文如其名，最近在做的项目要求利用RTSP协议转发处理完的H264视频数据给上一层客户端，环境是Windows的VS2013，于是就各种百度谷歌找代码。结果在得到利用live555去做比较简单的结论的同时也悲情地发现，网上别人贴出来的代码基本都是Linux上面的。在修改了两份来适用于Windows无效后，又一次陷入了百度谷歌的无尽搜索中。Anyway，最后终于解决了，所以贴出代码跟大家分享下，希望能给和我需求相似的童鞋一点启发，也希望有高手指正其中的问题。

用live555进行RTSP的播放基本上是通过修改其给出来的播放本地文件的DEMO来实现的。但由于其DEMO封装的比较深，所以要直接修改他的fread处的代码变成内存拷贝来实现实时传输会显得比较别扭。本文参考了网上的一些代码，自定义了一个继承自H264VideoFileServerMediaSubsession的类来来进行处理，同时定义了一个继承自FramedSource的类来做内存的拷贝操作，该类亦是区别于读本地文件和实时流之紧要处。

一口气杂七杂八说了好多，下面贴出代码吧。如果觉得需要或者懒得自己搭建live555的环境亦可以在文中最后的链接中下载该工程（环境为VS2013），如果你的VS版本合适即可直接运行。

主文件（程序入口）

#include "H264LiveVideoServerMediaSubssion.hh"
#include "H264FramedLiveSource.hh"
#include "liveMedia.hh"
#include "BasicUsageEnvironment.hh"

#define BUFSIZE 1024*200

static void announceStream(RTSPServer* rtspServer, ServerMediaSession* sms,char const* streamName)//显示RTSP连接信息
{
	char* url = rtspServer->rtspURL(sms);
	UsageEnvironment& env = rtspServer->envir();
	env <<streamName<< "\n";
	env << "Play this stream using the URL \"" << url << "\"\n";
	delete[] url;
}

int main(int argc, char** argv) 
{
	//设置环境
	UsageEnvironment* env;
	Boolean reuseFirstSource = False;//如果为“true”则其他接入的客户端跟第一个客户端看到一样的视频流，否则其他客户端接入的时候将重新播放
	TaskScheduler* scheduler = BasicTaskScheduler::createNew();
	env = BasicUsageEnvironment::createNew(*scheduler);

	//创建RTSP服务器
	UserAuthenticationDatabase* authDB = NULL;
	RTSPServer* rtspServer = RTSPServer::createNew(*env, 8554, authDB);
	if (rtspServer == NULL) {
		*env << "Failed to create RTSP server: " << env->getResultMsg() << "\n";
		exit(1);
	}
	char const* descriptionString= "Session streamed by \"testOnDemandRTSPServer\"";

	//模拟实时流发送相关变量
	int datasize;//数据区长度
	unsigned char*  databuf;//数据区指针
	databuf = (unsigned char*)malloc(1024*1024);
	bool dosent;//rtsp发送标志位，为true则发送，否则退出

	//从文件中拷贝1M数据到内存中作为实时网络传输内存模拟，如果实时网络传输应该是双线程结构，记得在这里加上线程锁
	//此外实时传输的数据拷贝应该是发生在H264FramedLiveSource文件中，所以这里只是自上往下的传指针过去给它
	FILE *pf;
	fopen_s(&pf, "test.264", "rb");
	fread(databuf, 1, BUFSIZE, pf);
	datasize = BUFSIZE;
	dosent = true;
	fclose(pf);

	//上面的部分除了模拟网络传输的部分外其他的基本跟live555提供的demo一样，而下面则修改为网络传输的形式，为此重写addSubsession的第一个参数相关文件
	char const* streamName = "h264ESVideoTest";
	ServerMediaSession* sms = ServerMediaSession::createNew(*env, streamName, streamName,descriptionString);
	sms->addSubsession(H264LiveVideoServerMediaSubssion::createNew(*env, reuseFirstSource, &datasize, databuf,&dosent));//修改为自己实现的H264LiveVideoServerMediaSubssion
	rtspServer->addServerMediaSession(sms);

	announceStream(rtspServer, sms, streamName);//提示用户输入连接信息
	env->taskScheduler().doEventLoop(); //循环等待连接

	free(databuf);//释放掉内存
	return 0;
}

H264VideoFileServerMediaSubsession.hh

#ifndef _H264_LIVE_VIDEO_SERVER_MEDIA_SUBSESSION_HH
#define _H264_LIVE_VIDEO_SERVER_MEDIA_SUBSESSION_HH
#include "H264VideoFileServerMediaSubsession.hh"

class H264LiveVideoServerMediaSubssion : public H264VideoFileServerMediaSubsession {

public:
	static H264LiveVideoServerMediaSubssion* createNew(UsageEnvironment& env, Boolean reuseFirstSource, int *datasize, unsigned char*  databuf, bool *dosent);

protected: // we're a virtual base class
	H264LiveVideoServerMediaSubssion(UsageEnvironment& env, Boolean reuseFirstSource, int *datasize, unsigned char*  databuf, bool *dosent);
	~H264LiveVideoServerMediaSubssion();

protected: // redefined virtual functions
	FramedSource* createNewStreamSource(unsigned clientSessionId,unsigned& estBitrate);
public:
	char fFileName[100];

	int *Server_datasize;//数据区大小指针
	unsigned char*  Server_databuf;//数据区指针
	bool *Server_dosent;//发送标示
};
#endif

