开始

public void onLiveStreamTranscoderCreate (ILiveStreamTranscoder liveStreamTranscoder, IMediaStream stream)
{
      getLogger().info("ModuleTranscoderOverlayExample#TranscoderCreateNotifierExample.onLiveStreamTranscoderCreate["+appInstance.getContextStr()+"]: "+stream.getName());
      ((LiveStreamTranscoder)liveStreamTranscoder).addActionListener(new TranscoderActionNotifierExample());
}
			

1. Create the class.
   

           
   class TranscoderActionNotifierExample extends LiveStreamTranscoderActionNotifyBase
   {
         TranscoderVideoDecoderNotifyExample transcoder=null;
   }
   			

2. 创建onSessionVideoEncodeSetup 方法。这里将创建TranscoderVideoDecoderNotifyExample 类, 它继承自TranscoderVideoDecoderNotifier 类. 这个类将对每一个经过系统的帧图像调用它的onBeforeScaleFrame方法
   

   public void onSessionVideoEncodeSetup(LiveStreamTranscoder liveStreamTranscoder, TranscoderSessionVideoEncode sessionVideoEncode)
   {
   	getLogger().info("ModuleTranscoderOverlayExample#TranscoderActionNotifierExample.onSessionVideoEncodeSetup["+appInstance.getContextStr()+"]");
   	TranscoderStream transcoderStream = liveStreamTranscoder.getTranscodingStream();
   	if (transcoderStream != null && transcoder==null)
   	{
   		TranscoderSession transcoderSession = liveStreamTranscoder.getTranscodingSession();
   		TranscoderSessionVideo transcoderVideoSession = transcoderSession.getSessionVideo();
   		List<TranscoderStreamDestination> alltrans = transcoderStream.getDestinations();
   		
   		int w = transcoderVideoSession.getDecoderWidth();
   		int h = transcoderVideoSession.getDecoderHeight();
   		transcoder = new TranscoderVideoDecoderNotifyExample(w,h);
   		transcoderVideoSession.addFrameListener(transcoder);
   		
   		//apply an overlay to all outputs
   		for(TranscoderStreamDestination destination:alltrans)
   		{
   			//TranscoderSessionVideoEncode sessionVideoEncode = transcoderVideoSession.getEncode(destination.getName());
   			TranscoderStreamDestinationVideo videoDestination = destination.getVideo();
   			System.out.println("sessionVideoEncode:"+sessionVideoEncode);
   			System.out.println("videoDestination:"+videoDestination);
   			if (sessionVideoEncode != null && videoDestination !=null)
   			{
   				transcoder.addEncoder(destination.getName(),sessionVideoEncode,videoDestination);
   			} 
   		}
   	}
   	return;
   }
   			

1. 创建类.
   

   class TranscoderVideoDecoderNotifyExample extends TranscoderVideoDecoderNotifyBase
   {
   }
   			

2. 增加成员变量
   

   private OverlayImage mainImage=null;private OverlayImage wowzaImage=null;
   private OverlayImage wowzaText = null;
   private OverlayImage wowzaTextShadow = null;
   List<EncoderInfo> encoderInfoList = new ArrayList<EncoderInfo>();
   AnimationEvents videoBottomPadding = new AnimationEvents();
   				

3. 增加TranscoderVideoDecoderNotifyExample 构造器
   

   public TranscoderVideoDecoderNotifyExample (int srcWidth, int srcHeight)
   {
   	int lowerThirdHeight = 70;
   }
   			

4. 增加addEncoder 方法
   

   public void addEncoder(String name, TranscoderSessionVideoEncode sessionVideoEncode, TranscoderStreamDestinationVideo destinationVideo)
   {
       encoderInfoList.add(new EncoderInfo(name, sessionVideoEncode,destinationVideo));
   }
   			

