技術背景
我們在對接RTSP播放器相關的技術訴求的時候,遇到這樣的需求,客戶做特種設備巡檢的,需要把攝像頭拍到的RTSP流拉下來,然后添加動態水印后,再生成新的RTSP URL,供平臺調用。真個流程需要延遲盡可能的低,分辨率要支持到1080p,并需要把添加過動態水印的數據,保存到本地。
技術實現
在此之前,大牛直播SDK有非常成熟的RTSP播放、輕量級RTSP服務和錄像模塊,要做的就是,拉取到RTSP流后,把解碼后的YUV或RGB回調給上層,上層通過圖層的形式,添加動態文字水印(圖片水印亦可),然后,投遞給輕量級RTSP服務,RTSP服務對外提供個拉流的RTSP URL,無圖無真相:
左側就是我們基于Windows平臺C#的播放器的demo,二次開發的,添加了軟、硬編碼設置(考慮到分辨率比較高,添加支持了硬編碼選項設置)、動態水印設置、輕量級RTSP服務、實時錄像和RTMP推送。
先說數據回調,本文以回調yuv數據為例:
video_frame_call_back_ = new SP_SDKVideoFrameCallBack(SetVideoFrameCallBack);
NTSmartPlayerSDK.NT_SP_SetVideoFrameCallBack(player_handle_, (Int32)NT.NTSmartPlayerDefine.NT_SP_E_VIDEO_FRAME_FORMAT.NT_SP_E_VIDEO_FRAME_FORMAT_RGB32, IntPtr.Zero, video_frame_call_back_);
回調后的數據,投遞到輕量級RTSP服務模塊。
public void SetVideoFrameCallBack(IntPtr handle, IntPtr userData, UInt32 status, IntPtr frame){if (frame == IntPtr.Zero){return;}NT_SP_VideoFrame video_frame = (NT_SP_VideoFrame)Marshal.PtrToStructure(frame, typeof(NT_SP_VideoFrame));if (publisher_wrapper_ != null){if (publisher_wrapper_.IsPublisherHandleAvailable()){if (publisher_wrapper_.IsPublishing() || publisher_wrapper_.IsRecording() || publisher_wrapper_.IsRTSPPublisherRunning()){//publisher_wrapper_.OnPostRGB32Data(0, video_frame.plane0_, video_frame.width_ * 4 * video_frame.height_, video_frame.stride0_,// video_frame.width_, video_frame.height_);publisher_wrapper_.OnPostYUVData(0, video_frame.plane0_, video_frame.stride0_, video_frame.plane1_, video_frame.stride1_,video_frame.plane2_, video_frame.stride2_,video_frame.width_, video_frame.height_);}}}}
音頻由于暫時不要二次處理,直接投遞過去,如果需要處理的話,處理后再投遞給publisher wrapper:
public void SetAudioPCMFrameCallBack(IntPtr handle, IntPtr user_data,UInt32 status, IntPtr data, UInt32 size,Int32 sample_rate, Int32 channel, Int32 per_channel_sample_number){if (data == IntPtr.Zero || size == 0){return;}if (publisher_wrapper_ != null){if (publisher_wrapper_.IsPublisherHandleAvailable()){if (publisher_wrapper_.IsPublishing() || publisher_wrapper_.IsRecording() || publisher_wrapper_.IsRTSPPublisherRunning()){publisher_wrapper_.OnPostAudioPCMData(data, size, 0, sample_rate, channel, per_channel_sample_number);}}}}
設置文字水印字體:
private void btn_set_font_Click(object sender, EventArgs e){FontDialog font_dlg = new FontDialog();DialogResult result = font_dlg.ShowDialog();if (result == DialogResult.OK){// 獲取用戶所選字體Font selectedFont = font_dlg.Font;btn_set_font.Text = "" + selectedFont.Name + ", " + selectedFont.Size + "pt";selected_osd_font_ = new Font(selectedFont.Name, selectedFont.Size, FontStyle.Regular, GraphicsUnit.Point);}}
動態設置文字水印:
