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• 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");
  
      }
  
  
  
  }

• Re-sampling H264 video to reduce frame rate while maintaining high image quality

  31 mars 2016, par BrianTheLion

  Here’s the mplayer output for a video of interest :

  br@carina:/tmp$ mplayer foo.mov 
  
  mplayer: Symbol `ff_codec_bmp_tags' has different size in shared object, consider re-linking
  
  MPlayer 1.0rc4-4.5.2 (C) 2000-2010 MPlayer Team
  
  mplayer: could not connect to socket
  
  mplayer: No such file or directory
  
  Failed to open LIRC support. You will not be able to use your remote control.
  
  
  
  Playing foo.mov.
  
  libavformat file format detected.
  
  [lavf] stream 0: video (h264), -vid 0
  
  [lavf] stream 1: audio (aac), -aid 0, -alang eng
  
  VIDEO:  [H264]  1280x720  24bpp  59.940 fps  2494.2 kbps (304.5 kbyte/s)
  
  ==========================================================================
  
  Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
  
  Selected video codec: [ffh264] vfm: ffmpeg (FFmpeg H.264)
  
  ==========================================================================
  
  ==========================================================================
  
  Opening audio decoder: [faad] AAC (MPEG2/4 Advanced Audio Coding)
  
  AUDIO: 44100 Hz, 2 ch, s16le, 128.0 kbit/9.07% (ratio: 15999->176400)
  
  Selected audio codec: [faad] afm: faad (FAAD AAC (MPEG-2/MPEG-4 Audio))
  
  ==========================================================================
  
  AO: [pulse] 44100Hz 2ch s16le (2 bytes per sample)
  
  Starting playback...
  
  Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
  
  VO: [vdpau] 1280x720 => 1280x720 Planar YV12

  I’d like to use ffmpeg, mencoder, or some other command-line video transcoder to re-sample this video to a lower framerate without loss of image quality. That is, each frame should remain as crisp as possible.

  Attempts

  ffmpeg -i foo.mov -r 25 -vcodec copy bar.mov

  • The target frame rate — 25fps — is achieved but individual frames are "blocky."

  mencoder -nosound -ovc copy foo.mov -ofps 25 -o bar.mov

  • Videos are effectively un-viewable.

  Help !

  This seems like a simple enough use case. I’m very surprised that obvious things are not working. Is there something wrong with my approach ?

• FFMPEG Incorrect frame size, How to resolve ?

  7 juin 2012, par RAGOpoR

  running on CentOS 5.6, is it possible to fix this issues ?

  [ragopor@xs1 livestream]$ ffmpeg -i hello.mp4 -f mpegts -acodec libmp3lame -ar 48000 -ab 64k -s 320×240 -vcodec libx264 -b 96k -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -subq 5 -trellis 1 -refs 1 -coder 0 -me_range 16 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 200k -maxrate 96k -bufsize 96k -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 30 -aspect 320:240 -g 30 -async 2 helloout.mp4
  
  FFmpeg version 0.6.1, Copyright (c) 2000-2010 the FFmpeg developers
  
    built on Dec  4 2010 15:35:31 with gcc 4.1.2 20080704 (Red Hat 4.1.2-48)
  
    configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --incdir=/usr/include --disable-avisynth --extra-cflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -fPIC' --enable-avfilter --enable-avfilter-lavf --enable-libdirac --enable-libfaac --enable-libfaad --enable-libfaadbin --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libx264 --enable-gpl --enable-nonfree --enable-postproc --enable-pthreads --enable-shared --enable-swscale --enable-vdpau --enable-version3 --enable-x11grab
  
    libavutil     50.15. 1 / 50.15. 1
  
    libavcodec    52.72. 2 / 52.72. 2
  
    libavformat   52.64. 2 / 52.64. 2
  
    libavdevice   52. 2. 0 / 52. 2. 0
  
    libavfilter    1.19. 0 /  1.19. 0
  
    libswscale     0.11. 0 /  0.11. 0
  
    libpostproc   51. 2. 0 / 51. 2. 0
  
  
  
  Seems stream 1 codec frame rate differs from container frame rate: 59.83 (29917/500) -> 29.92 (29917/1000)
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'hello.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isomavc1mp42
  
    Duration: 00:02:47.66, start: 0.000000, bitrate: 644 kb/s
  
      Stream #0.0(und): Audio: aac, 44100 Hz, stereo, s16, 102 kb/s
  
      Stream #0.1(und): Video: h264, yuv420p, 480x320 [PAR 1:1 DAR 3:2], 539 kb/s, 29.92 fps, 29.92 tbr, 29917 tbn, 59.83 tbc
  
  Incorrect frame size
  
  [ragopor@xs1 livestream]$