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• Process is not exiting ffmpeg.exe only for the command which detects the silences from a video

  20 juillet 2015, par Jitender Kumar

  The job of the method ExecuteCommandSync is to detect the silences from a video and return the output as string but when I run this code it never bring the value of proc.HasExited as true. If I forcefully drag the debugger to the line

  result =proc.StandardOutput.ReadToEnd()

  then it never exit the ffmpeg.exe so as a result control never returns back.

  Although the same method is working fine for a different command like creating an audio file from a video. In this case proc.HasExited also returns false but it also generates the audio file successfully.

  public static string ExecuteCommandSync(string fileName, int timeoutMilliseconds)
  
      {
  
          string result = String.Empty;
  
          string workingDirectory = Directory.GetCurrentDirectory();
  
          try
  
          {
  
              string command = string.Format("ffmpeg -i {0} -af silencedetect=noise=-20dB:d=0.2 -f null -", "\"" + fileName + "\"");                
  
              System.Diagnostics.ProcessStartInfo procStartInfo =
  
                  new System.Diagnostics.ProcessStartInfo("cmd", "/c " + command);
  
  
  
              procStartInfo.WorkingDirectory = workingDirectory;                
  
              procStartInfo.RedirectStandardOutput = true;
  
              procStartInfo.RedirectStandardError = true;
  
              procStartInfo.UseShellExecute = false;                
  
              procStartInfo.CreateNoWindow = false;                
  
              System.Diagnostics.Process proc = new System.Diagnostics.Process();
  
              proc.StartInfo = procStartInfo;
  
              proc.Start();                
  
              proc.WaitForExit(timeoutMilliseconds);
  
              // Get the output into a string 
  
              if (proc.HasExited)
  
              {
  
                  if (!proc.StandardOutput.EndOfStream)
  
                  {
  
                      result = proc.StandardOutput.ReadToEnd();
  
                  }
  
                  else if (!proc.StandardError.EndOfStream)
  
                  {
  
                      result = "Error:: " + proc.StandardError.ReadToEnd();
  
                  }
  
              }
  
          }
  
          catch (Exception)
  
          {
  
              throw;
  
          }
  
          return result;
  
      }

  So please advice.

• Capture still image from remote ip cam using avconv

  12 août 2015, par Stevanicus

  I’m attempting to capture a single still from an ip camera with avconv in ubuntu (server).

  Can only tell me what’s wrong with the following command :

  avconv -i rtsp://[USER]:[PASS]@[IPADDRESS]:554/11 -s 1920x1080 -f image2 foo.jpg

  The error message I’m getting at the moment is :

  [rtsp @ 0xb938e0] Could not find codec parameters (Video: h264, 1920x1080)
  
  [rtsp @ 0xb938e0] Estimating duration from bitrate, this may be inaccurate
  
  Guessed Channel Layout for  Input Stream #0.1 : mono
  
  Input #0, rtsp, from 'rtsp://xxx:xxx@xxx.xxx.xxx.xxx:554/11':
  
    Metadata:
  
      title           : rtsp session
  
    Duration: N/A, bitrate: N/A
  
      Stream #0.0: Video: h264, 1920x1080, 90k tbn
  
      Stream #0.1: Audio: pcm_alaw, 8000 Hz, mono, s16, 64 kb/s
  
  [buffer @ 0xb98520] Invalid pixel format string '-1'
  
  Error opening filters!

  In case it’s of any value, I’m using a 2.0 MB IP Camera from Sinocam. I am able to view a live stream from the camera remoting using iSpy - however, I just can’t create an image still from it.

  Thank you.

• FFMPEG RTP UBUNTU NETWORK issue

  14 août 2015, par Иван Колесников

  I’m want to copy a bunch of SD sources from mpegts transported with RTP on local files. (VBR mpeg2video, mp2 audio). It works fine for one multicast source with following command : ffmpeg -i rtp ://@IP1:PORT -c copy video1.mpg. But when I run a second ffmpeg instance with following command :
  ffmpeg -i rtp ://@IP2:PORT -c copy video2.mpg then I’m start to getting errors from both ffmpeg instance ("RTP : dropping old packet received too late") and in both files (video1.mpg and video2.mpg) start to recording video from second source (rtp ://@IP2:PORT). This issue is only under Linux (Ubuntu 15.04). I have no problems under Windows and when try the same actions from files to files. Under Ubuntu even two ffplay instances tuned to different sources play back the same content (from source which was opened second). I tried playing back with vlc and there is no such problem.
  I can resolve this issue when using ffmpeg with -f key : ffmpeg -f mpegts -i rtp ://@IP1:PORT -c copy video1.mpg and ffmpeg -f mpegts -i rtp ://@IP2:PORT -c copy video2.mpg, but then I getting following errors : "[mpegts @ 0x306e240] PES packet size mismatch" and receive both files (video1.mpg and video2.mpg) with artifacts and freeze effects. This issue appears for both operation systems. How can I recording video from few RTP streams contemporaneously under Ubuntu without errors and artifacts ? Please give advice.