private async void btn_text_osd_Click(object sender, EventArgs e){string format = "yyyy-MM-dd HH:mm:ss.fff";StringBuilder sb = new StringBuilder();sb.Append("施工單位:上海視沃信息科技有限公司(daniusdk.com)");sb.Append("\r\n");sb.Append("施工時間:");sb.Append(DateTime.Now.DayOfWeek.ToString());sb.Append(" ");sb.Append(DateTime.Now.ToString(format));sb.Append("\r\n");sb.Append("當前位置:上海市");string str = sb.ToString();Bitmap bmp = GenerateBitmap(str);int index = 1;int x = 0;int y = 200;UpdateLayerRegion(index, x, y, bmp);await Task.Delay(30);UpdateARGBBitmap(index, bmp);}
如果需要硬編碼:
if (btn_check_video_hardware_encoder_.Checked){is_hw_encoder = true;}Int32 cur_sel_encoder_id = 0;Int32 cur_sel_gpu = 0;if (is_hw_encoder){int cur_sel_hw = combobox_video_encoders_.SelectedIndex;if (cur_sel_hw >= 0){cur_sel_encoder_id = Convert.ToInt32(combobox_video_encoders_.SelectedValue);cur_sel_gpu = -1;int cur_sel_hw_dev = combobox_video_hardware_encoder_devices_.SelectedIndex;if (cur_sel_hw_dev >= 0){cur_sel_gpu = Convert.ToInt32(combobox_video_hardware_encoder_devices_.SelectedValue);}}else{is_hw_encoder = false;}}if (!is_hw_encoder){if ((int)NTCommonMediaDefine.NT_MEDIA_CODEC_ID.NT_MEDIA_CODEC_ID_H264 == cur_video_codec_id){cur_sel_encoder_id = btn_check_openh264_encoder_.Checked ? 1 : 0;}}publisher_wrapper_.SetVideoEncoder((int)(is_hw_encoder ? 1 : 0), (int)cur_sel_encoder_id, (uint)cur_video_codec_id, (int)cur_sel_gpu);publisher_wrapper_.SetVideoQualityV2(publisher_wrapper_.CalVideoQuality(width_, height_, is_h264_encoder));publisher_wrapper_.SetVideoBitRate(publisher_wrapper_.CalBitRate(video_fps_, width_, height_));publisher_wrapper_.SetVideoMaxBitRate(publisher_wrapper_.CalMaxKBitRate(video_fps_, width_, height_, false));publisher_wrapper_.SetVideoKeyFrameInterval(key_frame_interval_);if (is_h264_encoder){publisher_wrapper_.SetVideoEncoderProfile(1);}publisher_wrapper_.SetVideoEncoderSpeed(publisher_wrapper_.CalVideoEncoderSpeed(width_, height_, is_h264_encoder));
啟動停止RTSP服務:
private void btn_rtsp_service_Click(object sender, EventArgs e){if(publisher_wrapper_.IsRTSPSerivceRunning()){publisher_wrapper_.StopRtspService();btn_rtsp_service.Text = "啟動RTSP服務";btn_rtsp_stream.Enabled = false;}else{if(publisher_wrapper_.StartRtspService()){btn_rtsp_service.Text = "停止RTSP服務";btn_rtsp_stream.Enabled = true;}}}
發布RTSP流:
private void btn_rtsp_stream_Click(object sender, EventArgs e){if (publisher_wrapper_.IsRTSPPublisherRunning()){publisher_wrapper_.StopRtspStream();btn_rtsp_stream.Text = "發布RTSP流";btn_get_rtsp_session_numbers.Enabled = false;btn_rtsp_service.Enabled = true;}else{if (!publisher_wrapper_.IsPublisherHandleAvailable()){if (!OpenPublisherHandle()){return;}}if (publisher_wrapper_.GetPublisherHandleCount() < 1){SetCommonOptionToPublisherSDK();}if (!publisher_wrapper_.StartRtspStream()){MessageBox.Show("調用StartRtspStream失敗..");return;}btn_rtsp_stream.Text = "停止RTSP流";btn_get_rtsp_session_numbers.Enabled = true;btn_rtsp_service.Enabled = false;}}