5. 增加onBeforeScaleFrame 方法。这个方法在每一个帧被注入到Transcoder插件时被调用。你可以在这里为输入流或每一个输出流添加一个图片
   

   public void onBeforeScaleFrame(TranscoderSessionVideo sessionVideo, TranscoderStreamSourceVideo sourceVideo, long frameCount)
   {
       boolean encodeSource=false;
       boolean showTime=false;
       double scalingFactor=1.0;
       synchronized(lock)
       {
           if (mainImage != null)
           {
               //does not need to be done for a static graphic, but left here to build on (transparency/animation)
               videoBottomPadding.step();
               mainImage.step();
               int sourceHeight = sessionVideo.getDecoderHeight();
               int sourceWidth = sessionVideo.getDecoderWidth();
               if(showTime)
               {
                   Date dNow = new Date( );
                   SimpleDateFormat ft = new SimpleDateFormat("hh:mm:ss");
                   wowzaText.SetText(ft.format(dNow));
                   wowzaTextShadow.SetText(ft.format(dNow));
               }
               if(encodeSource)
               {
                       //put the image onto the source
                       scalingFactor = 1.0;
                         TranscoderVideoOverlayFrame overlay = new TranscoderVideoOverlayFrame(mainImage.GetWidth(scalingFactor),
                         mainImage.GetHeight(scalingFactor), mainImage.GetBuffer(scalingFactor));
                         overlay.setDstX(mainImage.GetxPos(scalingFactor));
                         overlay.setDstY(mainImage.GetyPos(scalingFactor));
                         sourceVideo.addOverlay(overlayIndex, overlay);
               } 
               else    
               {
                   ///put the image onto each destination but scaled to fit
                   for(EncoderInfo encoderInfo: encoderInfoList)
                   {
                       int destinationHeight = encoderInfo.destinationVideo.getFrameSizeHeight();
                           scalingFactor = (double)destinationHeight/(double)sourceHeight;
                       TranscoderVideoOverlayFrame overlay = new TranscoderVideoOverlayFrame(mainImage.GetWidth(scalingFactor),
                       mainImage.GetHeight(scalingFactor), mainImage.GetBuffer(scalingFactor));
                       overlay.setDstX(mainImage.GetxPos(scalingFactor));
                       overlay.setDstY(mainImage.GetyPos(scalingFactor));
                       encoderInfo.destinationVideo.addOverlay(overlayIndex,    overlay);
                       //Add padding to the destination video i.e. pinch
                       encoderInfo.videoPadding[0] = 0; // left
                       encoderInfo.videoPadding[1] = 0; // top
                       encoderInfo.videoPadding[2] = 0; // right
                       encoderInfo.videoPadding[3] = (int)(((double)videoBottomPadding.getStepValue())*scalingFactor); // bottom
                        encoderInfo.destinationVideo.setPadding(encoderInfo.videoPadding);
                       } 
               }
           } 
       }
       return; 
   }

   encodeSource
   
   在这个模块中,你可以设置encodeSource 变量来为输入流在编码输出多个码流之前添加一个遮盖图层(encodeSource=true)或者为每一个输出码流添加遮盖图层(encodeSource=false)。这两种方法各有优缺点。
   
   
   Source (encodeSource=true):
   
   

   • Benefits: 只用在这里添加一次，所有输出流都会带上这个遮盖图层
   • Drawbacks: 图片可能会被再次拉伸而不会向你期望的那样显示，同时，字体也将不会被重画，而是向图片一样被拉伸. 如果视频将被缩小("扭曲")你可以将图片放置在原始视频窗口之外。例如,视频的原始尺寸是640 x 480，然后被扭曲为640 x 400 以为电视观看时在底部留出空白来显示图片

   
   
   Destination (encodeSource=false):
   
   

   • Benefits: 如果需要的话，你可以为每一个编码输出设置一个图片。并且字形可以适配输出流的帧图像大小绘制。同时原始视频可以被扭曲，图片也绘制在视频窗口的外面
   • Drawbacks: 每一个编码输出都要进行一次图片覆盖的工作(720p, 360p, etc.)
   
   showTime
   
   在onBeforeScaleFrame中设置showTime变量，将会把当前系统时间作为一个文本传递给wowzaText。在这里例子中，这个变量被用于用系统时间的文本来作为遮盖图层来对视频进行修饰。
   
   scalingFactor
   
   这个倍数，代表了输出流帧图像与输入流帧图像的关联关系。如果这个值为.5 意味着输出流帧图像的大小输入流帧图像大小的一半;如果这个值为2.0意味着输出流的帧图像大小是输入流帧图像大小的2倍。