總述

Live555是使用c++編寫的RTSP開源庫(kù)，以文件為載體進(jìn)行推流，其中實(shí)現(xiàn)了多種類型的音頻以及視頻的流化。

簡(jiǎn)述RTSP

RTSP是一種媒體傳輸協(xié)議，基于TCP協(xié)議，主要功能為媒體播放的控制以及開始連接時(shí)的握手操作。時(shí)間流傳輸走的時(shí)RTP協(xié)議，流傳輸控制協(xié)議走的是RTCP，RTP和RTCP具體使用TCP還是UDP，有RTSP SETUP階段根據(jù)客戶端選擇而定。

實(shí)現(xiàn)自定義數(shù)據(jù)流傳輸

首先實(shí)現(xiàn)一個(gè)比較通用的MediaSubsession，繼承OnDemandServerMediaSubsession

class ComMediaSubsession:public OnDemandServerMediaSubsession 
{
	public:
		static ComMediaSubsession* createNew(UsageEnvironment& env, int streamType, int videoType, int channelNO, 
				bool reuseFirstSource, portNumBits initalNumPort = 6970);
	protected:
		ComMediaSubsession(UsageEnvironment& env, int streamType, int videoType, int channelNO, 
				bool reuseFirstSource, portNumBits initalNumPort);
		~ComMediaSubsession();
		
	protected:
		// virtual function  new source and rtplink
		FramedSource* createNewStreamSource(unsigned clientsessionId, unsigned& estBitrate);
		RTPSink* createNewRTPSink(Groupsock* rtpGroupsock, unsigned char rtpPayloadTypeIfDynamic, FramedSource* inputSource);
	
	public:
		int fStreamType;
		int fVideoType;
		int fChannelNO;
		
};

#include "ComMediaSubsession.h"
#include "ComFrameSource.h"
#include "H264VideoStreamFramer.hh"
#include "H264VideoRTPSink.hh"
#include "MP3ADURTPSink.hh"
#include "MPEG1or2AudioRTPSink.hh"


ComMediaSubsession::ComMediaSubsession(UsageEnvironment& env, int streamType, int videoType, int channelNO, bool reuseFirstSource, portNumBits initalNumPort)
	:OnDemandServerMediaSubsession(env, reuseFirstSource), fStreamType(streamType), fVideoType(videoType), fChannelNO(channelNO)
{
}

ComMediaSubsession::~ComMediaSubsession()
{

}


ComMediaSubsession* DemoH264MediaSubsession::createNew(UsageEnvironment& env, int streamType, int videoType, int channelNO, 
		bool reuseFirstSource, portNumBits initalNumPort)
{
	ComMediaSubsession* sms = new ComMediaSubsession(env, streamType, videoType, channelNO, reuseFirstSource, initalNumPort);
	return sms;
}


FramedSource* ComMediaSubsession::createNewStreamSource(unsigned clientsessionId, unsigned& estBitrate)
{
	if(fVideoType == 0x01)
	{ 
	    // H264 video 
		estBitrate = 2000; // kbps 
		ComFrameSource * source = ComFrameSource::createNew(envir(), fStreamType, fChannelNO, 0);
		if ( source == NULL )
		{
			DBG_LIVE555_PRINT("create source failed videoType:%d!\n", fVideoType );
			return NULL;
		}
		return H264VideoStreamFramer::createNew(envir(), source);
	}
	else if ( fVideoType == 0x2) 
	{   
	    // Mpeg-4 video  
	    estBitrate = 128; // kbps 
		ComFrameSource * source = ComFrameSource::createNew(envir(), fStreamType, fChannelNO, 1);
		if ( source == NULL )
		{
			DBG_LIVE555_PRINT("create source failed videoType:%d!\n", fVideoType );
			return NULL;
		}
		return source;
	}
	return NULL;	
}


RTPSink* ComMediaSubsession::createNewRTPSink(Groupsock* rtpGroupsock, unsigned char rtpPayloadTypeIfDynamic, FramedSource* inputSource)
{
	if( fVideoType == 0x01)
	{
	    // H264 video
		return H264VideoRTPSink::createNew(envir(), rtpGroupsock, rtpPayloadTypeIfDynamic);
		
	}
	else if( fVideoType == 0x02)
	{ 
	    //  Mpeg-4
		return MP3ADURTPSink::createNew(envir(), rtpGroupsock,rtpPayloadTypeIfDynamic);
	}
    return NULL;
}

接著實(shí)現(xiàn)數(shù)據(jù)獲取類文章來源地址http://www.zghlxwxcb.cn/news/detail-523330.html

#include "FramedSource.hh"

class ComFrameSource:public FramedSource 
{
	public:
		static ComFrameSource* createNew(UsageEnvironment& env, int streamtype, int channelno, int sourceType); 
	protected:
		ComFrameSource(UsageEnvironment& env, long sourceHandle, int sourceType);
		~ComFrameSource();
	private:
		virtual void doGetNextFrame();
	public:
		void doStopGetFrame();
	public:
		unsigned fLastBufSize;
		unsigned fLeftDataSize;
		int fSourceType;
		int fFirstFrame;
		
};

#include "ComFrameSource.h"

ComFrameSource::ComFrameSource(UsageEnvironment& env,  int sourceType):
	FramedSource(env), fLastBufSize(0), fLeftDataSize(0), fSourceType(sourceType), fFirstFrame(1)
{
 
}


ComFrameSource::~ComFrameSource()
{ 

}


ComFrameSource* ComFrameSource::createNew(UsageEnvironment& env, int streamType, int channelNO, int sourceType)
{
	
	return new ComFrameSource(env, sourceType);
	
}



void ComFrameSource::doGetNextFrame()
{
	int ret = 0;

    /*實(shí)現(xiàn)獲取數(shù)據(jù)到fTo，最大fMaxSize*/
	ret = getStreamData(fSourceHandle, (char *)fTo, fMaxSize);
	if (ret <= 0)
	{
	    fFrameSize = 0;
		nextTask() = envir().taskScheduler().scheduleDelayedTask(10,
				  (TaskFunc*)FramedSource::afterGetting, this);
		return;
	}

	gettimeofday(&fPresentationTime, NULL);
	
	
	// Switch to another task, and inform the reader that he has data:
	nextTask() = envir().taskScheduler().scheduleDelayedTask(10,
				  (TaskFunc*)FramedSource::afterGetting, this);



}

void ComFrameSource::doStopGetFrame()
{

}

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