sems/core/AmDtmfDetector.h

/*
 * $Id$
 *
 * Copyright (C) 2005 Andriy I Pylypenko
 *
 * This file is part of sems, a free SIP media server.
 *
 * sems 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 2 of the License, or
 * (at your option) any later version
 *
 * For a license to use the ser software under conditions
 * other than those described here, or to purchase support for this
 * software, please contact iptel.org by e-mail at the following addresses:
 *    info@iptel.org
 *
 * sems 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 this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#ifndef _AmDtmfDetector_h_
#define _AmDtmfDetector_h_

#include "AmEventQueue.h"
#include "rtp/telephone_event.h"

#include <string>
using namespace std;

//
// Forward declarations
//
class AmSession;
class AmDtmfDetector;
class AmDtmfEventHandler;
class AmRequest;

namespace Dtmf
{
    enum EventSource { SOURCE_RTP, SOURCE_SIP, SOURCE_INBAND, SOURCE_DETECTOR };
};
/**
 * \brief sink for audio to be processed by the inband DTMF detector 
 * 
 * This class adds processing of timeouts for DTMF detection
 */
class AmDtmfEventQueue : public AmEventQueue
{
private:
    AmDtmfDetector *m_detector;

public:
    AmDtmfEventQueue(AmDtmfDetector *);
    /**
     * Reimplemented abstract method from AmEventQueue
     */
    void processEvents();
    void putDtmfAudio(const unsigned char *, int size, int user_ts);
};

/**
 * \brief Base class for DTMF events
 */
class AmDtmfEvent : public AmEvent
{
protected:
    /**
     * Code of the key
     */
    int m_event;
    /**
     * Duration of keypress in miliseconds
     */
    int m_duration_msec;

    /**
     * Constructor
     */
    AmDtmfEvent(int id)
        : AmEvent(id)
    {
    }

public:
    AmDtmfEvent(int event, int duration)
        : AmEvent(Dtmf::SOURCE_DETECTOR), m_event(event), m_duration_msec(duration)
    {
    }
    /**
     * Code of the key
     */
    int event() const { return m_event; }
    /**
     * Duration of keypress in miliseconds
     */
    int duration() const { return m_duration_msec; }
};

/**
 * \brief DTMF received via RTP
 */
class AmRtpDtmfEvent : public AmDtmfEvent
{
private:
    /**
     * E flag from RTP packet
     */
    int m_e;
    /**
     * Volume value from RTP packet
     */
    int m_volume;

public:
    /**
     * Constructor
     * @param payload data from rtp packet of payload type telephone-event
     * @param sample_rate sampling rate (from SDP payload description)
     */
    AmRtpDtmfEvent(const dtmf_payload_t *payload, int sample_rate);

    /**
     * Volume value from RTP packet
     */
    int volume() { return m_volume; }
    /**
     * E flag from RTP packet
     */
    int e() { return m_e; }
};

/**
 * \brief DTMF received via SIP INFO request
 */
class AmSipDtmfEvent : public AmDtmfEvent
{
private:
    /**
     * Parser for application/dtmf-relay
     */
    void parseRequestBody(const string&);
    /**
     * Parser for application/dtmf-relay
     */
    void parseLine(const string&);

public:
    /**
     * Constructor
     */
    AmSipDtmfEvent(const string& request_body);
};

/**
 * \brief Inband DTMF detector
 *
 * This class implements detection of DTMF from audio stream
 */
class AmInbandDtmfDetector
{
private:
    /**
     * Owner of this class instance
     */
    AmDtmfDetector *m_owner;
    /**
     * Time when first audio packet containing current DTMF tone was detected
     */
    struct timeval m_startTime;

    static const int DTMF_NPOINTS = 205;        /* Number of samples for DTMF recognition */
    static const int REL_DTMF_NPOINTS = 205;    /* Number of samples for DTMF recognition */
    static const int SAMPLERATE = 8000;
    /**
     * DTMF recognition successfull only if no less than DTMF_INTERVAL
     * audio packets were processed and all gave the same result
     */
    static const int DTMF_INTERVAL = 3;

