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

  5 juin 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

• Unwarping 180 VR Footage with FFmpeg v360 Filter

  5 avril 2021, par Ted Wilmont

  I am struggling at present. I have searched high and low for days and can't find a command that achieves what we want to do.

  


  We have stereoscopic 180 degrees VR footage in a side-by-side equirectangular format that we want to convert to flat so we can process using further AI software.

  


  We have already split the file in half across the width using FFmpeg so we have a "right" eye and a "left" eye video file.

  


  For each video file, we need to convert the 180-degree equirectangular footage to a flat, unwarped video file using FFmpeg (and the v360 filter).

  


  We've tried the following for example :

  


  ffmpeg -i 2LEFT.mp4 -vf "v360=input=equirect:ih_fov=180:iv_fov=180:output=flat" 2LEFTTEST.mp4


  


  However, this results in a very warped/misaligned video.

  


  Some command examples, tips, suggestions as to convert the now monoscopic 180-degree equirectangular footage to a flat video file will be greatly appreciated.

  


  Thank you for your help in advance.

  


• Anomalie #3024 (Nouveau) : spip_loader.php et IE8 (oui.... les pros du C/S traditionnels l’exigent !)

  10 juillet 2013, par YannX spip

  Le lancement de spip_loader.php boucle sur le :
  spip_loader.php ?etape=fichier&chemin=spip/stable/spip-3.0.zip&dest=&range=0
  (il se reactive en restant toujours à range=0 !!)

  P.S.N’oubliez pas qu’en entreprises, et surtout dans les administrations,
  un vieil IE reste obligatoire pour certains programmes applicatifs...
  (helas, mais impossible à renverser..)