Recherche avancée

Sur d’autres sites (8815)

• Revision 33402 : Amélioration du pipeline post édition

  29 novembre 2009, par kent1@… — Log

  Amélioration du pipeline post édition

• ffmpeg - overlay a video with rounded corners

  4 novembre 2019, par asi

  I am successfully using overlaying a scaled (smaller) video on top of a larger one but am struggling to understand how could I give the small video a rounded corners mask.

  Edit

  thanks to @loogan comment I’ve managed to get a working command that created applies a circular mask :

  ffmpeg 
  
      -i main.mp4 
  
      -i vignette.mp4 
  
      -filter_complex 
  
        [1:v]scale=300:-1[scaled];
  
        [scaled]split [scaled0][scaled11]; 
  
        [scaled0]trim=end_frame=1,geq='st(3,pow(X-(W/2),2)+pow(Y-(H/2),2));if(lte(ld(3),780*780),255,0)':3:3,loop=-1:1,setpts=N/FRAME_RATE/TB[mask];
  
      [scaled1][mask]alphamerge[cutout];
  
      [0][cutout]overlay=x=W-w:y=0[v];
  
      -map [v] 
  
      -map [a]  
  
      output.mp4

  but how to get from a circle to a rounded rect still eludes me. cant quite get what are the params that geq expects and the math to generate them.

  assuming that the video that needs masking is 200 * 300 and the corners should have a 5px radius, is there a geq command that can create this mask ? maybe en ellipse ?

  or maybe a better way would be to use a pre-made png as a mask ?

  any insights welcome

• How to stream live video from DJI Professional 3 camera ?

  29 avril 2017, par raullalves

  I have to get the live stream video from DJI Phantom 3 camera in my C++ application, in order to do a Computer Vision processing in OpenCV.

  First I tried sending the H264 raw data through an UDP socket, inside this callback :

          mReceivedVideoDataCallBack = new CameraReceivedVideoDataCallback() {
  
  
  
          @Override
  
          public void onResult(byte[] videoBuffer, int size) {
  
              //Here, I call a method from a class I created, that sends the buffer through UDP
  
              if (gravar_trigger) controleVideo.enviarFrame(videoBuffer, size);
  
  
  
              if (mCodecManager != null)  mCodecManager.sendDataToDecoder(videoBuffer, size);
  
  
  
          }
  
  
  
      };

  That communication above works well. However, I haven’t been able to decode that UDP H264 data in my C++ desktop application. I have tested with FFmpeg lib, but couldn’t get to alocate an AVPacketwith my UDP data, in order to decode using avcodec_send_packet and avcodec_receive_frame. I also had problems with AVCodecContext, since my UDP communication wasn’t a stream like RTSP, where it could get information about its source. Therefore, I had to change how I was trying to solve the problem.

  Then, I found libstreaming, in which can be associate to stream the android video camera to a Wowza Server, creating something like a RTSP stream connection, where the data could be obtained in my final C++ application easily using OpenCV videoCapture. However, libstreaming uses its own surfaceView. In other words, I would have to link the libstreaming surfaceView with the DJI Drone’s videoSurface. I’m really new to Android, so don’t have any clue of how to do that.

  To sum up, is that the correct approach ? Someone has a better idea ? Thanks in advance