ViSP  2.8.0
Public Member Functions | List of all members
vpVideoWriter Class Reference

#include <vpVideoWriter.h>

Public Member Functions

 vpVideoWriter ()
 
 ~vpVideoWriter ()
 
void close ()
 
unsigned int getCurrentFrameIndex () const
 
void open (vpImage< vpRGBa > &I)
 
void open (vpImage< unsigned char > &I)
 
void resetFrameCounter ()
 
void saveFrame (vpImage< vpRGBa > &I)
 
void saveFrame (vpImage< unsigned char > &I)
 
void setBitRate (const unsigned int bit_rate)
 
void setCodec (const AVCodecID codec)
 
void setFileName (const char *filename)
 
void setFileName (const std::string &filename)
 
void setFirstFrameIndex (const unsigned int firstFrame)
 
void setFramerate (const int framerate)
 

Detailed Description

Class that enables to write easily a video file or a sequence of images.

The following example shows how this class is really easy to use. It enable to write an image sequence. The images are stored in the folder "./image" and are named "image0000.jpeg", "image0001.jpeg", "image0002.jpeg", ...

#include <visp/vpConfig.h>
#include <visp/vpVideoWriter.h>
int main()
{
vpImage<vpRGBa> I;
vpVideoWriter writer;
//Initialize the writer.
writer.setFileName("./image/image%04d.jpeg");
writer.open(I);
for ( ; ; )
{
//Here the code to capture or create an image and stores it in I.
//Save the image
writer.saveFrame(I);
}
writer.close();
return 0;
}

The other following example explains how to use the class to write directly an mpeg file.

#include <visp/vpVideoWriter.h>
int main()
{
#ifdef VISP_HAVE_FFMPEG
vpImage<vpRGBa> I;
vpVideoWriter writer;
// Set up the framerate to 30Hz. Default is 25Hz.
writer.setFramerate(30);
// Set up the bit rate
writer.setBitRate(1000000);
// Set up the codec to use
#if LIBAVCODEC_VERSION_INT < AV_VERSION_INT(54,51,110) // libavcodec 54.51.100
writer.setCodec(CODEC_ID_MPEG2VIDEO);
#else
writer.setCodec(AV_CODEC_ID_MPEG2VIDEO);
#endif
writer.setFileName("./test.mpeg");
writer.open(I);
for ( ; ; )
{
// Here the code to capture or create an image and store it in I.
// Save the image
writer.saveFrame(I);
}
writer.close();
return 0;
#endif
}

Definition at line 135 of file vpVideoWriter.h.

Constructor & Destructor Documentation

vpVideoWriter::vpVideoWriter ( )

Basic constructor.

Definition at line 54 of file vpVideoWriter.cpp.

vpVideoWriter::~vpVideoWriter ( )

Basic destructor.

Definition at line 76 of file vpVideoWriter.cpp.

Member Function Documentation

void vpVideoWriter::close ( )

Deallocates parameters use to write the video or the image sequence.

Definition at line 297 of file vpVideoWriter.cpp.

References vpFFMPEG::endWrite(), vpException::notInitialized, and vpERROR_TRACE.

unsigned int vpVideoWriter::getCurrentFrameIndex ( ) const
inline

Gets the current frame index.

Returns
Returns the current frame index.

Definition at line 197 of file vpVideoWriter.h.

void vpVideoWriter::open ( vpImage< vpRGBa > &  I)

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

Parameters
I: One image with the right dimensions.

Definition at line 124 of file vpVideoWriter.cpp.

References vpException::fatalError, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), vpException::ioError, vpImageException::noFileNameError, vpFFMPEG::openEncoder(), vpFFMPEG::setBitRate(), vpFFMPEG::setFramerate(), and vpERROR_TRACE.

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

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

Parameters
I: One image with the right dimensions.

Definition at line 173 of file vpVideoWriter.cpp.

References vpException::fatalError, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), vpException::ioError, vpImageException::noFileNameError, vpFFMPEG::openEncoder(), vpFFMPEG::setBitRate(), vpFFMPEG::setFramerate(), and vpERROR_TRACE.

void vpVideoWriter::resetFrameCounter ( )
inline

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

By default the first frame index is set to 0.

Definition at line 206 of file vpVideoWriter.h.

void vpVideoWriter::saveFrame ( vpImage< vpRGBa > &  I)

Saves the image as a frame of the video or as an image belonging to the image sequence.

Each time this method is used, the frame counter is incremented and thus the file name change for the case of an image sequence.

Parameters
I: The image which has to be saved

Definition at line 224 of file vpVideoWriter.cpp.

References vpException::notInitialized, vpFFMPEG::saveFrame(), vpERROR_TRACE, and vpImageIo::write().

void vpVideoWriter::saveFrame ( vpImage< unsigned char > &  I)

Saves the image as a frame of the video or as an image belonging to the image sequence.

Each time this method is used, the frame counter is incremented and thus the file name change for the case of an image sequence.

Parameters
I: The image which has to be saved

Definition at line 263 of file vpVideoWriter.cpp.

References vpException::notInitialized, vpFFMPEG::saveFrame(), vpERROR_TRACE, and vpImageIo::write().

void vpVideoWriter::setBitRate ( const unsigned int  bit_rate)
inline

Sets the bit rate of the video when encoding.

Parameters
bit_rate: the expected bit rate.

By default the bit rate is set to 500 000.

Definition at line 219 of file vpVideoWriter.h.

void vpVideoWriter::setCodec ( const AVCodecID  codec)
inline

Sets the codec used to encode the video.

Parameters
codec: the expected codec.

By default codec is set to AV_CODEC_ID_MPEG1VIDEO. But if installed, you can use one of the AVCodecID proposed by ffmpeg such as : AV_CODEC_ID_MPEG2VIDEO, AV_CODEC_ID_MPEG2VIDEO_XVMC, AV_CODEC_ID_MPEG4, AV_CODEC_ID_H264, ... (More AVCodecID can be found in the ffmpeg documentation).

Of course to use the codec it must be installed on your computer.

Definition at line 235 of file vpVideoWriter.h.

void vpVideoWriter::setFileName ( const char *  filename)

It enables to set the path and the name of the files which will be saved.

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

Parameters
filename: filename template of an image sequence.

Definition at line 92 of file vpVideoWriter.cpp.

References vpImageException::noFileNameError, and vpERROR_TRACE.

Referenced by setFileName().

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

It enables to set the path and the name of the files which will be saved.

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

Parameters
filename: filename template of an image sequence.

Definition at line 114 of file vpVideoWriter.cpp.

References setFileName().

void vpVideoWriter::setFirstFrameIndex ( const unsigned int  firstFrame)
inline

Enables to set the first frame index.

Parameters
firstFrame: The first frame index.

Definition at line 246 of file vpVideoWriter.h.

void vpVideoWriter::setFramerate ( const int  framerate)
inline

Sets the framerate in Hz of the video when encoding.

Parameters
framerate: the expected framerate.

By default the framerate is set to 25Hz.

Definition at line 255 of file vpVideoWriter.h.