linux下基于libRTMP的接收流媒体的程序

看了雷博的一篇关于rtmp的文章，学习记录以作备忘。

使用librtmp接收RTMP流的函数执行流程图如下图：

流程图中关键函数的作用如下所列：
InitSockets()：初始化Socket
RTMP_Alloc()：为结构体“RTMP”分配内存。
RTMP_Init()：初始化结构体“RTMP”中的成员变量。
RTMP_SetupURL()：设置输入的RTMP连接的URL。
RTMP_Connect()：建立RTMP连接，创建一个RTMP协议规范中的NetConnection。
RTMP_ConnectStream()：创建一个RTMP协议规范中的NetStream。
RTMP_Read()：从服务器读取数据。
RTMP_Close()：关闭RTMP连接。
RTMP_Free()：释放结构体“RTMP”。
CleanupSockets()：关闭Socket。

其中NetStream和NetConnection是RTMP协议规范中的两个逻辑结构。NetStream建立在NetConnection之上。一个NetConnection可以包含多个NetStream。它们之间的关系如下图所示：

源代码rtmp2flv.c：

#include 
#include 
#include "librtmp/rtmp_sys.h"
#include "librtmp/log.h"
#include "librtmp/rtmp.h"

int InitSockets()
{
#if 0
	WORD version;
	WSADATA wsaData;
	version = MAKEWORD(1, 1);
	return (WSAStartup(version, &wsaData) == 0);
#endif
}

void CleanupSockets()
{
#if 0
	WSACleanup();
#endif
}

int main(int argc, char* argv[])
{
	InitSockets();
	
	double duration=-1;
	int nRead;
	//is live stream ?
	char bLiveStream=1;				
	
	
	int bufsize=1024*1024*10;			
	char *buf=(char*)malloc(bufsize);
	memset(buf,0,bufsize);
	long countbufsize=0;
	
	FILE *fp=fopen("receive.flv","wb");
	if (!fp){
		RTMP_LogPrintf("Open File Error.\n");
		CleanupSockets();
		return -1;
	}
	
	/* set log level */
	//RTMP_LogLevel loglvl=RTMP_LOGDEBUG;
	//RTMP_LogSetLevel(loglvl);

	RTMP *rtmp=RTMP_Alloc();
	RTMP_Init(rtmp);
	//set connection timeout,default 30s
	rtmp->Link.timeout=10;	
	// HKS's live URL
	if(!RTMP_SetupURL(rtmp,"rtmp://live.hkstv.hk.lxdns.com/live/hks"))
	{
		RTMP_Log(RTMP_LOGERROR,"SetupURL Err\n");
		RTMP_Free(rtmp);
		CleanupSockets();
		return -1;
	}
	if (bLiveStream){
		rtmp->Link.lFlags|=RTMP_LF_LIVE;
	}
	
	//1hour
	RTMP_SetBufferMS(rtmp, 3600*1000);		
	
	if(!RTMP_Connect(rtmp,NULL)){
		RTMP_Log(RTMP_LOGERROR,"Connect Err\n");
		RTMP_Free(rtmp);
		CleanupSockets();
		return -1;
	}

	if(!RTMP_ConnectStream(rtmp,0)){
		RTMP_Log(RTMP_LOGERROR,"ConnectStream Err\n");
		RTMP_Close(rtmp);
		RTMP_Free(rtmp);
		CleanupSockets();
		return -1;
	}

	while(nRead=RTMP_Read(rtmp,buf,bufsize)){
		fwrite(buf,1,nRead,fp);

		countbufsize+=nRead;
		RTMP_LogPrintf("Receive: %5dByte, Total: %5.2fkB\n",nRead,countbufsize*1.0/1024);
	}

	if(fp)
		fclose(fp);

	if(buf){
		free(buf);
	}

	if(rtmp){
		RTMP_Close(rtmp);
		RTMP_Free(rtmp);
		CleanupSockets();
		rtmp=NULL;
	}	
	return 0;
}