獲取RTSP會話數:
private void btn_get_rtsp_session_numbers_Click(object sender, EventArgs e){if (publisher_wrapper_.IsRTSPPublisherRunning()){int session_numbers = publisher_wrapper_.GetRtspSessionNumbers();MessageBox.Show(session_numbers.ToString(), "當前RTSP連接會話數");}}
本地錄像:
private void btn_start_recorder_Click(object sender, EventArgs e){if (!publisher_wrapper_.IsPublisherHandleAvailable()){if (!OpenPublisherHandle()){return;}}if (publisher_wrapper_.GetPublisherHandleCount() < 1){SetCommonOptionToPublisherSDK();}if (!publisher_wrapper_.StartRecorder()){MessageBox.Show("調用StartRecorder失敗..");return;}btn_start_recorder.Enabled = false;btn_stop_recorder.Enabled = true;}private void btn_stop_recorder_Click(object sender, EventArgs e){if (!publisher_wrapper_.IsPublisherHandleAvailable())return;if (publisher_wrapper_.IsRecording()){publisher_wrapper_.StopRecorder();btn_start_recorder.Enabled = true;btn_stop_recorder.Enabled = false;}}
暫停錄像、恢復錄像:
private void btn_pause_recorder_Click(object sender, EventArgs e){if (!publisher_wrapper_.IsPublisherHandleAvailable()){return;}String btn_pause_rec_text = btn_pause_recorder.Text;if ("暫停錄像" == btn_pause_rec_text){UInt32 ret = publisher_wrapper_.PauseRecorder(true);if ((UInt32)NT.NTSmartPublisherDefine.NT_PB_E_ERROR_CODE.NT_ERC_PB_NEED_RETRY == ret){MessageBox.Show("暫停錄像失敗, 請重新嘗試!");return;}else if (NTBaseCodeDefine.NT_ERC_OK == ret){btn_pause_recorder.Text = "恢復錄像";}}else{UInt32 ret = publisher_wrapper_.PauseRecorder(false);if ((UInt32)NT.NTSmartPublisherDefine.NT_PB_E_ERROR_CODE.NT_ERC_PB_NEED_RETRY == ret){MessageBox.Show("恢復錄像失敗, 請重新嘗試!");return;}else if (NTBaseCodeDefine.NT_ERC_OK == ret){btn_pause_recorder.Text = "暫停錄像";}}}
推送RTMP:
private void btn_publish_rtmp_Click(object sender, EventArgs e){if (!publisher_wrapper_.IsPublisherHandleAvailable()){if (!OpenPublisherHandle()){return;}}if (publisher_wrapper_.GetPublisherHandleCount() < 1){SetCommonOptionToPublisherSDK();}String url = "rtmp://192.168.0.108:1935/hls/stream1";if (url.Length < 8){publisher_wrapper_.Close();MessageBox.Show("請輸入推送地址");return;}if (!publisher_wrapper_.StartPublisher(url)){MessageBox.Show("調用StartPublisher失敗..");return;}btn_publish_rtmp.Enabled = false;btn_stop_publish_rtmp.Enabled = true;}private void btn_stop_publish_rtmp_Click(object sender, EventArgs e){if (!publisher_wrapper_.IsPublisherHandleAvailable())return;if (publisher_wrapper_.IsPublishing()){publisher_wrapper_.StopPublisher();btn_publish_rtmp.Enabled = true;btn_stop_publish_rtmp.Enabled = false;}}
