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 37 of file CFFMPEG_InputStream.h.

#include <mrpt/hwdrivers/CFFMPEG_InputStream.h>

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::utils::CImage &out_img)
	Get the next frame from the video stream. More...

Private Attributes
mrpt::utils::void_ptr_noncopy	m_state
	The internal ffmpeg state. More...
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 66 of file CFFMPEG_InputStream.cpp.

References m_state, MY_FFMPEG_STATE, mrpt::utils::non_copiable_ptr_basic< T >::set(), and THROW_EXCEPTION.

~CFFMPEG_InputStream()

CFFMPEG_InputStream::~CFFMPEG_InputStream ( )

virtual

Destructor.

Definition at line 90 of file CFFMPEG_InputStream.cpp.

References close(), m_state, MY_FFMPEG_STATE, and mrpt::utils::non_copiable_ptr_basic< T >::set().

Member Function Documentation

close()

void CFFMPEG_InputStream::close

(

)

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

See also

openURL

Definition at line 263 of file CFFMPEG_InputStream.cpp.

References isOpen(), and MY_FFMPEG_STATE.

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 412 of file CFFMPEG_InputStream.cpp.

References isOpen(), and MY_FFMPEG_STATE.

isOpen()

bool CFFMPEG_InputStream::isOpen

(

)

const

Return whether the video source was open correctly.

Definition at line 105 of file CFFMPEG_InputStream.cpp.

References MY_FFMPEG_STATE.

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_url, and MY_FFMPEG_STATE.

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

retrieveFrame()

bool CFFMPEG_InputStream::retrieveFrame

(

mrpt::utils::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 322 of file CFFMPEG_InputStream.cpp.

References isOpen(), mrpt::utils::CImage::loadFromMemoryBuffer(), m_grab_as_grayscale, MY_FFMPEG_STATE, 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 42 of file CFFMPEG_InputStream.h.

Referenced by openURL(), and retrieveFrame().

m_state

mrpt::utils::void_ptr_noncopy mrpt::hwdrivers::CFFMPEG_InputStream::m_state

private

The internal ffmpeg state.

Definition at line 40 of file CFFMPEG_InputStream.h.

Referenced by CFFMPEG_InputStream(), and ~CFFMPEG_InputStream().

m_url

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

private

The open URL.

Definition at line 41 of file CFFMPEG_InputStream.h.

Referenced by openURL().