这里面包含rtmp的几个头文件，需要借助librtmp的库，可以随意在网上下个，我找了雷神的那个：

http://download.csdn.net/download/leixiaohua1020/8291757

我只拷贝了librtmp，和顶层的Makefile，Makefile做了一点点修改来编译rtmp2flv.c

Makefile：

VERSION=v2.3

prefix=/usr/local

CC=$(CROSS_COMPILE)gcc
LD=$(CROSS_COMPILE)ld

SYS=posix
#SYS=mingw

CRYPTO=OPENSSL
#CRYPTO=POLARSSL
#CRYPTO=GNUTLS
LIB_GNUTLS=-lgnutls -lgcrypt
LIB_OPENSSL=-lssl -lcrypto
LIB_POLARSSL=-lpolarssl
CRYPTO_LIB=$(LIB_$(CRYPTO))
DEF_=-DNO_CRYPTO
CRYPTO_DEF=$(DEF_$(CRYPTO))

DEF=-DRTMPDUMP_VERSION=\"$(VERSION)\" $(CRYPTO_DEF) $(XDEF)
OPT=-O2
CFLAGS=-Wall $(XCFLAGS) $(INC) $(DEF) $(OPT)
LDFLAGS=-Wall $(XLDFLAGS)

bindir=$(prefix)/bin
sbindir=$(prefix)/sbin
mandir=$(prefix)/man

BINDIR=$(DESTDIR)$(bindir)
SBINDIR=$(DESTDIR)$(sbindir)
MANDIR=$(DESTDIR)$(mandir)

LIBS_posix=
LIBS_mingw=-lws2_32 -lwinmm -lgdi32
LIBS=$(CRYPTO_LIB) -lz $(LIBS_$(SYS)) $(XLIBS)

THREADLIB_posix=-lpthread
THREADLIB_mingw=
THREADLIB=$(THREADLIB_$(SYS))
SLIBS=$(THREADLIB) $(LIBS)

LIBRTMP=librtmp/librtmp.a
INCRTMP=librtmp/rtmp_sys.h librtmp/rtmp.h librtmp/log.h librtmp/amf.h

EXT_posix=
EXT_mingw=.exe
EXT=$(EXT_$(SYS))

all:	$(LIBRTMP) progs

progs:	rtmp2flv rtmpdump rtmpgw rtmpsrv rtmpsuck

install:	progs
	-mkdir -p $(BINDIR) $(SBINDIR) $(MANDIR)/man1 $(MANDIR)/man8
	cp rtmpdump$(EXT) $(BINDIR)
	cp rtmpgw$(EXT) rtmpsrv$(EXT) rtmpsuck$(EXT) $(SBINDIR)
	cp rtmpdump.1 $(MANDIR)/man1
	cp rtmpgw.8 $(MANDIR)/man8
	@cd librtmp; $(MAKE) install

clean:
	rm -f *.o rtmp2flv$(EXT) rtmpdump$(EXT) rtmpgw$(EXT) rtmpsrv$(EXT) rtmpsuck$(EXT)
	@cd librtmp; $(MAKE) clean

FORCE:

$(LIBRTMP): FORCE
	@cd librtmp; $(MAKE) all

# note: $^ is GNU Make's equivalent to BSD $>
# we use both since either make will ignore the one it doesn't recognize

rtmp2flv: rtmp2flv.o $(LIBRTMP)
	$(CC) $(LDFLAGS) $^ $> -o $@$(EXT) $(LIBS)

rtmpdump: rtmpdump.o $(LIBRTMP)
	$(CC) $(LDFLAGS) $^ $> -o $@$(EXT) $(LIBS)

rtmpsrv: rtmpsrv.o thread.o $(LIBRTMP)
	$(CC) $(LDFLAGS) $^ $> -o $@$(EXT) $(SLIBS)

rtmpsuck: rtmpsuck.o thread.o $(LIBRTMP)
	$(CC) $(LDFLAGS) $^ $> -o $@$(EXT) $(SLIBS)

rtmpgw: rtmpgw.o thread.o $(LIBRTMP)
	$(CC) $(LDFLAGS) $^ $> -o $@$(EXT) $(SLIBS)

rtmp2flv.o: rtmp2flv.c $(INCRTMP) Makefile
rtmpgw.o: rtmpgw.c $(INCRTMP) Makefile
rtmpdump.o: rtmpdump.c $(INCRTMP) Makefile
rtmpsrv.o: rtmpsrv.c $(INCRTMP) Makefile
rtmpsuck.o: rtmpsuck.c $(INCRTMP) Makefile
thread.o: thread.c thread.h

./rtmp2flv运行程序

用smplayer receive.flv 来播放视频:

感谢雷神！