媒体播放器

本文介绍如何调用媒体播放器相关的 API 播放本地或在线媒体资源，或将媒体资源分享给声网频道内的远端用户观看或收听。

前提条件

在进行操作之前，请确保你已经在项目中实现了基本的实时音视频功能。有关详细信息，请参考实现音视频互动。

实现方法

参考如下步骤，在你的项目中实现媒体播放功能：

1. 初始化 IRtcEngine 后，创建一个 IMediaPlayer 对象。

   C++

   void CAgoraMediaPlayer::InitMediaPlayerKit()
   {
   	// 创建声网媒体播放器
   	m_mediaPlayer = m_rtcEngine->createMediaPlayer().get();
   	m_lstInfo.InsertString(m_lstInfo.GetCount(), _T("createAgoraMediaPlayer"));
   	m_lstInfo.InsertString(m_lstInfo.GetCount(), _T("mediaplayer initialize"));
   	// 设置播放器渲染视图
   	RECT rc = { 0 };
   	m_localVideoWnd.GetWindowRect(&rc);
   	int ret = m_mediaPlayer->setView((agora::media::base::view_t)m_localVideoWnd.GetSafeHwnd());
   	// 设置接收播放器事件的窗口
   	m_mediaPlayerEvent.SetMsgReceiver(m_hWnd);
   }

2. 调用 registerPlayerSourceObserver 方法注册播放观测器。

   C++

   void CAgoraMediaPlayer::OnBnClickedButtonJoinchannel()
   {
   	...
   		// 注册播放观测器
   		ret = m_mediaPlayer->registerPlayerSourceObserver(&m_mediaPlayerEvent);
   		m_lstInfo.InsertString(m_lstInfo.GetCount(), _T("registerPlayerSourceObserver"));
   		if (0 == m_rtcEngine->joinChannel(APP_TOKEN, szChannelId.c_str(), 0, options)) {
   			strInfo.Format(_T("join channel %s, use ChannelMediaOptions"), getCurrentTime());
   		}
   	}
   	else {
   		// 取消注册播放观测器
   		ret = m_mediaPlayer->unregisterPlayerSourceObserver(&m_mediaPlayerEvent);
   		m_lstInfo.InsertString(m_lstInfo.GetCount(), _T("registerPlayerSourceObserver"));
   		//leave channel in the engine.
   		if (0 == m_rtcEngine->leaveChannel()) {
   			strInfo.Format(_T("leave channel %s"), getCurrentTime());
   		}
   	}
   	m_lstInfo.InsertString(m_lstInfo.GetCount(), strInfo);
   }

3. 实现媒体播放器观测器的回调。

   C++

   // 报告播放器状态改变
   LRESULT CAgoraMediaPlayer::OnmediaPlayerStateChanged(WPARAM wParam, LPARAM lParam)
   {
   	CString strState;
   	CString strError;
   	switch ((agora::media::base::MEDIA_PLAYER_STATE)wParam)
   	{
   	case  agora::media::base::PLAYER_STATE_OPEN_COMPLETED:
   		strState = _T("PLAYER_STATE_OPEN_COMPLETED");
   		m_mediaPlayerState = mediaPLAYER_OPEN;
   		int64_t duration;
   		m_mediaPlayer->getDuration(duration);
   		m_sldVideo.SetRangeMax((int)duration);
   
   		break;
   	...
   	}
   
   	switch ((agora::media::base::MEDIA_PLAYER_ERROR)lParam)
   	{
   	case agora::media::base::PLAYER_ERROR_URL_NOT_FOUND:
   		strError = _T("PLAYER_ERROR_URL_NOT_FOUND");
   		break;
   	...
   	}
   	CString strInfo;
   	strInfo.Format(_T("sta:%s,\nerr:%s"), strState, strError);
   	m_lstInfo.InsertString(m_lstInfo.GetCount(), strInfo);
   	return TRUE;
   }
   
   // 报告当前播放进度
   LRESULT CAgoraMediaPlayer::OnmediaPlayerPositionChanged(WPARAM wParam, LPARAM lParam)
   {
   	int64_t * p = (int64_t*)wParam;
   	m_sldVideo.SetPos((int)*p);
   	delete p;
   	return TRUE;
   }

