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• avutil/file_open : avoid file handle inheritance on Windows

  29 octobre 2015, par Tobias Rapp

  avutil/file_open : avoid file handle inheritance on Windows
  Avoids inheritance of file handles on Windows systems similar to the
  
  O_CLOEXEC/FD_CLOEXEC flag on Linux.
  Fixes file lock issues in Windows applications when a child process
  
  is started with handle inheritance enabled (standard input/output
  
  redirection) while a FFmpeg transcoding is running in the parent
  
  process.
  Links relevant to the subject :
  https://msdn.microsoft.com/en-us/library/w7sa2b22.aspx
  Describes the _wsopen() function and the O_NOINHERIT flag. File handles
  
  opened by _wsopen() are inheritable by default.
  https://msdn.microsoft.com/en-us/library/windows/desktop/ms682425%28v=vs.85%29.aspx
  Describes handle inheritance when creating new processes. Handle
  
  inheritance must be enabled (bInheritHandles = TRUE) e.g. when you want
  
  to pass handles for stdin/stdout via lpStartupInfo.
  Signed-off-by : Tobias Rapp <t.rapp@noa-audio.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavutil/file_open.c

• Sending 2 streams to FFmpeg from nodejs

  18 août 2019, par Sylens

  I am trying to send 2 ReadableStreams to FFmpeg from nodejs. I have tried using fluent-ffmpeg library to do this, but it only supports sending one stream for processing. Check here

  My problem is :
  I have 2 incoming mono audio streams, I want to send them to ffmpeg to create a stereo stream, which I will then send to google’s speech to text service, to generate a transcription.

  I am successfully receiving both the mono streams to the nodejs server.
  How to utilize FFmpeg to merge them in realtime is still unclear, I could spawn a FFmpeg child process, but I’m not sure how to give 2 ReadableStreams as inputs and get the output as another stream ? FFmpeg supports multiple input streams.

  I can merge the 2 mono streams if they are in two separate files with this code.

  const { spawn } = childProcess;
  
  const ffmpeg = spawn('ffmpeg', [
  
    '-i', this.phoneAudioFile,
  
    '-i', this.micAudioFile,
  
    '-filter_complex', '[0:a][1:a]amerge=inputs=2[a]',
  
    '-map', '[a]',
  
    this.outputLosslessFile,
  
  ]);

  How can I acheive the same using 2 streams instead of 2 files ?

  EDIT

  • The incoming streams both have PCM audio data.
  • This entire process runs on a linux Ubuntu server.
  • The final output must be a wav file.

• How to quit pexpect launched ffmpeg with key q pressed

  25 février 2014, par Shuman

  i used pexpect to call ffmpeg which is a lengthy process. it took half an hour, how can i detect user has pressed q key to stop it ? just like when you press q when using ffmpeg command line tool

  the ffmpeg command line is
  ffmpeg -y -i url -c copy -absf aac_adtstoasc out.mp4

  the last line of ffmpeg output is

  ...
  
  Stream mapping:
  
    Stream #0:1 -> #0:0 (copy)
  
    Stream #0:2 -> #0:1 (copy)
  
  Press [q] to stop, [?] for help
  
  frame=   84 fps= 77 q=-1.0 Lsize=  184626kB time=00:00:06.96 bitrate=217120.3kbits/s

  the code i have now is

  reo = re.compile("""\S+\s+(?P\d+)  # frame
  
                       \s\S+\s+(?P<fps>\d+)           # fps
  
                       \sq=(?P<q>\S+)                    # q
  
                       \s\S+\s+(?P<size>\S+)          # size
  
                       \stime=(?P<time>\S+)           # time
  
                       \sbitrate=(?P<bitrate>[\d\.]+) # bitrate
  
                       """, re.X)
  
  
  
  durationReo = (&#39;(?&lt;=Duration:\s)\S+(?=,)&#39;)
  
  
  
  cpl = thread.compile_pattern_list([
  
      pexpect.EOF,
  
      reo,
  
      durationReo
  
  ])
  
  
  
  while True:
  
      i = thread.expect_list(cpl, timeout=None)
  
      if i == 0: # EOF
  
          print "the sub process exited"
  
          break
  
      elif i == 1:
  
          frame_number = thread.match.group(0)
  
          print frame_number
  
          print reo.search(frame_number).groups()
  
          # thread.close
  
      elif i == 2:
  
          durationLine = thread.match.group(0)
  
          print &#39;Duration:&#39;, durationLine
  
          # print "something :",thread.match.group(1)
  
          pass
  
  </bitrate></time></size></q></fps>

  with this code i can already get the frame info and duration info, the ultimate goal is to create a textual progress bar with another python progressbar module. but with the ability to send the 'q' pressed signal to ffmpeg child process.