    int m_buf[DTMF_NPOINTS];
    char m_last;
    int m_idx;
    int m_result[16];
    int m_lastCode;

    int m_count;

    void isdn_audio_goertzel_relative();
    void isdn_audio_eval_dtmf_relative();
    void isdn_audio_calc_dtmf(const signed short* buf, int len);

public:
    AmInbandDtmfDetector(AmDtmfDetector *owner);
    /**
     * Entry point for audio stream
     */
    int streamPut(const unsigned char* samples, unsigned int size, unsigned int user_ts);
};


/**
 * \brief SIP INFO DTMF detector
 *
 * This class implements detection of DTMF from audio stream
 */
class AmSipDtmfDetector
{
private:
    AmDtmfDetector *m_owner;

public:
    AmSipDtmfDetector(AmDtmfDetector *owner);
    void process(AmSipDtmfEvent *event);
};

/**
 * \brief RTP DTMF detector
 *
 * This class implements detection of DTMF sent via RTP
 */
class AmRtpDtmfDetector
{
private:
    /**
     * Owner of this class instance
     */
    AmDtmfDetector *m_owner;
    /**
     * Is there event pending?
     */
    bool m_eventPending;
    int m_currentEvent;
    int m_packetCount;

    static const int MAX_PACKET_WAIT = 3;
    /**
     * Time when first packet for current event was received
     */
    struct timeval m_startTime;

    /**
     * Send out pending event
     */
    void sendPending();

public:
    /**
     * Constructor
     * @param owner is the owner of this class instance
     */
    AmRtpDtmfDetector(AmDtmfDetector *owner);
    /**
     * Process RTP DTMF event
     */
    void process(AmRtpDtmfEvent *event);
    void checkTimeout();
};

/**
 * \brief DTMF detector class
 *
 * This class collects DTMF info from three sources: RTP (RFC 2833), 
 * SIP INFO method (RFC 2976) and DTMF tones from audio stream.
 * Received DTMF events are further reported to SEMS application via 
 * DialogState::onDtmf() call.
 */
class AmDtmfDetector : public AmEventHandler
{
private:
    static const int WAIT_TIMEOUT = 100; // miliseconds
    /**
     * Session this class belongs to.
     */
    AmSession *m_session;
    AmRtpDtmfDetector m_rtpDetector;
    AmSipDtmfDetector m_sipDetector;
    AmInbandDtmfDetector m_inbandDetector;

    struct timeval m_startTime;
    struct timeval m_lastReportTime;
    int m_currentEvent;
    bool m_eventPending;

    bool m_sipEventReceived;
    bool m_inbandEventReceived;
    bool m_rtpEventReceived;

    AmMutex m_reportLock;

    /**
     * Implementation of AmEventHandler::process(). 
     * Processes events from AmMediaProcessor.
     * @see AmEventHandler
     */
    virtual void process(AmEvent *);

    void reportEvent();

public:
    /**
     * Constructor
     * @param session is the owner of this class instance
     */
    AmDtmfDetector(AmSession *session);
    virtual ~AmDtmfDetector() {}

    /**
     * Through this method the AmDtmfDetector receives events that was
     * detected by specific detectors.
     * @param event code of key pressed
     * @param source which detector posted this event
     * @param start time when key was pressed
     * @param stop time when key was released
     */
    void registerKeyReleased(int event, Dtmf::EventSource source,
                             const struct timeval& start, const struct timeval& stop);
    /**
     * Through this method the AmDtmfDetector receives events that was
     * detected by specific detectors.
     * @param event code of key released
     * @param source which detector posted this event
     */
    void registerKeyPressed(int event, Dtmf::EventSource source);

    void checkTimeout();
    void putDtmfAudio(const unsigned char *, int size, int user_ts);
};
#endif // _AmDtmfDetector_h_