4. 加入频道前，设置媒体播放器 ID，发布媒体播放器的音视频，将媒体资源分享给声网频道内的远端用户。

   C++

   void CAgoraMediaPlayer::OnBnClickedButtonPublishVideo()
   {
   	if (m_publishMeidaplayer) {
   		ChannelMediaOptions op;
   		op.clientRoleType = CLIENT_ROLE_BROADCASTER;
   		op.publishMediaPlayerVideoTrack = false;
   		op.publishMediaPlayerAudioTrack = false;
   		op.publishMediaPlayerId = m_mediaPlayer->getMediaPlayerId();
   		int ret = m_rtcEngine->updateChannelMediaOptions(op);
   		ChannelMediaOptions op2;
   		op2.clientRoleType = CLIENT_ROLE_BROADCASTER;
   		op2.publishCameraTrack = true;
   		ret = m_rtcEngine->updateChannelMediaOptions(op2);
   		m_publishMeidaplayer = false;
   	}
   	else {
   		ChannelMediaOptions options;
   		options.clientRoleType = CLIENT_ROLE_BROADCASTER;
   		options.publishMediaPlayerVideoTrack = true;
   		options.publishMediaPlayerAudioTrack = true;
   		options.publishMediaPlayerId = m_mediaPlayer->getMediaPlayerId();
   		options.publishCameraTrack = false;
   		options.publishAudioTrack = false;
   		options.autoSubscribeAudio = false;
   		options.autoSubscribeVideo = false;
   		m_rtcEngine->updateChannelMediaOptions(options);
   		m_publishMeidaplayer = true;
   	}
   }
   

5. 打开本地或在线媒体文件。

   C++

   void CAgoraMediaPlayer::OnBnClickedButtonOpen()
   {
   	CString strUrl;
   	CString strInfo;
   	m_edtVideoSource.GetWindowText(strUrl);
   	std::string tmp = cs2utf8(strUrl);
   	switch (m_mediaPlayerState)
   	{
   	case mediaPLAYER_READY:
   	case mediaPLAYER_STOP:
   
   		if (tmp.empty())
   		{
   			AfxMessageBox(_T("you can fill video source."));
   			return;
   		}
   		// 打开媒体文件
   		m_mediaPlayer->open(tmp.c_str(), 0);
   		break;
   	default:
   		m_lstInfo.InsertString(m_lstInfo.GetCount(), _T("can not open player."));
   		break;
   	}
   }
   

6. 播放媒体文件。

   注意

   请在收到 onPlayerSourceStateChanged 回调报告播放状态为 PLAYER_STATE_OPEN_COMPLETED 后再调用 play 方法播放媒体文件。

   C++

   void CAgoraMediaPlayer::OnBnClickedButtonPlay()
   {
       int ret;
       switch (m_mediaPlayerState)
       {
       case mediaPLAYER_PAUSE:
       case mediaPLAYER_OPEN:
           // 播放媒体文件
           ret = m_mediaPlayer->play();
           if (ret == 0)
           {
               m_mediaPlayerState = mediaPLAYER_PLAYING;
           }
           break;
       case mediaPLAYER_PLAYING:
           // 暂停播放
           ret = m_mediaPlayer->pause();
           if (ret == 0)
           {
               m_mediaPlayerState = mediaPLAYER_PAUSE;
           }
           break;
       default:
           break;
       }
   }

7. 当用户离开频道时，停止播放、销毁媒体播放器、取消注册播放观测器，并销毁分配的资源。

   C++

   void CAgoraMediaPlayer::OnBnClickedButtonStop()
   {
   	if (m_mediaPlayerState == mediaPLAYER_OPEN ||
   		m_mediaPlayerState == mediaPLAYER_PLAYING ||
   		m_mediaPlayerState == mediaPLAYER_PAUSE)
   	{
   		// 停止播放
   		m_mediaPlayer->stop();
   		m_mediaPlayerState = mediaPLAYER_STOP;
   	}
   }
   
   void CAgoraMediaPlayer::OnDestroy()
   {
       // 销毁媒体播放器
   	CDialogEx::OnDestroy();
   	UnInitMediaPlayerKit();
   }
   

参考信息

本节介绍本文中使用方法的更多信息以及相关页面的链接。

示例项目

声网在 GitHub 上提供了一个开源的示例项目MediaPlayer，你可以前往下载，或查看其中的源代码。

API 参考

• createMediaPlayer
• destroyMediaPlayer
• registerPlayerSourceObserver
• unregisterPlayerSourceObserver
• getMediaPlayerId
• open
• play
• pause
• stop
• onPlayerSourceStateChanged
• onPositionChanged