Recherche avancée

Sur d’autres sites (13162)

• Mavericks OpenCV 2.4.9 videoWriter doesn't work

  29 septembre 2014, par Maggick

  I’m having issues writing out video files using OpenCV on Mac.

  I’m running Mavericks and have OpenCV 2.4.9 and FFMPEG 2.4.1 installed, and the newest x264 from videolan.

  But when I run even the example code from opencv website I still am not able to produce a video. http://docs.opencv.org/doc/tutorials/highgui/video-write/video-write.html

  When I run the example code I get a blank video file.

  So my code doesn’t seem to be the problem. And I don’t get any errors so I am assuming the problem is with the codec not working. But I don’t understand what I am missing.

  Has anyone else had a similar problem ? Since I’m using a Mac I cannot use the -1 flag to pick a codec.

• Can somebody say why that doesn't work

  6 août 2018, par atif sesu

  I want to convert webm to mp4.

  private String ffmpegApp;
  
  
  
  public FLVConverter(String ffmpegApp) {
  
      this.ffmpegApp = ffmpegApp;
  
  }
  
  
  
  public void convert(String filenameIn, String filenameOut, int width, int height) throws IOException, InterruptedException {
  
      convert(filenameIn, filenameOut, width, height, -1);
  
  }
  
  
  
  public int convert(String filenameIn, String filenameOut, int width, int height, int quality)
  
          throws IOException, InterruptedException {
  
      ProcessBuilder processBuilder;
  
      if (quality > -1) {
  
          processBuilder = new ProcessBuilder(ffmpegApp, "-i", filenameIn, "-ar", "44100",
  
                  "-s", width + "*" + height, "-qscale", quality + "", filenameOut);
  
      } else {
  
          processBuilder = new ProcessBuilder(ffmpegApp, "-i", filenameIn, "-ar", "44100",
  
                  "-s", width + "*" + height, filenameOut);
  
      }
  
  
  
      Process process = processBuilder.start();
  
  
  
      InputStream stderr = process.getErrorStream();
  
      InputStreamReader isr = new InputStreamReader(stderr);
  
      BufferedReader br = new BufferedReader(isr);
  
      String line;
  
      while ((line = br.readLine()) != null) ;
  
  
  
      {
  
      }
  
  
  
      return process.waitFor();
  
  }
  
  
  
  public static void main(String[] args) throws Exception {
  
      FLVConverter FLVConverter = new FLVConverter("C:\\Users\\Casper\\Desktop\\ffmpeg\\bin\\ffmpeg.exe");
  
      FLVConverter.convert("C:\\Users\\Casper\\Desktop\\videoplayback.webm",
  
              "C:\\Users\\Casper\\Desktop\\a.mp4", 300, 200, 5);
  
  }

• ffmpeg - how does moving overlay / text command work ?

  7 mars 2015, par Stpn

  In Ffmpeg you can create moving text :

  ffmpeg -y -t 10 -s qcif -f rawvideo -pix_fmt rgb24 -s 1280x720 -i /dev/zero -g 1 -r 24 -vf drawtext="fontfile=~/fonts/Trebuchet_MS.ttf:text='thing crawls':fontsize=155:fontcolor=red:y=h-20*t" wow.mpg

  So this will give me a black frame with "thing crawls" slowly going from bottom up..

  If I know the length of the video (20 seconds) and want to, for example create "thing falls" that starts at the top of the screen at time 0 and goes to the bottom of the screen until 00:00:20, how do I do that ?

  Also can I create the situation where the text will start going from top to bottom, but stop at the middle of the screen ?