// Copyright (C) 2001,2002,2004 Federico Montesino Pouzols <fedemp@altern.org>. // // This program 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. // // This program 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. // // As a special exception, you may use this file as part of a free software // library without restriction. Specifically, if other files instantiate // templates or use macros or inline functions from this file, or you compile // this file and link it with other files to produce an executable, this // file does not by itself cause the resulting executable to be covered by // the GNU General Public License. This exception does not however // invalidate any other reasons why the executable file might be covered by // the GNU General Public License. // // This exception applies only to the code released under the name GNU // ccRTP. If you copy code from other releases into a copy of GNU // ccRTP, as the General Public License permits, the exception does // not apply to the code that you add in this way. To avoid misleading // anyone as to the status of such modified files, you must delete // this exception notice from them. // // If you write modifications of your own for GNU ccRTP, it is your choice // whether to permit this exception to apply to your modifications. // If you do not wish that, delete this exception notice. // /** * @file ioqueue.h * * @short Generic RTP input/output queues. **/ #ifndef CCXX_RTP_IOQUEUE_H_ #define CCXX_RTP_IOQUEUE_H_ #include <ccrtp/iqueue.h> #include <ccrtp/oqueue.h> #ifdef CCXX_NAMESPACES namespace ost { #endif /** * @defgroup ioqueue Generic RTP input/output queues. * @{ **/ /** * @class RTPDataQueue * * A packet queue handler for building different kinds of RTP protocol * systems. The queue manages both incoming and outgoing RTP packets, * as well as synchronization and transmission/reception timers. By * making the queue handler a seperate base class it becomes possible * to define RTP classes for RTP profiles and sessions of different * types. * * Outgoing packets are sent via the OutgoingDataQueue::putData method. * * Incoming packets can be retrieved via IncomingDataQueue::getData * method. * * @author David Sugar <dyfet@ostel.com> * @short RTP data queue handler. */ class __EXPORT RTPDataQueue : public IncomingDataQueue, public OutgoingDataQueue { public: /** * @enum Tos rtp.h cc++/rtp.h * @short Type of network service the application uses. * * If the application uses enhanced network service, for * instance Integrated Services or Differentiated Services, it * <em>has not</em> to ensure fair competition with TCP, * provided that the requested service is actually being * delivered. Whenever the application uses best-effort * service or the requested enhanced service is not actually * being delivered, it <em>has</em> to ensure fair competition * with TCP. By default, best-effot is assumed. * * @note Although not required, RTP packets are always sent on * top of UDP segments. No other underlying transport protocol * is supported at present. * * @todo implement fair competition with tcp **/ typedef enum { tosBestEffort, ///< Best-effort network service tosEnhanced ///< Enhanced network service } Tos; /** * Specify the kind of service the application expects to use. * * @param tos type of service the application expects to use * * @note If enhanced service is specified but packet loss is * high (the requested service does not appear to actually be * delivered) ccRTP defaults to best-effort suitable * behaviour: guarantee fair competition with TCP. * * @todo Implement fair competition with tcp **/ inline void setTypeOfService(Tos tos) { typeOfService = tos; } /** * Enable packet queue processing in the stack. This method * will not any thread of execution. **/ inline void enableStack() { dataServiceActive = true; } /** * Disable packet queue processing in the stack. **/ inline void disableStack() { dataServiceActive = false; } /** * Get active connection state flag. * * @return true if connection "active". */ inline bool isActive() const { return dataServiceActive; } /** * Get the timestamp that should be given for a packet whose * payload sampling instant corresponds to the current system * time. * * The timestamp applications should provide for each packet * represents the sampling instant of its payload and should * not be a reading of the system clock. Nevertheless, the * internal operation of the RTP stack relies on the accuracy * of the provided timestamp, since several computations * assume that there is a certain degree of correspondence * between the timestamp and the system clock. * * It is recommended that applications use this method in * order to <em>periodically adjust the RTP timestamp</em>. * * In particular, it is advisable