ViSP  2.8.0
Public Member Functions | Public Attributes | Protected Attributes | List of all members
vpVideoReader Class Reference

#include <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 () const
 
long getFrameIndex () const
 
long getLastFrameIndex () const
 
void open (vpImage< vpRGBa > &I)
 
void open (vpImage< unsigned char > &I)
 
void resetFrameCounter ()
 
void setFileName (const char *filename)
 
void setFileName (const std::string &filename)
 
void setFirstFrameIndex (const long firstFrame)
 
void setLastFrameIndex (const long lastFrame)
 
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.

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

#include <visp/vpDisplayX.h>
#include <visp/vpVideoReader.h>
int main()
{
#ifdef VISP_HAVE_FFMPEG
vpImage<unsigned char> I;
vpVideoReader g;
g.setFileName("./video.mpg");
g.open(I);
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);
#else
std::cout << "No image viewer is available..." << std::endl;
#endif
vpDisplay::setTitle(I, "Video grabber");
while (! g.end() ) {
double t = vpTime::measureTimeMs();
g.acquire(I);
vpDisplay::display(I);
vpDisplay::flush(I);
if (vpDisplay::getClick(I, false)) break;
vpTime::wait(t, 1000. / g.getFramerate());
}
#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 <visp/vpImage.h>
#include <visp/vpRGBa.h>
#include <visp/vpVideoReader.h>
int main()
{
#ifdef VISP_HAVE_FFMPEG
vpImage<vpRGBa> I;
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() it is also possible to set the first and last image numbers.

#include <visp/vpImage.h>
#include <visp/vpRGBa.h>
#include <visp/vpVideoReader.h>
int main()
{
vpImage<vpRGBa> I;
vpVideoReader reader;
// Initialize the reader.
reader.setFileName("./image/image%04d.jpeg");
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 <visp/vpImage.h>
#include <visp/vpRGBa.h>
#include <visp/vpVideoReader.h>
int main()
{
vpImage<vpRGBa> I;
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, mbtEdgeKltTracking.cpp, mbtEdgeTracking.cpp, mbtKltTracking.cpp, trackMeNurbs.cpp, tutorial-grabber-video.cpp, tutorial-klt-tracker.cpp, and videoReader.cpp.

Definition at line 152 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 76 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 priviously, 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, mbtEdgeKltTracking.cpp, mbtEdgeTracking.cpp, mbtKltTracking.cpp, tutorial-grabber-video.cpp, tutorial-klt-tracker.cpp, and videoReader.cpp.

Definition at line 287 of file vpVideoReader.cpp.

References vpDiskGrabber::acquire(), vpFFMPEG::acquire(), and open().

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 312 of file vpVideoReader.cpp.

References vpDiskGrabber::acquire(), vpFFMPEG::acquire(), and open().

void vpVideoReader::close ( )
inlinevirtual

This virtual function is used to de-allocate the memory used by a specific frame grabber

Implements vpFrameGrabber.

Examples:
AROgre.cpp, AROgreBasic.cpp, mbtEdgeKltTracking.cpp, mbtEdgeTracking.cpp, and mbtKltTracking.cpp.

Definition at line 207 of file vpVideoReader.h.

bool vpVideoReader::end ( void  )
inline
Returns
true if the end of the sequence is reached.
Examples:
AROgre.cpp, AROgreBasic.cpp, mbtEdgeKltTracking.cpp, mbtEdgeTracking.cpp, mbtKltTracking.cpp, tutorial-grabber-video.cpp, and tutorial-klt-tracker.cpp.

Definition at line 212 of file vpVideoReader.h.

bool vpVideoReader::getFrame ( vpImage< vpRGBa > &  I,
long  frame 
)

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: 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, trackMeNurbs.cpp, and videoReader.cpp.

Definition at line 341 of file vpVideoReader.cpp.

References vpDiskGrabber::acquire(), vpFFMPEG::getFrame(), and vpERROR_TRACE.

Referenced by open().

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

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: 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 382 of file vpVideoReader.cpp.

References vpDiskGrabber::acquire(), vpFFMPEG::getFrame(), and vpERROR_TRACE.

long vpVideoReader::getFrameIndex ( ) const
inline

Get the current frame index. 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.

Definition at line 228 of file vpVideoReader.h.

double vpVideoReader::getFramerate ( ) const

Return the framerate in Hz used to encode the video stream.

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

Examples:
tutorial-grabber-video.cpp.

Definition at line 551 of file vpVideoReader.cpp.

References vpFFMPEG::getFramerate().

unsigned int vpFrameGrabber::getHeight ( ) const
inlineinherited

Return the number of rows in the image.

Examples:
AROgre.cpp, AROgreBasic.cpp, HelloWorldOgre.cpp, and HelloWorldOgreAdvanced.cpp.

Definition at line 119 of file vpFrameGrabber.h.

Referenced by vp1394Grabber::acquire(), and vp1394Grabber::open().

long vpVideoReader::getLastFrameIndex ( ) const
inline

Gets the last frame index.

Returns
Returns the last frame index.
Examples:
imageSequenceReader.cpp, and videoReader.cpp.

Definition at line 235 of file vpVideoReader.h.

unsigned int vpFrameGrabber::getWidth ( ) const
inlineinherited

Return the number of columns in the image.

