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• ffmpeg output pipeing to named windows pipe

  23 août 2015, par Lucas

  This question is related to my previous question : Converting raw frames into webm live stream

  I want to pipe a video to ffmpeg and read it back through another pipe, but I cannot pipe the output of ffmpeg.exe to a named pipe on windows.

  My definition of the pipes in C# :

  NamedPipeServerStream p_to_ffmpeg;
  
  NamedPipeServerStream p_from_ffmpeg;
  
  p_to_ffmpeg = new NamedPipeServerStream("to_ffmpeg", PipeDirection.Out, 1, PipeTransmissionMode.Byte);
  
  p_from_ffmpeg = new NamedPipeServerStream("from_ffmpeg", PipeDirection.In, 1, PipeTransmissionMode.Byte);

  And then I start ffmpeg.exe in a separate process with the following options : -f rawvideo -vcodec rawvideo -video_size 656x492 -r 10 -pix_fmt rgb24 -i \\.\pipe\to_ffmpeg  -c:v libvpx  -pass 1 -f webm \\.\pipe\from_ffmpeg

  ffmpeg.exe refuses to write to the pipe with the following error : File '\\.\pipe\from_ffmpeg' already exists. Overwrite ? [y/N]

  When I replace the "output pipe" with a file name, it works like charm : -f rawvideo -vcodec rawvideo -video_size 656x492 -r 10 -pix_fmt rgb24 -i \\.\pipe\to_ffmpeg  -c:v libvpx  -pass 1 -f webm output.webm

  How do I get ffmpeg to write to a named pipe in windows ?

  Edit : When I force to write to the pipe with ffmpeg’s -y option, I get the following error : Could not write header for output file #0 (incorrect codec parameters ?): Error number -32 occurred

• ffmpeg in Python subprocess - Unable to find a suitable output format for 'pipe :'

  12 juillet 2016, par Spencer

  Trying to burn subs into video with ffmpeg via Python. Works fine in the command line, but when calling from Python subprocess with :

  p = subprocess.Popen('cd ~/Downloads/yt/; ffmpeg -i ./{video} -vf subtitles=./{subtitles} {out}.mp4'.format(video=vid.replace(' ', '\ '), subtitles=subs, out='out.mp4'), shell=True)

  I get :

  Unable to find a suitable output format for 'pipe:'

  Full traceback :

  'ffmpeg version 2.7.2 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.7.2_1 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-opencl --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid --enable-libfreetype --enable-libvpx --enable-libass --enable-libfdk-aac --enable-nonfree --enable-vda
  
    libavutil      54. 27.100 / 54. 27.100
  
    libavcodec     56. 41.100 / 56. 41.100
  
    libavformat    56. 36.100 / 56. 36.100
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 16.101 /  5. 16.101
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.100 /  1.  2.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from './OnHub - a router for the new way to Wi-Fi-HNnfHP7VDP8.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf56.36.100
  
    Duration: 00:00:53.94, start: 0.000000, bitrate: 2092 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 1961 kb/s, 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  [NULL @ 0x7fc07b077600] Unable to find a suitable output format for 'pipe:'
  
  pipe:: Invalid argument'

• How to make ffmpeg write its output to a named pipe

  15 septembre 2015, par Bastian35022

  I know i can make ffmpeg put its output to stdout and stderr using pipe:1 and pipe:2, respectively, as output_file parameter. (Docs)

  But what about named pipes, can i make it write to one ?

  If not, is there a way to redirect the data in stdout to a named pipe in Linux ? (something like ffmpeg <parameters> | pipe123</parameters>)

  This question is a follow-up of this question.