Recherche avancée

Sur d’autres sites (9186)

• how to find video and audio stream times without the deprecated values ? libav 10.5

  23 novembre 2014, par Narayana James Emery

  After looking into the documentation, AVStream.pts has been deprecated. Before I was using this loop to try and get the video and audio time. it’s the same as whats in the api-example.c (which no longer works) :

  if (audioStream_)
  
      {
  
          VideoTime = (double)videoStream_->pts.val*videoStream_->time_base.num/videoStream_->time_base.den;
  
          do
  
          {
  
              AudioTime = (double)audioStream_->pts.val*audioStream_->time_base.num/audioStream_->time_base.den;
  
              ret = WriteAudioFrame();
  
          }
  
          while (AudioTime < VideoTime && ret);
  
          if (ret < 0)
  
              return ret;
  
      }

  what is the current alternative ? I haven’t been able to get anything to work as of yet and I’ve been searching for around 3 hours.

• optimizing ffmpeg in windows platform for processing with web-cam

  22 août 2013, par user2320537

  I have to develop a tool in java that will capture frames from webcam, Now what I have done for that is, I have used Runtime class to run ffmpeg and other commands, when it starts capturing frames from my web-cam,
  I am using following method for that.

  public class FFMPEGClass {
  
  
  
      private String ffmpegExeLocation, line;
  
      private final String FRAME_DIGITS = "010";
  
  
  
      public FFMPEGClass(String capturingDName, String outputImagesLocation, int framesPerSecond) {
  
          ffmpegExeLocation = System.getProperty("user.dir") + "\\bin\\";
  
          System.out.println(ffmpegExeLocation);
  
          try {            
  
              System.out.println(ffmpegExeLocation + "ffmpeg -t 100000 "
  
                      + "-f vfwcap -s 640x480 -i 0 -r 1/" + framesPerSecond + " -f image2 " + outputImagesLocation + "\\camera%"+FRAME_DIGITS+"d.jpg");
  
              Process pp = Runtime.getRuntime().exec(ffmpegExeLocation + "ffmpeg -t 100000 "
  
                      + "-f vfwcap -s 640x480 -i 0 -r 1/" + framesPerSecond + " -f image2 " + outputImagesLocation + "\\camera%"+FRAME_DIGITS+"d.jpg");
  
              BufferedReader br = new BufferedReader(new InputStreamReader(pp.getErrorStream()));
  
              while((line = br.readLine()) != null){
  
                   System.out.println(line);
  
              }
  
          } catch (Exception ex) {
  
              ex.printStackTrace();
  
          }
  
      }
  
  }

  In my case capturingDName is USB2.0 UVC VGA WebCam
  outputImagesLocation is e :\myfolder\frames and
  framesPerSecond is 10

  This code works well but it is unable to capture frames efficiently, In other words I want to say that its processing is very slow, can anyone please tell that how can I optimize it so that it can capture frames very fastly.

  I have Intel Core i3 processor with 6 GB of RAM

  I have already checked many answers from google and stackoverflow but these are not working in my case

• Different code(.java file) for different platform ?

  2 mars 2016, par AR792

  I have a code where image data is passed from bitmap to FFmpeg frame recorder and converted to a video. But i need to make small changes while running it on LG G3(armv7) from Asus zenfone 5(x86).

  Following are the class variables that create the issue :(declared under, class Main Activity)

  inputWidth = 1024 ;

  inputHeight = 650 ;

  Following is the method where the issue occurs :

   byte [] getNV21(int inputWidth, int inputHeight, Bitmap bitmap) {
  
  
  
      int [] argb = new int[inputWidth * inputHeight];
  
  
  
      bitmap.getPixels(argb, 0, inputWidth, 0, 0, inputWidth, inputHeight);
  
  
  
      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;
  
  
  
      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 ++;
  
          }
  
      }
  
  }

  Working CODE :

  LG G3 :I can use the above variables at any place in the code to get the required output.
  Bitmap size returned = 2734200

  Asus Zenfone 5 : Except at creating the bitmap, I have to use everywhere else bitmap.getHeight() and bitmap.getWidth(), to get the required output.

  Surprisingly here Bitmap size returned = 725760 (So its not setting according to set bitmap parameters ?)

  INCORRECT CODE :

  LG G3 : IF i use bitmap.getHeight() and bitmap.getWidth(), i get java.lang.ArrayIndexOutOfBoundsException : length = 102354 , index = 102354. @getNV21 method

  Asus Zenfone 5 : If i use inputWidth , inputHeight i get
  java.lang.IllegalArgumentException : x + width must be <= bitmap.width() @getNV21 method

  How can i generalize the above code for both phones ?