前言

本文主要介绍自研的RtmpStreamSender.dll，rtmp库提供接口接收裸流数据，支持将裸流数据封装为flv格式并通过rtmp协议发流。

关于rtmp协议基础介绍可查看：https://blog.csdn.net/www_dong/article/details/131026072

关于rtmp收流介绍可查看：https://blog.csdn.net/www_dong/article/details/135073488

设计

主要流程：

1. rtmp服务端启动tcp（端口:1935）监听，创建rtmp server对象；
2. rtmp客户端发起tcp连接，连接成功后等到收流；
3. rtmp服务端以动态库的形式呈现，提供SendData接口，有上层应用调用时塞入数据；
4. rtmp服务端接收数据，将数据封装为flv格式；
5. rtmp服务端将flv格式的流发送给rtmp客户端；
6. rtmp客户端将数据解复用、解码和播放；

流程

• 创建tcp、启动端口监听；

int RtmpServerThread(void* param)
{
	assert(param);
	CRtmpStreamSender* receiver = (CRtmpStreamSender*)param;
	receiver->RtmpServerWorker();
	return 0;
}

int CRtmpStreamSender::InitRtmpSession_()
{
	if (0 != ParseUrl_())
	{
		printf("parse url failed\n");
		return -1;
	}

	do
	{
		m_tcpServer = std::make_shared<ZDTcpServer>(nullptr, this);
		if (!m_tcpServer.get()
			|| 0 != m_tcpServer->TcpCreate()
			|| 0 != m_tcpServer->TcpBind(m_rtmpPort)
			|| 0 != m_tcpServer->TcpListen(5))
		{
			break;
		}
			
		m_command = std::make_shared<CRtmpServerCommand>(m_tcpServer);
		if (!m_command.get()
			|| 0 != m_command->Create())
		{
			break;
		}

		m_thread = std::thread(RtmpServerThread, this);
		return 0;
	} while (0);
	
	Stop();
	return 0;
}

// 在线程中等待连接
void CRtmpStreamSender::RtmpServerWorker()
{
	bool bAccept = false;
	while (m_running)
	{
		if (!bAccept)
		{
			if (0 == m_tcpServer->TcpAccept())
			{
				bAccept = true;
			}

			continue;
		}

		std::this_thread::sleep_for(std::chrono::seconds(5));
	}
}

• 创建rtmp server

// CRtmpServerCommand:librtmp封装类
m_command = std::make_shared<CRtmpServerCommand>(m_tcpServer);
if (!m_command.get()
    || 0 != m_command->Create())
{
    break;
}

// 创建rtmp server
int CRtmpServerCommand::Create()
{
    // 创建flv复用对象
	m_flvMuxer = flv_muxer_create(SendRtmpDataMutexFLV, this);
	if (!m_flvMuxer)
		return -1;

	struct rtmp_server_handler_t handler;
	memset(&handler, 0, sizeof(handler));
	handler.send = SendCallback;

    // 创建rtmp server
	m_rtmp = rtmp_server_create(this, &handler);
	if (!m_rtmp)
		return -1;

	return 0;
}

• 数据封装

// 上层通过SendData塞数据
int CRtmpStreamSender::SendData(void* data, int len, char* codec)
{
	if (!m_command.get())
		return -1;

	return m_command->InputData(data, len, codec);
}

// 数据做flv封装
int CRtmpServerCommand::InputData(void* data, int len, const std::string& codec)
{
	if (!m_flvMuxer || !data || len <= 0 || codec.empty())
		return -1;

	int ret = -1;
	if (0 == codec.compare("H264"))
	{
		ret = flv_muxer_avc(m_flvMuxer, data, len, 0, 0);
	}
	else if (0 == codec.compare("H265"))
	{
		ret = flv_muxer_hevc(m_flvMuxer, data, len, 0, 0);
	}
	else if (0 == codec.compare("AAC"))
	{
		ret = flv_muxer_aac(m_flvMuxer, data, len, 0, 0);
	}

	return 0;
}

• 发送数据

int CRtmpServerCommand::Package(int type, const void* data, size_t bytes, uint32_t timestamp)
{
	if (!m_rtmp || !data || bytes <= 0)
		return -1;

	int ret = -1;
	if (FLV_TYPE_AUDIO == type)
	{
		ret = rtmp_server_send_audio(m_rtmp, data, bytes, timestamp);
	}
	else if (FLV_TYPE_VIDEO == type)
	{
		ret = rtmp_server_send_video(m_rtmp, data, bytes, timestamp);
	}
	else if (FLV_TYPE_SCRIPT == type)
	{
		ret = rtmp_server_send_script(m_rtmp, data, bytes, timestamp);
	}

	if (0 != ret)
		return ret;

	return 0;
}

• 资源销毁

void CRtmpServerCommand::Destroy()
{
	if (m_rtmp)
	{
		rtmp_server_destroy(m_rtmp);
		m_rtmp = nullptr;
	}

	if (m_flvMuxer)
	{
		flv_muxer_destroy(m_flvMuxer);
		m_flvMuxer = nullptr;
	}
}