereo-mono.cpp, tutorial-mb-generic-tracker-stereo.cpp, tutorial-mb-generic-tracker.cpp, tutorial-mb-hybrid-tracker.cpp, tutorial-mb-klt-tracker.cpp, tutorial-mb-tracker-full.cpp, tutorial-mb-tracker-stereo-mono.cpp, tutorial-mb-tracker-stereo.cpp, tutorial-mb-tracker.cpp, tutorial-template-tracker.cpp, tutorial-video-reader.cpp, and videoReader.cpp.

Definition at line 266 of file vpVideoReader.cpp.

References vpDiskGrabber::acquire(), vpImageConvert::convert(), vpDiskGrabber::getImageNumber(), open(), vpDiskGrabber::setImageNumber(), setLastFrameIndex(), and vpDiskGrabber::setStep().

Referenced by operator>>().

void vpVideoReader::acquire ( vpImage< unsigned char > &  I)
virtual

Grabs the kth image in the stack of frames and increments the frame counter in order to grab the next image (k+1) during the next use of the method.

This method enables to use the class as frame grabber.

Parameters
I: The image where the frame is stored.

Implements vpFrameGrabber.

Definition at line 338 of file vpVideoReader.cpp.

References vpDiskGrabber::acquire(), vpImageConvert::convert(), vpDiskGrabber::getImageNumber(), open(), vpDiskGrabber::setImageNumber(), setLastFrameIndex(), and vpDiskGrabber::setStep().

void vpVideoReader::close ( )
inlinevirtual
long vpVideoReader::getFirstFrameIndex ( )
inline
bool vpVideoReader::getFrame ( vpImage< vpRGBa > &  I,
long  frame_index 
)

Gets the $ frame $ th frame and stores it in the image $ I $.

Warning
For the video files this method is not precise, and returns the nearest key frame from the expected frame. But this method enables to position the reader where you want. Then, use the acquire method to grab the following images one after one.
Parameters
I: The vpImage used to stored the frame.
frame_index: The index of the frame which has to be read.
Returns
It returns true if the frame could be read. Else it returns false.
Examples:
imageSequenceReader.cpp, and trackMeNurbs.cpp.

Definition at line 414 of file vpVideoReader.cpp.

References vpDiskGrabber::acquire(), vpImageConvert::convert(), vpImage< Type >::getHeight(), vpDiskGrabber::getImageNumber(), vpImage< Type >::getWidth(), vpFrameGrabber::height, vpDiskGrabber::setImageNumber(), setLastFrameIndex(), vpERROR_TRACE, and vpFrameGrabber::width.

Referenced by open().

bool vpVideoReader::getFrame ( vpImage< unsigned char > &  I,
long  frame_index 
)

Gets the $ frame $ th frame and stores it in the image $ I $.

Warning
For the video files this method is not precise, and returns the nearest key frame from the expected frame. But this method enables to position the reader where you want. Then, use the acquire method to grab the following images one after one.
Parameters
I: The vpImage used to stored the frame.
frame_index: The index of the frame which has to be read.
Returns
It returns true if the frame could be read. Else it returns false.

Definition at line 484 of file vpVideoReader.cpp.

References vpDiskGrabber::acquire(), vpImageConvert::convert(), vpIoTools::getDirFiles(), vpImage< Type >::getHeight(), vpDiskGrabber::getImageNumber(), vpIoTools::getName(), vpIoTools::getParent(), vpImage< Type >::getWidth(), vpFrameGrabber::height, vpException::notInitialized, vpDiskGrabber::setImageNumber(), setLastFrameIndex(), vpERROR_TRACE, and vpFrameGrabber::width.

long vpVideoReader::getFrameIndex ( ) const
inline

Get the frame index of the current image. This index is updated at each call of the acquire method. It can be used to detect the end of a file (comparison with getLastFrameIndex()).

