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• C# The specified executable is not a valid application for this OS platform

  22 avril 2015, par Mihai Ciully

  I’m making a Video sharing application(the likes of youtube) for my bachelor degree(the project is done in asp.net web forms)
  And i want to convert any video the user uploads to mp4.For this i’m using the Nreco ffmpeg wrapper for asp.

  I’m doing all this locally and this project is not going live.

  The video conversion is done in a separate thread.

  protected void Upload_Click(object sender, EventArgs e)
  
  {
  
  //File Uploads to Server
  
  Thread t1 = new Thread(
  
  unused => compressVideo(Video_Path, Final_Path,User_id)
  
  );
  
  t1.Start();
  
  }
  
  
  
  public static void compressVideo(string Video_Path, string Final_Path,string UID)
  
  {
  
      var ffMpeg = new NReco.VideoConverter.FFMpegConverter();
  
      ffMpeg2.ConvertProgress += (o, args) =>
  
          {
  
              //SignalR calls.Doing this to update the ui
  
          };
  
  
  
      ffMpeg.ConvertMedia(Video_Path, Final_Path, NReco.VideoConverter.Format.mp4);
  
  }

  First time i did this it all worked fine,not a single problem.
  Two weeks late,after not modifying this page,i try it again and the application throws this exception :

  An unhandled exception of type ’System.ComponentModel.Win32Exception’
  occurred in NReco.VideoConverter.dll

  Additional information : The specified executable is not a valid
  application for this OS platform.

  on the line :

  ffMpeg.ConvertMedia(Video_Path, Final_Path, NReco.VideoConverter.Format.mp4);

  If i call the ffMpeg.ConvertMedia(),the exception is not thrown and the code works as expected.So im guessing it has something to do with threads.But that’s not all.
  After messing around with the code trying to solve this and not succeeding i revert back to the original code.In a last attempt i try it again(with the original code) and the application gave the build error.

  attempted to access an unloaded appdomain.

  Any modification i did to the code was ignored and i was always getting that error when compiling.
  After taking a five minutes break to calm down, i try it again.It magically fixed its self.The build error was gone and even the conversion was working.

  But the dream didn’t last long.After a few minutes the conversion thread started throwing the same exception again.
  I was not able to replicate the same result.

  My experience and knowledge with asp.net web forms and web design in general are fairly low,so please keep the answers as simple as possible.

• FFMPEG waveform transparent, background solid color

  11 mai 2016, par user1152226

  I am trying to generate a waveform with ffmpeg, I want the background to be a solid color, and the actual waveform to be transparent. The following achieves partially what i want, except that in has a black background. I would like to be able to change this to any color, but have the waveform be transparent. How can i achieve this with ffmepg ?

  ffmpeg -i input.mp3 -filter_complex \
  
  "[0:a]aformat=channel_layouts=mono,\
  
  compand=gain=-6, \
  
  showwavespic=s=600x120, \
  
  colorchannelmixer=rr=1:gg=0:bb=0:aa=1,\
  
  drawbox=x=(iw-w)/2:y=(ih-h)/2:w=iw:h=1:color=red,\
  
  format=rgba,\
  
  colorkey=#ff0000" \
  
  -vframes 1 output.png

  This generates this waveform : the background is black, the waveform itself is transparent. How do I change the background color to a different color, while still keeping the waveform transparent ?

  

• Using ffmpeg shared library in a commercial C/C++ application

  9 mai 2017, par Peter

  We have a C++-based application that runs on Windows, Mac, and Linux. I now need to add h.264 and h.265 decoding within this application. It seems ffmpeg will do the trick.

  As ours is a commercial application, we cannot disclose the source code to public. However, as I understand, FFMpeg is based on LGPL licensing requirements. Going through various articles on LGPL requirements, it seems I can use ffmpeg without disclosing our source code as long as :

  1. I build ffmpeg as a shared libraries and make sure that I don’t use "—enable-gpl" flag during configuration.
  2. I acknowledge in our About dialog box that we are using ffmpeg shared libraries.

  Can someone please verify if this more or less meets the requirements ? Regards.

  Note that I need ffmpeg only to decode and not to encode. Therefore, I don’t have to use "—enable-libx264" and "—enable-libx265" flags.