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• Why do I get different codecs on Windows and Linux with same code ?

  27 janvier 2016, par user3277340

  I am using the API version of FFMPEG to generate a MP4 file from a series of images. I specify the output by calling

  AVFormatContext *oc = NULL ;
  avformat_alloc_output_context2 (&oc,NULL,"mp4",NULL) ;

  Running the exact same code on Windows and Linux I get different codecs assigned. On Windows, the value of oc->oformat->video_code is AV_CODEC_ID_H264 (28), but on Linux I get AV_CODEC_ID_MPEG4.

  I tracked this down because on Windows my calls to avcodec_encode_video2(.,.,.,&got_packet) were always returning got_packet=0 so I never called av_interleaved_write_frame. I added a NULL AVFrame at the end to flush the video. But it was very small and did not contain the images I expected to see there.

  But on Linux everything worked just fine. So I went ahead and manually changed the value of oc->oformat->video_code and I got the expected results.

  My questions :

  1) Why do I get different codec types on different platforms with the same code ? Is there a parameter I need to set to force MPEG4 ?

  2) Is it "legal" to change this parameter after the call to avformat_alloc_output_context2 ? My concern is that "oc" has been properly initialized and, with the change, something may be inconsistent.

  3) Is there a way to force the MPEG4 codec on any machine ?

  Thanks.

• avdevice/decklink : Add missing libraries when building with DeckLink support on Windows.

  18 juillet 2015, par Chris Spencer

  avdevice/decklink : Add missing libraries when building with DeckLink support on Windows.
  Signed-off-by : Chris Spencer <spencercw@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] configure

• Calling external applications from windows service [duplicate]

  3 novembre 2016, par vvj

  This question already has an answer here :

  • How can I run an EXE program from a Windows Service using C# ?
    
    5 answers
    

  I have a windows service as part of my project which has to communicate with external applications to process the files. One of the external application I am using is FFMPEG.exe.

  My problem is when I call FFmpeg or other applications as the new process. After starting the process, it is getting idle. it will neither get execute successfully nor get an exit.

  I am facing this problem with multiple external exe’s and it happens only while calling from the windows service. When I tried the same block of code from a windows forms application, it works perfectly. Below is the sample code I used. Could anyone tell me whats wrong with this.?

  Process FFMPEGProcess = new Process();
  
  FFMPEGProcess.StartInfo.FileName =@"ffmpeg.exe";                                   
  
  string strArgument = @" -i  \\MachineName\video\file.mp4 -y -s 176x132 -r 0.2 \\MachineName\Image\File%4d.jpg";
  
  FFMPEGProcess.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
  
  FFMPEGProcess.StartInfo.CreateNoWindow = true;
  
  FFMPEGProcess.StartInfo.UseShellExecute = true;
  
  FFMPEGProcess.StartInfo.Arguments = strArgument;
  
  FFMPEGProcess.Start();            
  
  FFMPEGProcess.WaitForExit();