CFFMPEG_InputStream.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#ifndef CFFMPEG_InputStream_H
#define CFFMPEG_InputStream_H

#include <mrpt/utils/utils_defs.h>
#include <mrpt/utils/CImage.h>
#include <mrpt/utils/safe_pointers.h>

/*---------------------------------------------------------------
        Class
  ---------------------------------------------------------------*/
namespace mrpt
{
namespace hwdrivers
{
/** 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 <a
 * href="http://www.mrpt.org/Building_and_Installing_Instructions" > MRPT's
 * wiki</a>. In Win32, a precompiled version for Visual Studio must be also
 * downloaded as explained in <a
 * href="http://www.mrpt.org/Building_and_Installing_Instructions" >the
 * wiki</a>.
  * \ingroup mrpt_hwdrivers_grp
  */
class CFFMPEG_InputStream
{
   private:
        /** The internal ffmpeg state */
        mrpt::utils::void_ptr_noncopy m_state;
        /** The open URL */
        std::string m_url;
        bool m_grab_as_grayscale;

   public:
        /** Default constructor, does not open any video source at startup */
        CFFMPEG_InputStream();
        /** Destructor */
        virtual ~CFFMPEG_InputStream();

        /** 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.
          *
          * \sa close, retrieveFrame
          * \return false on any error (and error info dumped to cerr), true on
         * success.
          */
        bool openURL(
                const std::string& url, bool grab_as_grayscale = false,
                bool verbose = false);

        /** Return whether the video source was open correctly */
        bool isOpen() const;

        /** Close the video stream (this is called automatically at destruction).
          * \sa openURL
          */
        void close();

        /** Get the frame-per-second (FPS) of the video source, or "-1" if the video
         * is not open. */
        double getVideoFPS() const;

        /** 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.
          *  \return false on any error, true on success.
          *  \sa openURL, close, isOpen
          */
        bool retrieveFrame(mrpt::utils::CImage& out_img);
};
}
}

#endif