#include "H264LiveVideoServerMediaSubssion.hh"
#include "H264FramedLiveSource.hh"
#include "H264VideoStreamFramer.hh"

H264LiveVideoServerMediaSubssion* H264LiveVideoServerMediaSubssion::createNew(UsageEnvironment& env, Boolean reuseFirstSource, int *datasize, unsigned char*  databuf, bool *dosent)
{
	return new H264LiveVideoServerMediaSubssion(env, reuseFirstSource, datasize, databuf, dosent);
}

H264LiveVideoServerMediaSubssion::H264LiveVideoServerMediaSubssion(UsageEnvironment& env, Boolean reuseFirstSource, int *datasize, unsigned char*  databuf, bool *dosent)
: H264VideoFileServerMediaSubsession(env, fFileName, reuseFirstSource)//H264VideoFileServerMediaSubsession不是我们需要修改的文件，
																	  //但是我们又要用它来初始化我们的函数，
																	  //所以给个空数组进去即可
{
	Server_datasize = datasize;//数据区大小指针
	Server_databuf = databuf;//数据区指针
	Server_dosent = dosent;//发送标示
}

H264LiveVideoServerMediaSubssion::~H264LiveVideoServerMediaSubssion()
{
}

FramedSource* H264LiveVideoServerMediaSubssion::createNewStreamSource(unsigned clientSessionId, unsigned& estBitrate)
{
	/* Remain to do : assign estBitrate */
	estBitrate = 1000; // kbps, estimate

	//创建视频源
	H264FramedLiveSource* liveSource = H264FramedLiveSource::createNew(envir(), Server_datasize, Server_databuf, Server_dosent);
	if (liveSource == NULL)
	{
		return NULL;
	}

	// Create a framer for the Video Elementary Stream:
	return H264VideoStreamFramer::createNew(envir(), liveSource);
}

H264FramedLiveSource.hh

#ifndef _H264FRAMEDLIVESOURCE_HH
#define _H264FRAMEDLIVESOURCE_HH

#include <FramedSource.hh>


class H264FramedLiveSource : public FramedSource
{
public:
	static H264FramedLiveSource* createNew(UsageEnvironment& env, int *datasize, unsigned char*  databuf, bool *dosent, unsigned preferredFrameSize = 0, unsigned playTimePerFrame = 0);

protected:
	H264FramedLiveSource(UsageEnvironment& env, int *datasize, unsigned char*  databuf, bool *dosent, unsigned preferredFrameSize, unsigned playTimePerFrame);
	~H264FramedLiveSource();

private:
	virtual void doGetNextFrame();
	int TransportData(unsigned char* to, unsigned maxSize);

protected:
	int *Framed_datasize;//数据区大小指针
	unsigned char *Framed_databuf;//数据区指针
	bool *Framed_dosent;//发送标示

	int readbufsize;//记录已读取数据区大小
	int bufsizel;//记录数据区大小
};

#endif

#include "H264FramedLiveSource.hh"

H264FramedLiveSource::H264FramedLiveSource(UsageEnvironment& env, int *datasize, unsigned char*  databuf, bool *dosent, unsigned preferredFrameSize, unsigned playTimePerFrame)
: FramedSource(env)
{
	Framed_datasize = datasize;//数据区大小指针
	Framed_databuf = databuf;//数据区指针
	Framed_dosent = dosent;//发送标示
}

H264FramedLiveSource* H264FramedLiveSource::createNew(UsageEnvironment& env, int *datasize, unsigned char*  databuf, bool *dosent, unsigned preferredFrameSize, unsigned playTimePerFrame)
{
	H264FramedLiveSource* newSource = new H264FramedLiveSource(env, datasize, databuf, dosent, preferredFrameSize, playTimePerFrame);
	return newSource;
}

H264FramedLiveSource::~H264FramedLiveSource()
{
}

void H264FramedLiveSource::doGetNextFrame()
{
	if (*Framed_dosent == true)
	{
		*Framed_dosent = false;
		bufsizel = *Framed_datasize;
		readbufsize = 0;

		fFrameSize = fMaxSize;
		memcpy(fTo, Framed_databuf + readbufsize, fFrameSize);
		readbufsize += fFrameSize;
	}
	else
	{
		if (bufsizel - readbufsize>fMaxSize)
		{
			fFrameSize = fMaxSize;
			memcpy(fTo, Framed_databuf + readbufsize, fFrameSize);
			readbufsize += fFrameSize;
		}
		else
		{
			memcpy(fTo, Framed_databuf + readbufsize, bufsizel - readbufsize);
			*Framed_dosent = true;
		}
	}

	nextTask() = envir().taskScheduler().scheduleDelayedTask(0,(TaskFunc*)FramedSource::afterGetting, this);//表示延迟0秒后再执行 afterGetting 函数
	return;
}

Windows下利用live555实现H264实时流RTSP发送