好多开发者在QT环境下实现RTMP或RTSP播放时,首先考虑到的是集成VLC,集成后,却发现VLC在延迟、断网重连、稳定性等各个方面不尽人意,无法满足上线环境需求。本文以调用大牛直播SDK(官方)的Windows平台播放端SDK为例,介绍下如何在QT下实现低延迟的RTMP|RTSP播放器,废话不多说,先上图:
大牛直播SDK有MFC的demo,所以在QT上实现播放轻车熟路,如果需要多窗口播放,也可以参考转发的demo,转发的那个4窗口预览的demo做了二次封装,调用更方便。
窗体布局不再赘述,就是个普通的6窗口布局,不得不说,QT在窗体布局这块,相对MFC真的太方便了。
考虑到大多场景下,开发者有多路播放诉求,针对这种情况,我们对player做个简单的封装:
开始播放:
bool player_wrapper::StartPlay(const std::string& url, bool is_rtsp_tcp_mode, bool is_mute)
{if (is_playing_)return false;if (!OpenPlayerHandle(url, is_rtsp_tcp_mode, is_mute))return false;player_api_->SetBuffer(player_handle_, 100);player_api_->SetMute(player_handle_, is_mute ? 1 : 0);player_api_->SetRtspAutoSwitchTcpUdp(player_handle_, true);player_api_->SetRtspTimeout(player_handle_, 10);player_api_->SetRenderWindow(player_handle_, render_wnd_);player_api_->SetRenderScaleMode(player_handle_, 1);auto ret = player_api_->StartPlay(player_handle_);if (NT_ERC_OK != ret){if (!is_recording_){player_api_->Close(player_handle_);player_handle_ = NULL;}return false;}is_playing_ = true;return true;
}
开始播放封装,调用了OpenPlayerHandle(),检查系统是不是支持特定机型硬解码,通过调用Open()接口,获取播放实例,然后进行播放前的参数设置,比如网络状态event回调、视频宽高回调、设置buffer time、RTSP的TCP-UDP模式,默认播放音量等,具体实现如下:
bool player_wrapper::OpenPlayerHandle(const std::string& url, bool is_rtsp_tcp_mode, bool is_mute)
{if (player_handle_ != NULL)return true;if (url.empty())return false;bool is_support_h264_hardware_decoder_ = NT_ERC_OK == player_api_->IsSupportH264HardwareDecoder();bool is_support_h265_hardware_decoder_ = NT_ERC_OK == player_api_->IsSupportH265HardwareDecoder();NT_HANDLE player_handle = NULL;Q_ASSERT(player_api_ != NULL);if (NT_ERC_OK != player_api_->Open(&player_handle, render_wnd_, 0, NULL)){return false;}Q_ASSERT(player_handle != NULL);player_api_->SetEventCallBack(player_handle, this, &NT_Player_SDKEventHandle);player_api_->SetVideoSizeCallBack(player_handle, this, SP_SDKVideoSizeHandle);player_api_->SetH264HardwareDecoder(player_handle, is_support_h264_hardware_decoder_ ? 1 : 0, 0);player_api_->SetH265HardwareDecoder(player_handle, is_support_h265_hardware_decoder_ ? 1 : 0, 0);player_api_->SetBuffer(player_handle, 0);player_api_->SetFastStartup(player_handle, 1);player_api_->SetRTSPTcpMode(player_handle, is_rtsp_tcp_mode ? 1 : 0);player_api_->SetMute(player_handle, is_mute ? 1 : 0);int audio_volume = 100;player_api_->SetAudioVolume(player_handle, audio_volume);if (NT_ERC_OK != player_api_->SetURL(player_handle, url.c_str())){if (!is_recording_){player_api_->Close(player_handle_);player_handle_ = NULL;}return false;}player_handle_ = player_handle;return true;
}
停止播放:
void player_wrapper::StopPlay()
{if (!is_playing_)return;player_api_->StopPlay(player_handle_);if (!is_recording_){player_api_->Close(player_handle_);player_handle_ = NULL;}is_playing_ = false;
}
Event回调:
extern "C" NT_VOID NT_CALLBACK NT_Player_SDKEventHandle(NT_HANDLE handle, NT_PVOID user_data,NT_UINT32 event_id,NT_INT64 param1,NT_INT64 param2,NT_UINT64 param3,NT_PCSTR param4,NT_PCSTR param5,NT_PVOID param6)
{if (user_data == NULL)return;auto wrapper = reinterpret_cast<player_wrapper*>(user_data);if (wrapper == NULL)return;wrapper->OnPlayerStatus(event_id, param1);
}
void player_wrapper::OnPlayerStatus(NT_UINT32 event_id, NT_INT64 param1)
{if (player_handle_ == NULL)return;if (!is_playing_ && !is_recording_){return;}if (NT_SP_E_EVENT_ID_RTSP_STATUS_CODE == event_id){int status_code = (int)param1;if (401 == status_code){//HandleVerification();}return;}if (NT_SP_E_EVENT_ID_CONNECTING == event_id|| NT_SP_E_EVENT_ID_CONNECTION_FAILED == event_id|| NT_SP_E_EVENT_ID_CONNECTED == event_id|| NT_SP_E_EVENT_ID_DISCONNECTED == event_id|| NT_SP_E_EVENT_ID_NO_MEDIADATA_RECEIVED == event_id){if (NT_SP_E_EVENT_ID_CONNECTING == event_id){OutputDebugStringA("connection status: connecting\r\n");}else if (NT_SP_E_EVENT_ID_CONNECTION_FAILED == event_id){OutputDebugStringA("connection status: connection failed\r\n");}else if (NT_SP_E_EVENT_ID_CONNECTED == event_id){OutputDebugStringA("connection status: connected\r\n");}else if (NT_SP_E_EVENT_ID_DISCONNECTED == event_id){OutputDebugStringA("connection status: disconnected\r\n");}else if (NT_SP_E_EVENT_ID_NO_MEDIADATA_RECEIVED == event_id){OutputDebugStringA("connection status: no mediadata received\r\n");}}std::unique_lock<std::recursive_mutex> lock(player_handle_mutex_);player_status_ = event_id;
}
调用封装后的播放接口,记得多实例播放环境下,Init()和UnInit()接口仅需要调用一次,测试URL可自行设置。
void frmMain::startplay()
{for (int i = 0; i < widgets.size(); ++i){if (!plays[i]){plays[i] = std::make_shared<player_wrapper>(&player_api_, (HWND)NULL,(HWND)widgets.at(i)->winId());}auto& play = plays[i];if (!play->IsPlaying()){QString play_url = "rtsp://admin:admin123456@192.168.0.121:554/cam/realmonitor?channel=1&subtype=0";if (!play->StartPlay(play_url.toStdString(), true, false)){QMessageBox::information(NULL, "播放失败!", play_url);}}}
}
void frmMain::stopplay()
{for (int i = 0; i < widgets.size(); ++i){if (!plays[i]){plays[i] = std::make_shared<player_wrapper>(&player_api_, (HWND)NULL,(HWND)widgets.at(i)->winId());}auto& play = plays[i];if (play->IsPlaying()){play->StopPlay();}widgets.at(i)->setText(QString("通道 %1").arg(i + 1));widgets.at(i)->update();}
}
窗体大小发生改变时:
void frmMain::resizeEvent(QResizeEvent* event)
{for (int i = 0; i < widgets.size(); ++i){if (!plays[i]){plays[i] = std::make_shared<player_wrapper>(&player_api_, (HWND)NULL,(HWND)widgets.at(i)->winId());}auto& play = plays[i];if (play->IsPlaying()){play->OnWindowSize(widgets.at(i)->width(), widgets.at(i)->height());}}
}
以上是QT环境下集成个低延迟的RTMP、RTSP播放的基本流程,感兴趣的开发者可酌情参考。相对MFC,QT环境下在实现更酷炫和实用的逻辑显然体验更好一些。