Examples:
AROgre.cpp, AROgreBasic.cpp, HelloWorldOgre.cpp, and HelloWorldOgreAdvanced.cpp.

Definition at line 121 of file vpFrameGrabber.h.

Referenced by vp1394Grabber::acquire(), and vp1394Grabber::open().

void vpVideoReader::open ( vpImage< vpRGBa > &  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.

Examples:
AROgre.cpp, AROgreBasic.cpp, imageSequenceReader.cpp, mbtEdgeKltTracking.cpp, mbtEdgeTracking.cpp, mbtKltTracking.cpp, trackMeNurbs.cpp, tutorial-grabber-video.cpp, and videoReader.cpp.

Definition at line 136 of file vpVideoReader.cpp.

References vpFFMPEG::COLORED, vpException::fatalError, getFrame(), vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), vpFrameGrabber::height, vpFFMPEG::initStream(), vpException::ioError, vpImageException::noFileNameError, vpFFMPEG::openStream(), vpDiskGrabber::setGenericName(), vpDiskGrabber::setImageNumber(), vpERROR_TRACE, and vpFrameGrabber::width.

Referenced by acquire().

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 211 of file vpVideoReader.cpp.

References vpException::fatalError, getFrame(), vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), vpFFMPEG::GRAY_SCALED, vpFrameGrabber::height, vpFFMPEG::initStream(), vpException::ioError, vpImageException::noFileNameError, vpFFMPEG::openStream(), vpDiskGrabber::setGenericName(), vpDiskGrabber::setImageNumber(), vpERROR_TRACE, and vpFrameGrabber::width.

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 246 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 exemple, 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, mbtEdgeKltTracking.cpp, mbtEdgeTracking.cpp, mbtKltTracking.cpp, trackMeNurbs.cpp, tutorial-grabber-video.cpp, tutorial-klt-tracker.cpp, and videoReader.cpp.

Definition at line 100 of file vpVideoReader.cpp.

References 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 exemple, 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 124 of file vpVideoReader.cpp.

References setFileName().

void vpVideoReader::setFirstFrameIndex ( const long  firstFrame)
inline

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

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

Definition at line 257 of file vpVideoReader.h.

void vpVideoReader::setLastFrameIndex ( const long  lastFrame)
inline

Enables to set the last frame index.

Parameters
lastFrame: The last frame index.
See also
setFirstFrameIndex()

Definition at line 268 of file vpVideoReader.h.

Member Data Documentation

unsigned int vpFrameGrabber::height
protectedinherited

Number of rows in the image.

Definition at line 113 of file vpFrameGrabber.h.

Referenced by vpDiskGrabber::acquire(), vpV4l2Grabber::acquire(), vp1394TwoGrabber::acquire(), vp1394TwoGrabber::dequeue(), vp1394Grabber::getHeight(), vp1394TwoGrabber::getHeight(), vpDiskGrabber::open(), vpV4l2Grabber::open(), open(), vp1394CMUGrabber::open(), vpOpenCVGrabber::setHeight(), vpV4l2Grabber::setHeight(), vp1394CMUGrabber::setVideoMode(), vp1394TwoGrabber::setVideoMode(), vp1394CMUGrabber::vp1394CMUGrabber(), vp1394TwoGrabber::vp1394TwoGrabber(), vpOpenCVGrabber::vpOpenCVGrabber(), and vpV4l2Grabber::vpV4l2Grabber().

bool vpFrameGrabber::init
inherited

Set to true if the frame grabber has been initialized.

Definition at line 111 of file vpFrameGrabber.h.

Referenced by vpOpenCVGrabber::acquire(), vp1394Grabber::acquire(), vpV4l2Grabber::acquire(), vpOpenCVGrabber::close(), vp1394CMUGrabber::close(), vp1394TwoGrabber::close(), vpOpenCVGrabber::open(), vpDiskGrabber::open(), vp1394Grabber::open(), vpV4l2Grabber::open(), vp1394TwoGrabber::resetBus(), vp1394CMUGrabber::vp1394CMUGrabber(), vp1394Grabber::vp1394Grabber(), vp1394TwoGrabber::vp1394TwoGrabber(), vpDiskGrabber::vpDiskGrabber(), vpOpenCVGrabber::vpOpenCVGrabber(), and vpV4l2Grabber::vpV4l2Grabber().

unsigned int vpFrameGrabber::width
protectedinherited

Number of columns in the image.

Definition at line 114 of file vpFrameGrabber.h.

Referenced by vpDiskGrabber::acquire(), vpV4l2Grabber::acquire(), vp1394TwoGrabber::acquire(), vp1394TwoGrabber::dequeue(), vp1394Grabber::getWidth(), vp1394TwoGrabber::getWidth(), vpDiskGrabber::open(), vpV4l2Grabber::open(), open(), vp1394CMUGrabber::open(), vp1394CMUGrabber::setVideoMode(), vp1394TwoGrabber::setVideoMode(), vpOpenCVGrabber::setWidth(), vpV4l2Grabber::setWidth(), vp1394CMUGrabber::vp1394CMUGrabber(), vp1394TwoGrabber::vp1394TwoGrabber(), vpOpenCVGrabber::vpOpenCVGrabber(), and vpV4l2Grabber::vpV4l2Grabber().