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• ffmpeg - Incompatible sample format '(null)'

  17 juin 2012, par abrahab

  I convert videos from different sources with ffmpeg to mp4 with libx264 codec. After conversation time to time I got incorrect format error when trying to load already converted video with ffmpeg : Incompatible sample format '(null)' for codec 'aac', auto-selecting format 's16'

  Seems, it is audio stream problem with aac codec ? How to fix or how to convert videos to mp4 to be sure that I will not get the following error ? Maybe somehow need to specify audio format at the ffmpeg convert command ?

  ps. Video must work at Iphone/Ipad.
  pps. the main problem, that such videos with the following error can not be pseudo-streamed with nginx (got 500 Error)
  ppps. and sorry for my bad english, please, correct my text if need. thanks.

  Some additional info from file :

    Duration: 00:00:10.30, start: 0.000000, bitrate: 614 kb/s
  
      Stream #0.0(rus): Video: h264 (High), yuv420p, 1024x576, 567 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00
  
      Stream #0.1(rus): Audio: aac, 22050 Hz, stereo, s16, 57 kb/s
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00

• Trying to redirect binary stdout of ffmpeg to NeroAacEnc stdin

  2 mai 2017, par Ben

  I am trying to write a program in C# 2010 that converts mp3 files to an audio book in m4a format via ffmpeg.exe and NeroAACenc.exe.
  For doing so I redirect stdout of ffmpeg to stdin of the Nero encoder within my application using the build in Diagnostics.Process class.

  Everything seems to work as expected but for some reason StandardOutput.BaseStream
  of ffmpeg stops receiving data at some time. The process does not exit and the ErrorDataReceived event is also not getting raised.
  The produced output m4a file has always a length of 2 minutes. The same applies if I just encode the mp3 file to a temp wav file without feeding Nero.

  I tried the same via the command line and this works without any problem.

  ffmpeg -i test.mp3 -f wav - | neroAacEnc -ignorelength -if - -of test.m4a 

  Can anyone please tell me what I am doing wrong here ?
  Thanks in advance.

  class Encoder
  
  {
  
      private byte[] ReadBuffer = new byte[4096];
  
      private Process ffMpegDecoder = new Process();
  
      private Process NeroEncoder = new Process();
  
      private BinaryWriter NeroInput;
  
  
  
      //Create WAV temp file for testing
  
      private Stream s = new FileStream("D:\\test\\test.wav", FileMode.Create);
  
      private BinaryWriter outfile;
  
  
  
      public void Encode()
  
      {
  
          ProcessStartInfo ffMpegPSI = new ProcessStartInfo("ffmpeg.exe", "-i D:\\test\\test.mp3 -f wav -");
  
          ffMpegPSI.UseShellExecute = false;
  
          ffMpegPSI.CreateNoWindow = true;
  
          ffMpegPSI.RedirectStandardOutput = true;
  
          ffMpegPSI.RedirectStandardError = true;
  
          ffMpegDecoder.StartInfo = ffMpegPSI;
  
  
  
          ProcessStartInfo NeroPSI = new ProcessStartInfo("neroAacEnc.exe", "-if - -ignorelength -of D:\\test\\test.m4a");
  
          NeroPSI.UseShellExecute = false;
  
          NeroPSI.CreateNoWindow = true;
  
          NeroPSI.RedirectStandardInput = true;
  
          NeroPSI.RedirectStandardError = true;
  
          NeroEncoder.StartInfo = NeroPSI;
  
  
  
          ffMpegDecoder.Exited += new EventHandler(ffMpegDecoder_Exited);
  
          ffMpegDecoder.ErrorDataReceived += new DataReceivedEventHandler(ffMpegDecoder_ErrorDataReceived);
  
          ffMpegDecoder.Start();
  
  
  
          NeroEncoder.Start();
  
          NeroInput = new BinaryWriter(NeroEncoder.StandardInput.BaseStream);
  
  
  
          outfile = new BinaryWriter(s);
  
  
  
          ffMpegDecoder.StandardOutput.BaseStream.BeginRead(ReadBuffer, 0, ReadBuffer.Length, new AsyncCallback(ReadCallBack), null);
  
  
  
      }
  
  
  
      private void ReadCallBack(IAsyncResult asyncResult)
  
      {
  
          int read = ffMpegDecoder.StandardOutput.BaseStream.EndRead(asyncResult);
  
          if (read > 0)
  
          {
  
  
  
              NeroInput.Write(ReadBuffer);
  
              NeroInput.Flush();
  
  
  
              outfile.Write(ReadBuffer);
  
              outfile.Flush();
  
  
  
              ffMpegDecoder.StandardOutput.BaseStream.Flush();
  
  
  
              ffMpegDecoder.StandardOutput.BaseStream.BeginRead(ReadBuffer, 0, ReadBuffer.Length, new AsyncCallback(ReadCallBack), null);
  
          }
  
          else
  
          {
  
              ffMpegDecoder.StandardOutput.BaseStream.Close();
  
              outfile.Close();
  
          }
  
  
  
      }
  
  
  
      private void ffMpegDecoder_Exited(object sender, System.EventArgs e)
  
      {
  
          Console.WriteLine("Exit");
  
      }
  
  
  
      private void ffMpegDecoder_ErrorDataReceived(object sender, DataReceivedEventArgs errLine)
  
      {
  
          Console.WriteLine("Error");
  
      }
  
  
  
  }

• Convert image to black and white with ffmpeg

  20 septembre 2023, par maddogandnoriko

  How can I convert an image to b&w with ffmpeg ?

  


  I am making some coloring book images by decoloring images and reducing to a black outline. Even though they appear b&w most are not.