圖層設計,目前設計兩個圖層,一個是原始YUV底層,另外一個是文字水印圖層,如果需要動態去除文字水印,只要index為1的圖層,enable設置為0即可。
NTSmartPublisherSDK.NT_PB_ClearLayersConfig(publisher_handle_, 0,0, IntPtr.Zero);if (video_option_ == (uint)NTSmartPublisherDefine.NT_PB_E_VIDEO_OPTION.NT_PB_E_VIDEO_OPTION_LAYER){NT_PB_ExternalVideoFrameLayerConfig external_layer_c0 = new NT_PB_ExternalVideoFrameLayerConfig();external_layer_c0.base_.type_ = (Int32)NTSmartPublisherDefine.NT_PB_E_LAYER_TYPE.NT_PB_E_LAYER_TYPE_EXTERNAL_VIDEO_FRAME;external_layer_c0.base_.index_ = 0;external_layer_c0.base_.enable_ = 1;external_layer_c0.base_.region_.x_ = 0;external_layer_c0.base_.region_.y_ = 0;external_layer_c0.base_.region_.width_ = video_width_;external_layer_c0.base_.region_.height_ = video_height_;external_layer_c0.base_.offset_ = Marshal.OffsetOf(external_layer_c0.GetType(), "base_").ToInt32();external_layer_c0.base_.cb_size_ = (uint)Marshal.SizeOf(external_layer_c0);IntPtr external_layer_conf0 = Marshal.AllocHGlobal(Marshal.SizeOf(external_layer_c0));Marshal.StructureToPtr(external_layer_c0, external_layer_conf0, true);UInt32 external_r0 = NTSmartPublisherSDK.NT_PB_AddLayerConfig(publisher_handle_, 0,external_layer_conf0, (int)NTSmartPublisherDefine.NT_PB_E_LAYER_TYPE.NT_PB_E_LAYER_TYPE_EXTERNAL_VIDEO_FRAME,0, IntPtr.Zero);Marshal.FreeHGlobal(external_layer_conf0);//OSD水印層NT_PB_ExternalVideoFrameLayerConfig external_layer_c1 = new NT_PB_ExternalVideoFrameLayerConfig();external_layer_c1.base_.type_ = (Int32)NTSmartPublisherDefine.NT_PB_E_LAYER_TYPE.NT_PB_E_LAYER_TYPE_EXTERNAL_VIDEO_FRAME;external_layer_c1.base_.index_ = 1;external_layer_c1.base_.enable_ = 1;external_layer_c1.base_.region_.x_ = 0;external_layer_c1.base_.region_.y_ = 200;external_layer_c1.base_.region_.width_ = 200;external_layer_c1.base_.region_.height_ = 200;external_layer_c1.base_.offset_ = Marshal.OffsetOf(external_layer_c1.GetType(), "base_").ToInt32();external_layer_c1.base_.cb_size_ = (uint)Marshal.SizeOf(external_layer_c1);IntPtr external_layer_conf = Marshal.AllocHGlobal(Marshal.SizeOf(external_layer_c1));Marshal.StructureToPtr(external_layer_c1, external_layer_conf, true);UInt32 external_r1 = NTSmartPublisherSDK.NT_PB_AddLayerConfig(publisher_handle_, 0,external_layer_conf, (int)NTSmartPublisherDefine.NT_PB_E_LAYER_TYPE.NT_PB_E_LAYER_TYPE_EXTERNAL_VIDEO_FRAME,0, IntPtr.Zero);Marshal.FreeHGlobal(external_layer_conf);//end}
總結
RTSP拉流二次編碼,整體邏輯不復雜,就是把數據回調后,二次處理,我們推送端設計的是圖層的形式,所以,回調后的數據,直接作為第0層,文字水印作為第一層,如果需要圖片水印,圖片水印作為第三層即可。RTSP拉流二次編碼,如果做到客戶端盡量無感知,需要盡可能的壓縮整體處理的延遲,確保從數據采集,到二次處理,到再次播放出來毫秒級,滿足絕大多數場景下的技術需求。