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• Different results for exit conditions in process call

  31 août 2017, par Martin KS

  As a small part of a project, I’m calling ffmpeg to convert a video - I worked from an old example that used some of the output to create a progress bar, which was hanging. Code below :

  [initiation code common to both examples]
  
      Dim inputFile, outputFile As String, myProcess As New Process
  
      Dim psiProcInfo As New ProcessStartInfo, ffreader As StreamReader
  
  
  
  
  
      inputFile = "C:\Users\mklefass\Downloads\Video 2017-08-16 21.01.39.mov"
  
      outputFile = "C:\Users\mklefass\Downloads\tmp2\Output"
  
  
  
      psiProcInfo.FileName = Application.StartupPath + "\ffmpeg.exe"  'Location Of FFMPEG.EXE
  
      psiProcInfo.Arguments = " -i " & Chr(34) & inputFile & Chr(34) & " -vf fps=5 " & Chr(34) & outputFile & "%d.jpg" & Chr(34)                              'start ffmpeg with command strFFCMD string
  
      psiProcInfo.UseShellExecute = False                             'use the shell execute command we always want no
  
      psiProcInfo.WindowStyle = ProcessWindowStyle.Hidden             'hide the ffmpeg process window
  
      psiProcInfo.RedirectStandardError = True                        'Redirect the error out so we can read it
  
      psiProcInfo.RedirectStandardOutput = True                       'Redirect the standard out so we can read it
  
      psiProcInfo.CreateNoWindow = True
  
  
  
  [bit that changes]
  
  myProcess.Start()
  
  ffreader = myProcess.StandardError
  
  Do
  
      Try
  
          If Not myProcess.HasExited Then
  
              'Debug.WriteLine(ffreader.ReadLine)
  
          End If
  
      Catch
  
          If Not myProcess.HasExited Then
  
              MsgBox("Something went wrong")
  
          End If
  
      End Try
  
  Loop Until myProcess.HasExited
  
  MsgBox("done")

  I then found another example that just called the executable and then continued when it was done - as below :

  [same initialisation]
  
  Debug.WriteLine("Starting...")
  
  myProcess.Start()
  
  strOutput = myProcess.StandardError.ReadToEnd
  
  myProcess.WaitForExit()
  
  myProcess.Close()
  
  
  
  Debug.Write(strOutput)
  
  MsgBox("done")

  The second approach worked perfectly... What’s different about the "exit state" that Process.HasExited and Process.WaitForExit look for ?

• FFMPEG- force abortion on certain conditions

  18 juin 2023, par POL

  FFMPEG shows various errors, once in a while, during which the video is stuck or choppy. I couldn't find a way to fix it, but I figured that if I start the process again, it gets fixed.
The errors are like :
timestamp discontinuity for stream
New video stream with index 6

  


  This is what I run :

  


  ffmpeg -xerror -abort_on empty_output_stream+empty_output -fflags +discardcorrupt -http_persistent false -i URL -c:v libx264 -c:a aac -preset superfast -copyts -f mpegts udp://localhost:1937?pkt_size=1316


  


  How can I force FFMPEG to abort ?

  


• If conditions in a loop breaking ffmpeg zoom command

  6 mai 2017, par Sulli

  I have built a bash script where I am trying to zoom in an image with ffmpeg, for 10s :

  ffmpeg -r 25 -i image0.jpg -filter_complex "scale=-2:10*ih,zoompan=z='min(zoom+0.0015,1.5)':d=250:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)',scale=-2:720"  -y -shortest -c:v libx264 -pix_fmt yuv420p temp_1.mp4 

  This command is included in a while loop, with two "if" conditions at the beginning of the loop :

  first=1017 
  
  i=0
  
  while read status author mySource myFormat urlIllustration credit shot_id originalShot categories title_EN length_title_EN text_EN tags_EN title_FR length_title_FR text_FR tags_FR title_BR length_title_BR text_BR tags_BR; do
  
  
  
      if [ $myFormat != "diaporama" ]; then 
  
          let "i = i + 1"
  
          continue
  
      fi
  
  
  
      if [ "$shot_id" -lt "$first" ]; then 
  
          let "i = i + 1"
  
          continue
  
      fi
  
  
  
      rm temp_1.mp4
  
      ffmpeg -r 25 -i image0.jpg -filter_complex "scale=-2:10*ih,zoompan=z='min(zoom+0.0015,1.5)':d=250:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)',scale=-2:720"  -y -shortest -c:v libx264 -pix_fmt yuv420p temp_1.mp4 
  
  
  
  
  
      let "i = i + 1"
  
  done <../data.tsv
  
  echo "All done."

  (I have removed stuff in the loop, this is the minimal code that is able to capture the problem).

  Now the weird bug : if I run this code like that, the video I am trying to generate will not be 10s long, only 1-2s long. ffmpeg exits with error "[out_0_0 @ 0x2fa4c00] 100 buffers queued in out_0_0, something may be wrong."

  Now if I remove one of the "if" conditions at the beginning of my loop (the first or the second, it doesn’t matter), the video will be generated fine and be 10s long.

  What could be the cause of this problem ?