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• avpacket : Deprecate av_dup_packet

  23 octobre 2015, par Luca Barbato

  avpacket : Deprecate av_dup_packet
  As documented, `av_dup_packet` is broken by design, `av_packet_ref`
  
  matches the AVFrame ref-counted API and can be safely used instead.
  

  • [DBH] doc/APIchanges
  • [DBH] libavcodec/avcodec.h
  • [DBH] libavcodec/avpacket.c
  • [DBH] libavformat/matroskaenc.c
  • [DBH] libavformat/mux.c

• Compiling ffmpeg to support libx264 encoder

  18 octobre 2016, par Nooruddin Lakhani

  I am using ffmpeg library for video compression. I am using the sample code from ffmpeg4android_lib and the following command to compress the video.

  String[] complexCommand = new String[]{ "ffmpeg", "-y", "-i",
  
              "/sdcard/videokit/in.mp4", "-strict", "experimental",
  
              "-vcodec", "mpeg4", "-b:v", "500k",
  
              "-acodec", "aac", "-ar", "48000", "-ac", "1",
  
              "-b:a", "96k", "-s", "480x360", "/sdcard/videokit/out.mp4" };

  in.mp4 video file is recorded from camera which is originally 46 mb. It convert video file size to 1.7 mb with better quality. When I select another video from Whatsapp Gallery which is already compressed by Whatsapp like I have a Whatsapp video which is 6 min duration and 9.8 mb in size, when I select this video to compress with the same command, It’s size becomes 26 mb which is larger than original. When I decrease the video bit rate from 500k to 150k then output file size becomes smaller but quality becomes poor which cannot be acceptable.

  I have found people are using libx264 encoder to find better quality with minimum file size. I have changed my compress command to use this encoder.

  String[] complexCommand = new String[]{ "ffmpeg", "-y", "-i",
  
          "/sdcard/videokit/in.mp4", "-strict", "experimental",
  
              "-vcodec", "libx264", "-preset", "medium", "-b:v", "500k",
  
              "-crf", "26", "-acodec", "aac", "-ar", "48000", "-ac", "1",
  
              "-b:a", "96k", "-s", "480x360", "/sdcard/videokit/out.mp4" };

  But the above command is not working with ffmpeg library. I am getting the following issue which write log in vk.log file

  Reading option '-vcodec' ... matched as option 'vcodec' (force video codec ('copy' to copy stream)) with argument 'libx264'.
  
  Reading option '-preset' ...Unrecognized option 'preset'.
  
  Error splitting the argument list: Option not found
  
  ffmpeg4android: ffmpeg_parse_options not passed
  
  exit_program: 1

  I am trying to use the encoder libx264, but ffmpeg not compiled to support this encoder. How can I configure libx264 with ffmpeg ? I have found the following references to configure ffmpeg With libx264

  1- ffmpeg on Heroku : unrecognized option ’preset’

  2- http://blog.oneiroi.co.uk/linux/ffmpeg-install-with-libx264-h264/

  3- http://writingminds.github.io/ffmpeg-android/

  Should I have to download NDK and will have to configure It through libx264 commands as defined in above references. I am not getting how to configure it through commands because I have to configure it in Android Studio with ffmpeg and I am using windows not ubuntu or Linux. Please suggest me how can i achieve this ?

• 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.