FFmpeg / python - command works when run from shell but fails when run from python

Question

I have a python script which should run an ffmpeg command with this function:

def transcode(in_path, out_path):
    cmd = ["ffmpeg", "-y", "-i", in_path, '-vf smartblur=lr=1']
    cmd += ["-an", out_path]
    print("Running:", " ".join(cmd))
    subprocess.run(cmd, stdout=cmdout, stderr=cmdout)

When I run the python script it fails with this ffmpeg error:

Running: ffmpeg -y -i raid/orig/scenes/train/5786088.mp4 -vf smartblur=lr=1 -an raid/4K/scenes/train/5786088.mp4
ffmpeg version 2.8.15-0ubuntu0.16.04.1 Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.10) 20160609
  configuration: --prefix=/usr --extra-version=0ubuntu0.16.04.1 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
Unrecognized option 'vf smartblur=lr=1'.
Error splitting the argument list: Option not found

You can see the command it tries to execute in the first line, when I run it in the command line it works fine. When I run the command in the shell it outputs the same version and parameters of the ffmpeg as written in the error above.

I feel like I missed something simple yet crucial, anyone can point me to the right direction?

You already have a solution, but the 2.8 branch is ancient. I recommend updating to avoid bugs that were fixed long ago [compile or download]. — llogan
– llogan, Commented Apr 4, 2019 at 17:30

andree · Accepted Answer · 2019-04-04 11:32:37Z

1

You probably have to split the "-vf smartblur" option like this:

cmd = ["ffmpeg", "-y", "-i", in_path, '-vf', 'smartblur=lr=1']

answered Apr 4, 2019 at 11:32

andree

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1 Comment

artembus Over a year ago

If I had glasses I'm pretty sure I would be looking for them 90% of the time while wearing them. That's so obvious I don't know how I missed it or how I didn't try it. Hope it will help some other poor soul with a similar problem.

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