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• ffmpeg set duration when muxing from fifos to pipe [migrated]

  26 mars 2014, par filoozom

  I'm trying to mux two files (audio and video) coming from fifos and to output the result to a pipe.
  The input files are one mp4 h264 file and a m4a aac, and the output file should be a matroska container because to my knowledge it's not possible to write a mp4 on a pipe or fifo, because it's not seekable.

  So I'm using the command

  ffmpeg -i /tmp/audio_fifo.m4a -i /tmp/video_fifo.mp4 -acodec copy -vcodec copy -strict -2 -f matroska pipe:1

  to just copy the video and audio content into the matroska container without converting anything, to make it fast and less CPU intensive.

  The problem is that the duration of both source files is not kept. I get a mkv file that can be read, but has an undefined duration (VLC shows 0:00, and it's not possible to browse in the video). My question is : is it possible to write the duration into the mkv container when it's written to a pipe ? Assuming I know the duration from the input files.

• Pipe input in to ffmpeg stdin

  3 juin 2021, par AbstractDissonance

  I am trying to use ffmpeg to decode audio data. While it works to load from a file, I would like to avoid using files because to do so, means I would have to use a temporary. Instead, I'd like to pipe in the data(which I've previously loaded) using stdin.

  



  Is this possible ?

  



  e.g.,

  



  

  1. Manually load mp3 file

  


  2. Pipe it in to the ffmpeg spawned process

  


  3. Get raw output

  


  



  (it should work with ffprobe and ffplay also)

  


• ffmpeg pipe:0 : could not find codec parameters

  13 octobre 2016, par dre

  When i run this command i get an error. If i run without the pipe, it works.

  With Pipe

  cat mymovie.m4v | ffmpeg -i pipe:0 -an -analyzeduration 1000000 -f image2 -vf 
  
  "select='eq(pict_type,PICT_TYPE_I)'" -vsync vfr 'public/files/thumb%04d.png'

  Without Pipe (Works)

  ffmpeg -i mymovie.m4v -an -analyzeduration 2147483647 -probesize 2147483647 -f image2 -vf 
  
  "select='eq(pict_type,PICT_TYPE_I)'" -vsync vfr 'public/files/thumb%04d.png'

  Output

  ffmpeg version 2.2 Copyright (c) 2000-2014 the FFmpeg developers
  
  built on Apr 10 2014 17:50:46 with Apple LLVM version 5.1 (clang-503.0.38) 
  
  (based on LLVM 3.4svn)
  
  configuration: --prefix=/usr/local/Cellar/ffmpeg/2.2 
  
  --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree 
  
  --enable-hardcoded-tables --enable-avresample --enable-vda --cc=clang 
  
  --host-cflags= --host-ldflags= --enable-libx264 --enable-libfaac --enable-libmp3lame 
  
  --enable-libxvid --enable-libfreetype --enable-libtheora --enable-libvorbis 
  
  --enable-libvpx --enable-librtmp --enable-libopencore-amrnb --enable-libopencore-amrwb
  
  --enable-libvo-aacenc --enable-libass --enable-ffplay --enable-libspeex 
  
  --enable-libschroedinger --enable-libfdk-aac --enable-libopus --enable-frei0r 
  
  --enable-libopenjpeg --extra-cflags='-
  
  
  
  I/usr/local/Cellar/openjpeg/1.5.1_1/include/openjpeg-1.5 '
  
    libavutil      52. 66.100 / 52. 66.100
  
    libavcodec     55. 52.102 / 55. 52.102
  
    libavformat    55. 33.100 / 55. 33.100
  
    libavdevice    55. 10.100 / 55. 10.100
  
    libavfilter     4.  2.100 /  4.  2.100
  
    libavresample   1.  2.  0 /  1.  2.  0
  
    libswscale      2.  5.102 /  2.  5.102
  
    libswresample   0. 18.100 /  0. 18.100
  
    libpostproc    52.  3.100 / 52.  3.100
  
  
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fd87b80f000] stream 0, offset 0x2c: partial file
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fd87b80f000] Could not find codec parameters for stream 0
  
  (Video: h264 (avc1 / 0x31637661), 1280x720, 3310 kb/s): unspecified pixel format

  Consider increasing the value for the ’analyzeduration’ and ’probesize’ options
  pipe:0 : could not find codec parameters

  I have tried setting (link)

  -analyzeduration100 -probesize 10000000 
  
  -analyzeduration 2147483647 -probesize 2147483647

  Still didn’t work.