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Re: using ffmpeg command line with python's subprocess module

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Chris Angelico <rosuav@gmail.com> writes:

> On Mon, Dec 2, 2013 at 10:34 PM, iMath <redstone-cold@163.com> wrote:
> > ffmpeg -f concat -i <(for f in ./*.wav; do echo "file '$f'"; done) -c copy output.wav
> > ffmpeg -f concat -i <(printf "file '%s'\n" ./*.wav) -c copy output.wav
> > ffmpeg -f concat -i <(find . -name '*.wav' -printf "file '%p'\n") -c copy output.wav
>
> In bash, the <(...) notation is like piping: it executes the command
> inside the parentheses and uses that as standard input to ffmpeg.

Not standard input, no. What it does is create a temporary file to
contain the result, and inserts that file name on the command line. This
is good for programs that require an actual file, not standard input.

So the above usage seems right to me: the ‘ffmpeg -i FOO’ option is
provided with a filename dynamically created by Bash, referring to a
temporary file that contains the output of the subshell.

-- 
 \     “Welchen Teil von ‘Gestalt’ verstehen Sie nicht?  [What part of |
  `\                ‘gestalt’ don't you understand?]” —Karsten M. Self |
_o__)                                                                  |
Ben Finney

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using ffmpeg command line with python's subprocess module iMath <redstone-cold@163.com> - 2013-12-02 03:34 -0800
  Re: using ffmpeg command line with python's subprocess module Chris Angelico <rosuav@gmail.com> - 2013-12-02 22:40 +1100
  Re: using ffmpeg command line with python's subprocess module Ben Finney <ben+python@benfinney.id.au> - 2013-12-03 08:19 +1100
    Re: using ffmpeg command line with python's subprocess module iMath <redstone-cold@163.com> - 2013-12-02 17:15 -0800
      Re: using ffmpeg command line with python's subprocess module rusi <rustompmody@gmail.com> - 2013-12-02 17:42 -0800
        Re: using ffmpeg command line with python's subprocess module iMath <redstone-cold@163.com> - 2013-12-03 17:42 -0800
        Re: using ffmpeg command line with python's subprocess module iMath <redstone-cold@163.com> - 2013-12-03 17:42 -0800
          Re: using ffmpeg command line with python's subprocess module Andreas Perstinger <andipersti@gmail.com> - 2013-12-04 10:38 +0100
            Re: using ffmpeg command line with python's subprocess module iMath <redstone-cold@163.com> - 2013-12-05 22:23 -0800
              Re: using ffmpeg command line with python's subprocess module Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-06 09:23 +0000
                Re: using ffmpeg command line with python's subprocess module iMath <redstone-cold@163.com> - 2013-12-06 06:52 -0800
                Re: using ffmpeg command line with python's subprocess module Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-06 15:12 +0000
                Re: using ffmpeg command line with python's subprocess module rusi <rustompmody@gmail.com> - 2013-12-06 07:15 -0800
                Re: using ffmpeg command line with python's subprocess module rusi <rustompmody@gmail.com> - 2013-12-06 07:13 -0800
                Re: using ffmpeg command line with python's subprocess module Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-06 15:34 +0000
                Re: using ffmpeg command line with python's subprocess module Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-06 15:53 +0000
                Re: using ffmpeg command line with python's subprocess module rusi <rustompmody@gmail.com> - 2013-12-06 08:19 -0800
                Re: using ffmpeg command line with python's subprocess module Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-06 16:25 +0000
                Re: using ffmpeg command line with python's subprocess module rusi <rustompmody@gmail.com> - 2013-12-06 08:45 -0800
                Re: using ffmpeg command line with python's subprocess module MRAB <python@mrabarnett.plus.com> - 2013-12-06 16:41 +0000
                Re: using ffmpeg command line with python's subprocess module rusi <rustompmody@gmail.com> - 2013-12-06 08:53 -0800
                Re: using ffmpeg command line with python's subprocess module Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-07 13:01 +1300
              Re: using ffmpeg command line with python's subprocess module Ned Batchelder <ned@nedbatchelder.com> - 2013-12-06 06:31 -0500
          Re: using ffmpeg command line with python's subprocess module Chris Angelico <rosuav@gmail.com> - 2013-12-04 21:51 +1100
            Re: using ffmpeg command line with python's subprocess module iMath <redstone-cold@163.com> - 2013-12-06 06:54 -0800
              Re: using ffmpeg command line with python's subprocess module Chris Angelico <rosuav@gmail.com> - 2013-12-07 01:59 +1100
                Re: using ffmpeg command line with python's subprocess module iMath <redstone-cold@163.com> - 2013-12-09 01:04 -0800
                Re: using ffmpeg command line with python's subprocess module Andreas Perstinger <andipersti@gmail.com> - 2013-12-10 13:59 +0100
    Re: using ffmpeg command line with python's subprocess module Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2013-12-03 10:33 +0100
      Re: using ffmpeg command line with python's subprocess module iMath <redstone-cold@163.com> - 2013-12-03 05:59 -0800
  Re: using ffmpeg command line with python's subprocess module Chris Angelico <rosuav@gmail.com> - 2013-12-03 08:25 +1100

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