Python : call ffmpeg command line with subprocess

Question

I'm trying to call simple ffmpeg command line with subprocess.call. (Example : ffmpeg -i input\video.mp4 -r 30 input\video.avi)

By typing directly the ffmpeg command it works, but when I try to call it with subprocess.call : subprocess.call('ffmpeg -i input\video.mp4 -r 30 input\video.avi', shell=True) there is no error, but it doesn't produce anything.

Any idea where can be the problem? (I'm working with python 3.4 or 2.7, I tried both)

unrelated: you don't need shell=True on Windows here.

jfs
– jfs

2015-01-15 16:55:38 +00:00
Commented Jan 15, 2015 at 16:55 — jfs
– jfs, Commented Jan 15, 2015 at 16:55

Eliiie · Accepted Answer · 2015-01-15 17:49:21Z

3

Finally found the problem : when you are using subprocess you MUST use

for your files location instead of

EDIT : or you can use raw-string literals -> r'ffmpeg -i input\video.mp4 ...' (notice: r'') or you can double them '\\' Thanks to J.F. Sebastian

edited Jan 15, 2015 at 17:49

answered Jan 15, 2015 at 14:59

Eliiie

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1 Comment

jfs Over a year ago

There is nothing special about subprocess. You could use raw-string literals for Windows paths that contain backslashes e.g., r'ffmpeg -i input\video.mp4 ...' (notice: r'') or you should double them '\\'

vks · Accepted Answer · 2014-11-16 17:25:22Z

0

x=subprocess.Popen('ffmpeg -i input\video.mp4 -r 30 input\video.avi', shell=True,stdout=subprocess.PIPE,stderr=subprocess.PIPE)
output,err=x.communicate()
if output:
      print "success ",output
else:
      print "error ",err

You can try this and check output and errors if any.

edited Nov 16, 2014 at 17:25

answered Nov 16, 2014 at 16:44

vks

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4 Comments

Eliiie Over a year ago

With the updated code I have : error b'' (I changed error to err, error wasn't defined)

vks Over a year ago

@Jacqueslelezard your ffmpeg command is not working properly.It is failing with error b.

Eliiie Over a year ago

I see that, but why? If I type exactly the same command without running it from python there is no any problem...

vks Over a year ago

@Jacqueslelezard have you checked the file location?is the script located at correct location?

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