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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 ?

• frame_thread_encoder : make 'exit' member atomic.

  11 septembre 2017, par Ronald S. Bultje

  frame_thread_encoder : make 'exit' member atomic.
  Should fix the following tsan warning :
  WARNING : ThreadSanitizer : data race (pid=19806)
  
    Read of size 4 at 0x7b84000012f0 by thread T9 :
  
      #0 worker src/libavcodec/frame_thread_encoder.c:66 (ffmpeg+0x0000007f349e)
  
  [..]
  
    Previous write of size 4 at 0x7b84000012f0 by main thread (mutexes : write M1395) :
  
      #0 ff_frame_thread_encoder_free src/libavcodec/frame_thread_encoder.c:239 (ffmpeg+0x0000007f379e)
  
  [..]
  

  • [DH] libavcodec/frame_thread_encoder.c

• Why am I getting an exit status of 1 ?

  24 mai 2018, par Akaisteph7

  So, I am writing this code to analyze this video but I am facing this issue when I try to run it in Spyder, Anaconda :

  import subprocess
  
  from subprocess import call
  
  import math
  
  
  
  ##Converts the given file into a series of images
  
  def Video_to_Image_Converter(fileName):
  
      res1 = call("ffmpeg -i " + fileName + " -vf fps=1 frame-%d.jpg", shell=True)
  
      print(res1)
  
      result = subprocess.Popen('ffprobe -i '+ fileName +' -show_entries format=duration -v quiet -of csv="p=0"', stdout=subprocess.PIPE,stderr=subprocess.STDOUT, shell=True)
  
      output = result.communicate()
  
      print(output)
  
      #return math.ceil(float(output[0])) + 1
  
  
  
  
  
  if __name__ == '__main__':
  
      videoLength = Video_to_Image_Converter('sampleVideo.wmv')
  
      print(videoLength)

  So, this code worked fine in iPython but I started having issues when trying to use Spyder. res1 should have an exit status of 0 if everything went well but it is 1. However, I do not know what went wrong. All it says when running subprocess.check_output on call is :

  Command 'ffmpeg -i sampleVideo.wmv -vf fps=1 frame-%d.jpg' returned non-zero exit status 1

  Please help.