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• How to update a byte array in a method, without running it again ?

  18 février 2016, par AR792

  I have a class(an AsyncTask) which does image processing and generates yuv bytes continously, at around 200ms interval.

  Now I send these yuv bytes to another method where the they are recorded using FFmpeg frame recorder :

  public void recordYuvData() {
  
  
  
          byte[] yuv = getNV21();
  
          System.out.println(yuv.length + "  returned yuv bytes  ");
  
          if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
  
              startTime = System.currentTimeMillis();
  
              return;
  
          }
  
          if (RECORD_LENGTH > 0) {
  
              int i = imagesIndex++ % images.length;
  
              yuvimage = images[i];
  
              timestamps[i] = 1000 * (System.currentTimeMillis() - startTime);
  
          }
  
          /* get video data */
  
          if (yuvimage != null && recording) {
  
              ((ByteBuffer) yuvimage.image[0].position(0)).put(yuv);
  
  
  
              if (RECORD_LENGTH <= 0) {
  
                  try {
  
                      long t = 1000 * (System.currentTimeMillis() - startTime);
  
                      if (t > recorder.getTimestamp()) {
  
                          recorder.setTimestamp(t);
  
                      }
  
                      recorder.record(yuvimage);
  
                  } catch (FFmpegFrameRecorder.Exception e) {
  
  
  
                      e.printStackTrace();
  
                  }
  
              }
  
          }
  
      }

  This method ; recordYuvData() is initiated on button click.

  1. If I initiate it only once , then only the initial image gets recorded, rest are not.

  2. If I initiate this each time after the end of the image processing it records but leads to ’weird’ fps count of the video ; and finally this leads to application crash after sometime.

     For above what I feel is, at the end of image processing a new instance of recordYuvData() is created without ending the previous one, accumulating many instances of recordYuvData(). [correct me if I am wrong]

  So, how do I update ’ONLY’ yuv bytes in the method without running it again ?

  Thanks....!

  Edit :

  On Click :

      record.setOnClickListener(new View.OnClickListener() {
  
          @Override
  
          public void onClick(View v) {
  
              recordYuvdata();
  
              startRecording();

  getNV21()

  byte[] getNV21(Bitmap bitmap) {
  
  
  
      int inputWidth = 1024;
  
      int inputHeight = 640;
  
      int[] argb = new int[inputWidth * inputHeight];
  
  
  
      bitmap.getPixels(argb, 0, inputWidth, 0, 0, inputWidth, inputHeight);
  
      System.out.println(argb.length + "@getpixels ");
  
  
  
  
  
      byte[] yuv = new byte[inputWidth * inputHeight * 3 / 2];
  
      encodeYUV420SP(yuv, argb, inputWidth, inputHeight);
  
  
  
      return yuv;
  
  
  
  }
  
  
  
  void encodeYUV420SP(byte[] yuv420sp, int[] argb, int width, int height) {
  
      final int frameSize = width * height;
  
  
  
      int yIndex = 0;
  
      int uvIndex = frameSize;
  
      System.out.println(yuv420sp.length + " @encoding " + frameSize);
  
  
  
      int a, R, G, B, Y, U, V;
  
      int index = 0;
  
      for (int j = 0; j < height; j++) {
  
          for (int i = 0; i < width; i++) {
  
  
  
              a = (argb[index] & 0xff000000) >> 24; // a is not used obviously
  
              R = (argb[index] & 0xff0000) >> 16;
  
              G = (argb[index] & 0xff00) >> 8;
  
              B = (argb[index] & 0xff) >> 0;
  
  
  
              // well known RGB to YUV algorithm
  
  
  
              Y = ((66 * R + 129 * G + 25 * B + 128) >> 8) + 16;
  
              U = ((-38 * R - 74 * G + 112 * B + 128) >> 8) + 128;
  
              V = ((112 * R - 94 * G - 18 * B + 128) >> 8) + 128;
  
  
  
              // NV21 has a plane of Y and interleaved planes of VU each sampled by a factor of 2
  
              //    meaning for every 4 Y pixels there are 1 V and 1 U.  Note the sampling is every other
  
              //    pixel AND every other scanline.
  
              yuv420sp[yIndex++] = (byte) ((Y < 0) ? 0 : ((Y > 255) ? 255 : Y));
  
              if (j % 2 == 0 && index % 2 == 0) {
  
                  yuv420sp[uvIndex++] = (byte) ((V < 0) ? 0 : ((V > 255) ? 255 : V));
  
                  yuv420sp[uvIndex++] = (byte) ((U < 0) ? 0 : ((U > 255) ? 255 : U));
  
              }
  
  
  
              index++;
  
          }
  
      }
  
  }

• Running Live streaming of local user using ffmpeg at Web plateform

  23 décembre 2019, par Sneha Makwana

  I am using below command to stream my live desktop screen.

  ffmpeg -f x11grab -r 1 -loglevel panic -s `xdpyinfo | grep 'dimensions:'|awk '{print $2}'` -i $DISPLAY -qscale 0 -f mpegts udp://192.168.3.151:1111

  udp ://192.168.3.151:1111 - this is my streaming URL

  I can see live streaming in the parole media player (in Linux platform), but I can’t see this in a cross-network (i.e from windows PC - in the same network)

  Is there any web platform so I can see my streaming from anywhere (either windows or linux) just using unique streaming URL or do I need to change my streaming command or method ?

  Any help is much appreciated

• Running an .exe on cmd line from a visual studio c++ project

  28 novembre 2017, par Pop24

  BACKGROUND

  I have a visual studio c++ project "VideoAnalyser" which analyses a video for specific features based predominantly on OPENCV.

  I now want to run this project against a large directory of video files. The issue I have is that they must first be converted to .avi file format in order to utilise the OPENCV functions within my project. I can do this with FFMPEG. It is a large directory and i do not want to create duplicates of every video file with the format changed. Rather, I’d take the video file, convert it, then run the "Video Analyser" against it destroy the reformatted file and then move onto the next video file and repeat. I can run FFMPEG independantly on the command line with no issues, however I’m unsure how to integrate this into my "Video Analyser" project which leads to...

  MY QUESTION

  How do I get my "VideoAnalyser" c++ project to run the FFMPEG exectuable through the cmd line ?