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• Sending video stream from NodeJS to python in real time [closed]

  17 juin 2021, par Tristan Delort

  I'm using a NodeJS server to catch a video stream through a WebRTC PeerConnection and I need to send it to a python script.

  


  I use NodeJS mainly because it's easy to use WebRTC in it and the package 'wrtc' supports RTCVideoSink and python's aiortc doesn't.

  


  I was thinking of using a named pipe with ffmpeg to stream the video stream but 3 questions arose :

  


  


  • Should I use python instead of NodeJS and completely avoid the stream through a named pipe part ? (This means there is a way to extract individual frames from a MediaStreamTrack in python)

    


  


  • If I stick with the "NodeJS - Python" approach, how do I send the stream from one script to the other ? Named pipe ? Unix domain sockets ? And with FFMpeg ?

    


  


  • Finally, for performance purpose I think that sending a stream and not each individual frames is better and simpler but is this true ?

    


  


  


  Thanks all !

  


• How can I rename a file from a txt file with Windows bat file ?

  12 septembre 2022, par user1264599

  I have a batch script that renames a file to input.mkv so it can be processed by a string of other commands in the bat file with a final file called ProcessedVideo.mkv. I capture the OG file name using "dir *.mkv /b>OG_FileName.txt" before being renamed.

  


  How can I rename the final processed mkv file to the name captured in the OG_FileName.txt and maybe add "_Added-Text.mkv" as the last part of my Batch Script ? (Adding text to the file name is not that important if it is too much trouble).

  


  I really thought this would be easy but I'm defeated.

  


• Realtime video processing with javacv on Android

  7 août 2014, par moonie

  I wish to do realtime video processing on Android using opencv/javacv. My basic approach can be summarized as follow :

  onCreate(), generating a new JavaCameraView

  mCameraView = new JavaCameraView(this, mCameraIndex);
  
  mCameraView.setCvCameraViewListener(this);   
  
  setContentView(mCameraView); 

  when the user clicks a button, a ffmpegframe recorder is created

  try{
  
              final long currentTimeMillis = System.currentTimeMillis();
  
              final String appName=getString(R.string.app_name);
  
              final String galleryPath=Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES).toString();
  
              final String albumPath=galleryPath+"/"+appName;
  
              final String photoPath=albumPath+"/"+currentTimeMillis+".avi";
  
              FFmpegFrameRecorder recorder=FFmpegFrameRecorder.createDefault(photoPath, 640, 360);
  
              recorder.setFrameRate(30);
  
              recorder.start();
  
              }catch(FrameRecorder.Exception e){
  
              e.printStackTrace();
  
              }

  then for each CameraFrame, use the following code to process and save the frame

      public Mat onCameraFrame(final CvCameraViewFrame inputFrame){
  
      final Mat rgba = inputFrame.rgba();
  
      //...apply some filters on rgba
  
      if(mIsTakingVideo){
  
          try{
  
            recorder.record(MatToIplImage(rgba,640,320));           
  
          }catch(FrameRecorder.Exception {
  
              e.printStackTrace();
  
              }       
  
      }
  
      return rgba;
  
  }
  
  
  
   public IplImage MatToIplImage(Mat m){
  
    Bitmap bmp=Bitmap.createBitmap(m.width(), m.height(), Config.ARGB_8888);
  
    Utils.matToBitmap(m, bmp);
  
    IplImage image=IplImage.create(m.width(),m.height(),IPL_DEPTH_8U,1);
  
    bmp.copyPixelsToBuffer(image.getByteBuffer());
  
    return image;}

  When the user clicks the button again, the recorder is stopped and released. However the video I create is an empty video. Any idea why ?

  EDIT :
  The video was empty because the format avi is not supported on my test phone...
  Now the video is not empty but it has the following errors

  1. The recorded video has two split windows instead of just one window
  2. The color is very different from the object I recorded
  3. The play rate is too fast.