getting the timestamp * corresponding to the first sampling instant or any instant * after a period of inactivity through a call to this method. * * Applications should use the nominal sampling or * any other value provided by the coder in order to compute * the next timestamps with minimum computational requirement. * * For instance, an application using an RTP profile that * specifies a fixed sampling rate of 8 Khz with eight bits * per sample, continuously transmitting audio blocks 80 * octets long, would transmit 100 packets every * second. Every packet would carry a timestamp 80 units * greater than the previous one. So, the first timestamp * would be obtained from this method, whereas the following * ones would be computed adding 80 every time. Also the * timestamp should be increased for every block whether * it is put in the queue or dropped. * * The aforementioned increment can be obtained from the * RTPDataQueue::getTimestampIncrement() method rather than * computing it by hand in the application. * * @note Frame based applications must follow a specific * timestamping method, probably specified in a profile. * * @note You should take into account that by default ccRTP * assumes that the application begins sampling at the queue * creation time. Moreover, the first sampling instant is * assigned a "user visible" timestamp of 0, although the RTP * stack will then add internally a ramdom offset unknown to * the application. That is to say, the application may count * samples from 0 in order to get the timestamp for the next * packet, provided that the first sampling instant is the * same as the queue creation time. Nevertheless, this * simpler way of starting will not be as accurate as it would * be if the application got at least the first timestamp * through getCurrentTimestamp. <em>We provide this option * since ccRTP interface is evolving, but we admit that it is * ugly, we could remove this option or even replace uint32 * timestamps with a restrictively regulated object; * suggestions are gladly welcomed</em> **/ uint32 getCurrentTimestamp() const; /** * Specify the bandwidth of the current session. * * @param bw bandwidth of the current session, in bits/s. * * @see AVPQueue::setControlBandwidth() */ void setSessionBandwidth(uint32 bw) { sessionBw = bw; } uint32 getDefaultSessionBandwidth() const { return defaultSessionBw; } uint32 getSessionBandwidth() const { return sessionBw; } /** * Set the packet timeclock for synchronizing timestamps. **/ inline void setTimeclock() { timeclock.setTimer(); } /** * Get the packet timeclock for synchronizing timestamps. * * @return runtime in milliseconds since last set. */ inline timeout_t getTimeclock() const { return timeclock.getElapsed(); } protected: /** * Constructor. This will generate a random application SSRC * identifier. * * @param size an estimation of the number of participants in * the session **/ RTPDataQueue(uint32 size = defaultMembersHashSize); /** * Using this constructor you can start a session with the * given ssrc, instead of the usual randomly generated * one. This is necessary when you need to initiate several * sessions having the same SSRC identifier, for instance, to * implement layered encoding, in which case each layer is * managed through a different session but all sessions share * the same SSRC identifier. * * @warning This doesn't seem to be a good solution * * @param ssrc Synchronization SouRCe identifier for this session * @param size an estimation of the number of participants in the * session */ RTPDataQueue(uint32* ssrc, uint32 size = defaultMembersHashSize); /** * The queue destructor flushes the queue and stops all * services. */ inline virtual ~RTPDataQueue() { endQueue(); } /** * A plugin point for timer tick driven events. */ inline virtual void timerTick() { return; } void renewLocalSSRC() {IncomingDataQueue::renewLocalSSRC();} private: RTPDataQueue(const RTPDataQueue &o); RTPDataQueue& operator=(const RTPDataQueue &o); /** * Global queue initialization. * * @param localSSRC local 32-bit SSRC identifier **/ void initQueue(); protected: /** * This method ends the queue. */ void endQueue(); /** * This function is used to check for and schedule against * arriving packets based on the derived connection type. * * @return true if packet waiting for processing. * @param number of microseconds to wait. */ virtual bool isPendingData(microtimeout_t timeout) = 0; private: // true if connection "active" volatile bool dataServiceActive; Tos typeOfService; TimerPort timeclock; /* RTP session bandwidth control */ static const uint32 defaultSessionBw; uint32 sessionBw; }; /** @}*/ // ioqueue #ifdef CCXX_NAMESPACES } #endif #endif //CCXX_RTP_IOQUEUE_H_ /** EMACS ** * Local variables: * mode: c++ * c-basic-offset: 8 * End: */