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• Java FFmpeg no output

  31 décembre 2018, par Games9999

  I´ve run into problem. I want to convert video using ffmpeg but it gives me no output

  public void convert(String inputFile, String outputFile, String ... optionalParams) {
  
      ProcessBuilder processBuilder = new ProcessBuilder("ffmpeg", "-i", "\"" + inputFile.trim() +"\"", "\""+ outputFile.trim() + "\"");
  
      DownloadRecord downloadRecord = table.getItems().get(0);
  
      downloadRecord.setStatus("Downloading");
  
         // Try to execute process
  
         try {
  
             // Set the working directory
  
             processBuilder.directory(new File(workingDirectory));
  
             //Start the process
  
             Process process = processBuilder.start();
  
  
  
             // Read the output from cmd
  
             BufferedReader r = new BufferedReader(new InputStreamReader(process.getInputStream()));
  
             BufferedReader ra = new BufferedReader(new InputStreamReader(process.getErrorStream()));
  
  
  
             String line;
  
             String errline;
  
             while ((line = r.readLine()) != null) {
  
                  System.out.println(line);
  
             }
  
  
  
             while ((errline = ra.readLine()) != null) {
  
                  System.out.println(errline);
  
             }
  
             process.waitFor();
  
             System.out.println("the end");
  
         } catch(IOException | InterruptedException e) {
  
             System.out.println(e.toString());
  
         }
  
  }

  I’ve been searching on stackoverflow and find some solutions, none worked. What I tried and figured out so far

  • No output or error output
  • I tried to remove backslashes from ProcessBuilder, it
    also gives me no output
  • I tried to let the program running, but it never finishes
  • I tried to use full path to the ffmpeg, no changes
  • I tried to run the video, no error
  • I am using
    Netbeans IDE so I tried clean and rebuild project, no change
  • process also never finishes

  I would like from it an output. Does someone know what I am doing wrong here ?

• Video capture from uncompressed AVI file

  16 décembre 2018, par quantum_well

  I am trying to use opencv (v3.4) to capture video frames from AVI file.
  This is my sample code.

  #include <iostream>
  
  #include <opencv2></opencv2>opencv.hpp>
  
  
  
  int main(int argc, char* argv[])
  
  {
  
      cv::VideoCapture cap;
  
      cap.open(argv[1]);
  
      if (!cap.isOpened())
  
      {
  
          std::cout &lt;&lt; "Failed to open video file\n";
  
          return 1;
  
      }
  
  
  
      cv::namedWindow( "1", cv::WINDOW_AUTOSIZE );
  
  
  
      int counter = 0;
  
      while (true)
  
      {
  
          cv::Mat frame;
  
          cap >> frame;
  
          if (frame.empty())
  
          {
  
              break;
  
          }
  
          std::cout &lt;&lt; counter++ &lt;&lt; " : "
  
              &lt;&lt; frame.cols &lt;&lt; " x " &lt;&lt; frame.rows &lt;&lt; std::endl;
  
  
  
          cv::imshow( "1", frame );
  
          cv::waitKey(30);
  
      }
  
  
  
      return 0;
  
  }
  
  </iostream>

  I have 2 types of files (according to media info from VLC) "8 bits greyscale (GREY)" and "Palettized RGB with palette elements R:G:B (RGBP)".

  Both types are played with VLC 2.2.8 (on Windows) just fine, but VLC 3.0.0 and newer versions can’t play 8-bit GREY videos. It seemed to me that the problem is caused by ffmpeg and the fix is to rebuild "opencv_ffmpeg_xxx.dll" file with an appropriate version of ffmpeg. I tried various version of ffplay from Zeroane builds and non can play 8-bit GREY videos (all frames are black).

  When used with 8-bit GREY video file the above sample code displays black screen, but frame size and frame counter are correct.

• iOS : FFMPEG Video stream to server gives 'Protocol not found' for RTSP

  13 janvier 2020, par John Lanzivision

  I have a demo iOS (8.0 min) project which streams a local mp4 to a server using FFMPEG. An RTMP destination works, an RTSP does not.

  When attempting to use RTSP I get a ’Protocol not found’ error from

  ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);

  I have tried to rebuild my FFMPEG libraries and ensured I have the necessary protocols included
  (To my understanding RTSP is a muxer in FFMPEG, hence the muxer enabling)

  --enable-muxer=rtsp \
  
  --enable-muxer=rtp \
  
  --enable-protocol=rtp \
  
  --enable-protocol=rtsp \

  In the code, I’ve tried to add the appropriate AVOptions

  av_dict_set(&opt, "rtsp_transport", "udp", 0);
  
  av_dict_set(&opt, "announce_port", "1935", 0);
  
  av_dict_set(&opt, "enable-protocol", "rtsp", 0);
  
  av_dict_set(&opt, "protocol_whitelist","file,udp,tcp,rtp,rtsp", 0);
  
  av_dict_set(&opt, "enable-protocol", "rtp", 0);
  
  av_dict_set(&opt, "enable-protocol", "rtsp", 0);
  
  av_dict_set(&opt, "enable-protocol", "udp", 0);
  
  av_dict_set(&opt, "enable-muxer", "rtsp", 0);
  
  av_dict_set(&opt, "enable-muxer", "rtp", 0);

  This is called in my open codec calls.

  ret = avcodec_open2(c, codec, &opt);

  It feels like I’m missing something very basic, any help would be amazing !