root/extra_lib/include/avcap/linux/V4L2_VidCapManager.h

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/*
 * (c) 2005, 2008 Nico Pranke <Nico.Pranke@googlemail.com>, Robin Luedtke <RobinLu@gmx.de> 
 *
 * This file is part of avcap.
 *
 * avcap is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * avcap is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with avcap.  If not, see <http://www.gnu.org/licenses/>.
 */

/* avcap is free for non-commercial use.
 * To use it in commercial endeavors, please contact Nico Pranke <Nico.Pranke@googlemail.com>.
 */


#ifndef V4L2_VIDCAPMANAGER_H_
#define V4L2_VIDCAPMANAGER_H_

#include <sys/types.h>
#include <list>
#include <time.h>

#include "CaptureManager.h"

namespace avcap
{
        class V4L2_DeviceDescriptor;
        class FormatManager;
        class IOBuffer;
        class CaptureHandler;

        //! The Video4Linux2-API video capture manager.
        
        /*! This class can be used to capture video data from a V4L2 video device. 
         * The manager creates a defined number 
         * of IOBuffers and permanently reuses them to store the captured data. 
         * Since the number of these buffers is finite, it is important that applications 
         * call IOBuffer::release() as soon as they don't need the data anymore. The
         * access to the internal buffer-list is synchronized, so \c release() can be called
         * from any thread at any time.
         * Typical applications don't create objects of this class directly. They obtain
         * an instance from CaptureDevice. */
         
        class V4L2_VidCapManager: public CaptureManager
        {
        public:
                enum
                {
                        MAX_BUFFERS = 32,       //!< The maximum number of IOBuffers.
                        DEFAULT_BUFFERS = 16    //!< The default number of used IOBuffers.
                };
                
                enum IOMethod
                {
                        IO_METHOD_NOCAP = 0,
                IO_METHOD_READ,
                IO_METHOD_MMAP,
                IO_METHOD_USERPTR,
                };

        private:
                typedef std::list<IOBuffer*> IOBufList;
                
                V4L2_DeviceDescriptor   *mDeviceDescriptor;
                FormatManager           *mFormatMgr;

                IOBufList                       mBuffers;
                int                                     mNumBufs;
                int                                     mMethod;
                int                                     mState;
                pthread_t*                      mThread;
                int                             mFinish;
                pthread_mutex_t         mLock;
                timeval                         mStartTime;

                int                             mSequence;
                int                                     mDTNumerator;
                int                                     mDTDenominator;
                int                                     mAvailableBuffers;
        
        public:
                V4L2_VidCapManager(V4L2_DeviceDescriptor* dd, FormatManager* fmt_mgr, int nbufs = DEFAULT_BUFFERS);
                
                virtual ~V4L2_VidCapManager();
                
                int init();
                
                int destroy();
                
                int startCapture();

                int stopCapture();
                
                int getNumIOBuffers();

        private:
                int start_read();
                int start_mmap();
                int start_userptr();

                int stop_read();
                int stop_mmap();
                int stop_userptr();

                IOBuffer* dequeue();
                int enqueue(IOBuffer* buf);
                
                IOBuffer* findBuffer(int index);
                static void run(void* mgr);
                
                void clearBuffers();
                int getUsedBufferCount();
        };
}

#endif // V4L2_VIDCAPMANAGER_H_

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