Returns
Returns the current frame index.
See also
end()
Examples:
imageSequenceReader.cpp, mbtEdgeKltMultiTracking.cpp, mbtEdgeKltTracking.cpp, mbtEdgeMultiTracking.cpp, mbtEdgeTracking.cpp, mbtGenericTracking.cpp, mbtGenericTracking2.cpp, mbtKltMultiTracking.cpp, mbtKltTracking.cpp, templateTracker.cpp, testImageTemplateMatching.cpp, testKeyPoint-2.cpp, testKeyPoint-4.cpp, tutorial-chessboard-pose.cpp, tutorial-klt-tracker-with-reinit.cpp, tutorial-klt-tracker.cpp, and videoReader.cpp.

Definition at line 293 of file vpVideoReader.h.

double vpVideoReader::getFramerate ( )
inline

Return the frame rate in Hz used to encode the video stream.

If the video is a sequence of images, return -1.

Examples:
tutorial-video-reader.cpp.

Definition at line 276 of file vpVideoReader.h.

long vpVideoReader::getFrameStep ( ) const
inline

Gets the frame step.

Returns
Returns the frame step value.

Definition at line 324 of file vpVideoReader.h.

References vpFrameGrabber::open().

unsigned int vpFrameGrabber::getHeight ( ) const
inlineinherited

Return the number of rows in the image.

Examples:
AROgre.cpp, AROgreBasic.cpp, and testPylonGrabber.cpp.

Definition at line 114 of file vpFrameGrabber.h.

long vpVideoReader::getLastFrameIndex ( )
inline
unsigned int vpFrameGrabber::getWidth ( ) const
inlineinherited

Return the number of columns in the image.

Examples:
AROgre.cpp, AROgreBasic.cpp, and testPylonGrabber.cpp.

Definition at line 116 of file vpFrameGrabber.h.

void vpVideoReader::open ( vpImage< unsigned char > &  I)
virtual

Sets all the parameters needed to read the video or the image sequence.

Grab the first frame and stores it in the image $ I $.

Parameters
I: The image where the frame is stored.

Implements vpFrameGrabber.

Definition at line 230 of file vpVideoReader.cpp.

References getFrame(), and vpException::ioError.

vpVideoReader & vpVideoReader::operator>> ( vpImage< unsigned char > &  I)

Operator that allows to capture a grey level image.

Parameters
I: The captured image.
#include <visp3/io/vpVideoReader.h>
int main()
{
vpVideoReader reader;
// Initialize the reader.
reader.setFileName("./image/image%04d.jpeg");
reader.setFirstFrameIndex(10);
reader.setLastFrameIndex(20);
reader.open(I);
while (! reader.end() )
reader >> I;
}

Definition at line 789 of file vpVideoReader.cpp.

References acquire().

vpVideoReader & vpVideoReader::operator>> ( vpImage< vpRGBa > &  I)

Operator that allows to capture a grey level image.

Parameters
I: The captured image.
#include <visp3/io/vpVideoReader.h>
int main()
{
vpVideoReader reader;
// Initialize the reader.
reader.setFileName("./image/image%04d.jpeg");
reader.setFirstFrameIndex(10);
reader.setLastFrameIndex(20);
reader.open(I);
while (! reader.end() )
reader >> I;
}

Definition at line 819 of file vpVideoReader.cpp.

References acquire().

void vpVideoReader::resetFrameCounter ( )
inline

Reset the frame counter and sets it to the first image index.

By default the first frame index is set to 0.

This method is useful if you use the class like a frame grabber (ie with theacquire method).

Definition at line 339 of file vpVideoReader.h.

void vpVideoReader::setFileName ( const char *  filename)

It enables to set the path and the name of the file(s) which as/have to be read.

If you want to read a video file, $ filename $ corresponds to the path to the file (example : /local/video.mpeg).

If you want to read a sequence of images, $ filename $ corresponds to the path followed by the image name template. For example, if you want to read different images named image0001.jpeg, image0002.jpg, ... and located in the folder /local/image, $ filename $ will be "/local/image/image%04d.jpg".

