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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++;
  
          }
  
      }
  
  }

• SharedLib dependency @ Mixed mode APK

  6 mars 2016, par NadavRub
  1. I am building a mixed mode Android project, the project is using the native ffmpeg
  2. The Libs are
     2.1. libavutil.so -> libavutil.so.51
     2.2. libavcodec.so -> libavcodec.so.54
     2.3. libavformat.so -> libavformat.so.54
     
  3. My Java code include the following JNI section to load the native libs :
     static
      System.loadLibrary("avutil") ;
      System.loadLibrary("avcodec") ;
      System.loadLibrary("avformat") ;
     
     
  4. ’libavcodec.so’ depends on ’libavutil.so.51’ AND NOT on ’libavutil.so’.
     
  5. When running my activity System.loadLibrary("avcodec") ; excepts with "could not load needed library ’libavutil.so.51’ for ’libavcodec.so’ (Library ’libavutil.so.51’ not found)"
  6. On my Android.mk I have the following section to have the native libs added to the APK :
     
     include $(CLEAR_VARS)
     LOCAL_MODULE := mylib
     LOCAL_SRC_FILES := ../../../mylib/libmylib.so
     include $(PREBUILT_SHARED_LIBRARY)
     
     
  7. replacing libmylib.so with libmylib.so.%some number% cause the build to fail with [LOCAL_SRC_FILES should point to a file ending with ".so"]
     
     
     Having the above in mind, how can I have libavcodec loading w/o the dependency problem ?
     
     • Can I fix libavcodec.so dependency to point to libavutil.so and not to libavutil.so.51 ?
       
     • Can I change Android.mk so it will be able to pack libavutil.so.51 ( non .SO extention ) ? will it then be loadable using ’System.loadLibrary’ ?.
       
       Any help will be appreciated !!!
       
       Nadav at Sophin
       

• mov : Trim dref absolute path

  16 février 2016, par Vittorio Giovara

  mov : Trim dref absolute path
  Samples produced by Omneon (Harmonic) store external references with
  
  paths ending with 0s. Such movs cannot be loaded properly since every
  
  0 is converted to ’/’, to keep the same parsing code for dref type 2
  
  and type 18 : this makes the external reference point to a non-existing
  
  direactory, rather than to the actual referenced file.
  Add a brief trimming loop that drops all ending 0s before trying to
  
  parse the external reference path.
  Signed-off-by : Vittorio Giovara <vittorio.giovara@gmail.com>
  

  • [DBH] libavformat/mov.c