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• ffmpeg background worker runs in debug but not in application

  2 novembre 2019, par Purgitoria

  My application has a function of taking captured images and using an FFmpeg background worker to stitch these into a time-lapse video. The GUI has some simple options for video quality and for the source folder and output file. I had an older version of my application written in VB.NET and that worked without issue but I am rewriting in C# as it supports additional capture and filter capability in the image processing but am having real trouble figuring out what is wrong with this function.

  I have tried relocating FFmpeg to different locations just in case it was a permissions issue but that had no effect and I also tried to put the function in a "try" with a message box to output any exceptions but I got different errors that prevented me from compiling the code. When I run the application from within VS 2015 in the debugging tool the function works just fine and it will create a video from a collection of still images but when I build and install the application it does not work at all and I cannot see what is causing it to fail. In the options for ffmpeg I used the -report to output a log of what happens in the background worker and in debug, it creates this log but from the application, it does not so I presume it is not even running ffmpeg and going straight to the completed stage of the function.

  Function startConversion()
  
  
  
      CheckForIllegalCrossThreadCalls = False
  
      Dim quality As Integer = trbQuality.Value
  
      Dim input As String = tbFolderOpen.Text
  
      Dim output As String = tbFolderSave.Text
  
      Dim exepath As String = Application.StartupPath + "\\bin\ffmpeg.exe"
  
      input = input & "\SCAImg_%1d.bmp"
  
      input = Chr(34) & input & Chr(34)
  
      output = Chr(34) & output & Chr(34)
  
  
  
      Dim sr As StreamReader
  
      Dim ffmpegOutput As String
  
  
  
      ' all parameters required to run the process
  
      proc.StartInfo.UseShellExecute = False
  
      proc.StartInfo.CreateNoWindow = True
  
      proc.StartInfo.RedirectStandardError = True
  
      proc.StartInfo.FileName = exepath
  
      proc.StartInfo.Arguments = "-framerate 25 -start_number 0 -pattern_type sequence -framerate 10 -i " & input & " -r 10 -c:v libx264 -preset slow -crf " & quality & " " & output
  
      proc.Start()
  
  
  
      lblInfo.Text = "Conversion in progress... Please wait..."
  
      sr = proc.StandardError 'standard error is used by ffmpeg
  
      btnMakeVideo.Enabled = False
  
      Do
  
          ffmpegOutput = sr.ReadLine
  
          tbProgress.Text = ffmpegOutput
  
      Loop Until proc.HasExited And ffmpegOutput = Nothing Or ffmpegOutput = ""
  
  
  
      tbProgress.Text = "Finished !"
  
      lblInfo.Text = "Completed!"
  
      MsgBox("Completed!", MsgBoxStyle.Exclamation)
  
      btnMakeVideo.Enabled = True
  
      Return 0
  
  
  
  End Function

  I checked the application folder and it does contain a subfolder \bin withe the ffmpeg.exe located within the folder so I then used cmd to run an instance of the installed ffmpeg from the application folder and it seemed to be throwing out permissions errors :

  Failed to open report "ffmpeg-20191101-191452.log" : Permission denied
  Failed to set value ’1’ for option ’report’ : Permission denied
  Error parsing global options : Permission denied

  This seems then like it is certainly a permissions problem but where I am not sure. I did not run into this error when using VB.NET so I am wondering where I am going wrong now. I thought perhaps it would just be a write permission in the application folder so I the removed the -report and ran ffmpeg again using cmd from my application folder and it then gave the error

  C :\Users\CEAstro\Pictures\AnytimeCap : Permission denied

  Am I missing something really obvious in my code or is there something more fundamental I have wrong in my setup ?

  I should also add that I tried running ffmpeg via cmd from a copy that was manually placed elsewhere (i used the same file) and that actually worked. For some reason, it seems like it just will not work from wherever my application installs it.

• How can I bundle ffmpeg in an Electron application

  14 janvier 2024, par jshbrntt

  I'm building an Electron application starting from the electron-webpack boilerplate.

  



  I found this node module @ffmpeg-installer/ffmpeg which installs a compatible precompiled binary into the /node_modules directory then makes the path of that executable accessible through.

  



  const ffmpegPath = require('@ffmpeg-installer/ffmpeg').path


  



  This works fine during development, but when I build the distributable and run it I get an error when attempting to spawn a child process with that path. Presumably, because the path does not point at the binary.

  



  The path is set to the following when running the distributable.

  



  /Users/me/project/dist/mac/AppName.app/Contents/Resources/app.asar/node_modules/@ffmpeg-installer/darwin-x64/ffmpeg


  



  However, when looking in the AppName.app package contents I find the binary in the following path.

  



  /Users/me/project/dist/mac/AppName.app/Contents/Resources/app.asar.unpacked/node_modules/@ffmpeg-installer/darwin-x64/ffmpeg


  



  How should I include binary dependencies in an Electron application using electron-webpack and electron-builder ?

  


• OpenCV IP camera application crashes [h264 @ 0xxxxx] missing picture in access unit

  9 novembre 2016, par tod

  I have an opencv application in cpp.

  It captures video stream and saves it to video files with the simple constructs from opencv.

  It works perfectly with my webcam.

  But, it crashes maybe after about ten seconds, while I run it to capture the stream from IP Camara.

  My compile command is :

  g++ -O3 IP_Camera_linux.cpp -o IP_Camera `pkg-config --cflags --libs opencv`

  My Stream from IP cam is accessed like this :

  const string Stream = "rtsp://admin:xxxx@192.168.0.101/";

  It does run perfectly, shows video and saves it until the displayed video freezes and the application crashes. While the error message on the terminal is :

  [h264 @ 0x15e6f60] error while decoding MB 59 31, bytestream (-20)
  
  [h264 @ 0x15e8200] error while decoding MB 61 27, bytestream (-3)
  
  [h264 @ 0x109c880] missing picture in access unit
  
  [h264 @ 0x109c000] no frame!

  To my understanding, the fist two lines in the above error message might have something to do but does not actually crash the application. The last two lines are probably the reasons or the cause ?

  Any help ?