Parameters
filename: Path to a video file or file name template of a image sequence.
Examples:
AROgre.cpp, AROgreBasic.cpp, imageSequenceReader.cpp, mbtEdgeKltMultiTracking.cpp, mbtEdgeKltTracking.cpp, mbtEdgeMultiTracking.cpp, mbtEdgeTracking.cpp, mbtGenericTracking.cpp, mbtGenericTracking2.cpp, mbtKltMultiTracking.cpp, mbtKltTracking.cpp, templateTracker.cpp, testImageNormalizedCorrelation.cpp, testImageTemplateMatching.cpp, testKeyPoint-2.cpp, testKeyPoint-3.cpp, testKeyPoint-4.cpp, testKeyPoint.cpp, trackMeNurbs.cpp, tutorial-chessboard-pose.cpp, tutorial-detection-object-mbt-deprecated.cpp, tutorial-detection-object-mbt.cpp, tutorial-detection-object-mbt2-deprecated.cpp, tutorial-detection-object-mbt2.cpp, tutorial-face-detector.cpp, tutorial-klt-tracker-with-reinit.cpp, tutorial-klt-tracker.cpp, tutorial-matching-keypoint-homography.cpp, tutorial-matching-keypoint-SIFT.cpp, tutorial-matching-keypoint.cpp, tutorial-matching-surf-deprecated.cpp, tutorial-matching-surf-homography-deprecated.cpp, tutorial-mb-edge-tracker.cpp, tutorial-mb-generic-tracker-full.cpp, tutorial-mb-generic-tracker-stereo-mono.cpp, tutorial-mb-generic-tracker-stereo.cpp, tutorial-mb-generic-tracker.cpp, tutorial-mb-hybrid-tracker.cpp, tutorial-mb-klt-tracker.cpp, tutorial-mb-tracker-full.cpp, tutorial-mb-tracker-stereo-mono.cpp, tutorial-mb-tracker-stereo.cpp, tutorial-mb-tracker.cpp, tutorial-template-tracker.cpp, tutorial-video-reader.cpp, and videoReader.cpp.

Definition at line 92 of file vpVideoReader.cpp.

References vpException::badValue, vpIoTools::getName(), vpException::memoryAllocationError, vpImageException::noFileNameError, and vpERROR_TRACE.

Referenced by setFileName().

void vpVideoReader::setFileName ( const std::string &  filename)

It enables to set the path and the name of the file(s) which as/have to be read.

If you want to read a video file, $ filename $ corresponds to the path to the file (example : /local/video.mpeg).

If you want to read a sequence of images, $ filename $ corresponds to the path followed by the image name template. For example, if you want to read different images named image0001.jpeg, image0002.jpg, ... and located in the folder /local/image, $ filename $ will be "/local/image/image%04d.jpg".

Parameters
filename: Path to a video file or file name template of a image sequence.

Definition at line 137 of file vpVideoReader.cpp.

References vpException::fatalError, vpFrameGrabber::height, vpException::ioError, vpImageException::noFileNameError, setFileName(), vpDiskGrabber::setGenericName(), vpDiskGrabber::setImageNumber(), vpDiskGrabber::setStep(), and vpFrameGrabber::width.

void vpVideoReader::setFirstFrameIndex ( const long  first_frame)
inline

Enables to set the first frame index if you want to use the class like a grabber (ie with the acquire method).

Parameters
first_frame: The first frame index.
See also
setLastFrameIndex()
Examples:
AROgre.cpp, AROgreBasic.cpp, imageSequenceReader.cpp, templateTracker.cpp, and trackMeNurbs.cpp.

Definition at line 350 of file vpVideoReader.h.

void vpVideoReader::setFrameStep ( const long  frame_step)
inline

Sets the frame step index. The default frame step is 1

Parameters
frame_step: The frame index step.
See also
setFrameStep()

Definition at line 376 of file vpVideoReader.h.

void vpVideoReader::setLastFrameIndex ( const long  last_frame)
inline

Enables to set the last frame index.

Parameters
last_frame: The last frame index.
See also
setFirstFrameIndex()
Examples:
mbtEdgeKltMultiTracking.cpp, mbtEdgeKltTracking.cpp, mbtEdgeMultiTracking.cpp, mbtEdgeTracking.cpp, mbtGenericTracking.cpp, mbtGenericTracking2.cpp, mbtKltMultiTracking.cpp, mbtKltTracking.cpp, and templateTracker.cpp.

Definition at line 362 of file vpVideoReader.h.

Referenced by acquire(), and getFrame().

Member Data Documentation