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mrpt::hwdrivers::CFFMPEG_InputStream Class Reference

Detailed Description

A generic class which process a video file or other kind of input stream (http, rtsp) and allows the extraction of images frame by frame.

Video sources can be open with "openURL", which can manage both video files and "rtsp://" sources (IP cameras).

Frames are retrieved by calling CFFMPEG_InputStream::retrieveFrame

For an example of usage, see the file "samples/grab_camera_ffmpeg"

Note
This class is an easy to use C++ wrapper for ffmpeg libraries (libavcodec). In Unix systems these libraries must be installed in the system as explained in MRPT's wiki. In Win32, a precompiled version for Visual Studio must be also downloaded as explained in the wiki.

Definition at line 42 of file CFFMPEG_InputStream.h.

#include <mrpt/hwdrivers/CFFMPEG_InputStream.h>

Classes

struct  Impl
 

Public Member Functions

 CFFMPEG_InputStream ()
 Default constructor, does not open any video source at startup. More...
 
virtual ~CFFMPEG_InputStream ()
 Destructor. More...
 
bool openURL (const std::string &url, bool grab_as_grayscale=false, bool verbose=false)
 Open a video file or a video stream (rtsp://) This can be used to open local video files (eg. More...
 
bool isOpen () const
 Return whether the video source was open correctly. More...
 
void close ()
 Close the video stream (this is called automatically at destruction). More...
 
double getVideoFPS () const
 Get the frame-per-second (FPS) of the video source, or "-1" if the video is not open. More...
 
bool retrieveFrame (mrpt::img::CImage &out_img)
 Get the next frame from the video stream. More...
 

Private Attributes

mrpt::pimpl< Implm_impl
 
std::string m_url
 The open URL. More...
 
bool m_grab_as_grayscale
 

Constructor & Destructor Documentation

◆ CFFMPEG_InputStream()

CFFMPEG_InputStream::CFFMPEG_InputStream ( )

Default constructor, does not open any video source at startup.

Definition at line 67 of file CFFMPEG_InputStream.cpp.

◆ ~CFFMPEG_InputStream()

CFFMPEG_InputStream::~CFFMPEG_InputStream ( )
virtual

Destructor.

Definition at line 93 of file CFFMPEG_InputStream.cpp.

References close().

Member Function Documentation

◆ close()

void CFFMPEG_InputStream::close ( )

Close the video stream (this is called automatically at destruction).

See also
openURL

Definition at line 283 of file CFFMPEG_InputStream.cpp.

References isOpen(), and m_impl.

Referenced by openURL(), mrpt::hwdrivers::CRovio::thread_video(), and ~CFFMPEG_InputStream().

◆ getVideoFPS()

double CFFMPEG_InputStream::getVideoFPS ( ) const

Get the frame-per-second (FPS) of the video source, or "-1" if the video is not open.

Definition at line 433 of file CFFMPEG_InputStream.cpp.

References isOpen(), and m_impl.

◆ isOpen()

bool CFFMPEG_InputStream::isOpen ( ) const

Return whether the video source was open correctly.

Definition at line 105 of file CFFMPEG_InputStream.cpp.

References m_impl.

Referenced by close(), getVideoFPS(), and retrieveFrame().

◆ openURL()

bool CFFMPEG_InputStream::openURL ( const std::string url,
bool  grab_as_grayscale = false,
bool  verbose = false 
)

Open a video file or a video stream (rtsp://) This can be used to open local video files (eg.

"myVideo.avi", "c:\a.mpeg") and also IP cameras (e. "rtsp://a.b.c.d/live.sdp"). However, note that there is currently no support for user/password in IP access. If verbose is set to true, more information about the video will be dumped to cout.

See also
close, retrieveFrame
Returns
false on any error (and error info dumped to cerr), true on success.

Definition at line 118 of file CFFMPEG_InputStream.cpp.

References close(), m_grab_as_grayscale, m_impl, m_url, and url.

Referenced by mrpt::hwdrivers::CRovio::thread_video().

◆ retrieveFrame()

bool CFFMPEG_InputStream::retrieveFrame ( mrpt::img::CImage out_img)

Get the next frame from the video stream.

Note that for remote streams (IP cameras) this method may block until enough information is read to generate a new frame. Images are returned as 8-bit depth grayscale if "grab_as_grayscale" is true.

Returns
false on any error, true on success.
See also
openURL, close, isOpen

Definition at line 342 of file CFFMPEG_InputStream.cpp.

References isOpen(), mrpt::img::CImage::loadFromMemoryBuffer(), m_grab_as_grayscale, m_impl, and THROW_EXCEPTION.

Referenced by mrpt::hwdrivers::CRovio::thread_video().

Member Data Documentation

◆ m_grab_as_grayscale

bool mrpt::hwdrivers::CFFMPEG_InputStream::m_grab_as_grayscale
private

Definition at line 50 of file CFFMPEG_InputStream.h.

Referenced by openURL(), and retrieveFrame().

◆ m_impl

mrpt::pimpl<Impl> mrpt::hwdrivers::CFFMPEG_InputStream::m_impl
private

Definition at line 46 of file CFFMPEG_InputStream.h.

Referenced by close(), getVideoFPS(), isOpen(), openURL(), and retrieveFrame().

◆ m_url

std::string mrpt::hwdrivers::CFFMPEG_InputStream::m_url
private

The open URL.

Definition at line 49 of file CFFMPEG_InputStream.h.

Referenced by openURL().




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