Passing double quote shell commands in python to subprocess.Popen()?

Question

I\'ve been trying to pass a command that works only with literal double quotes in the commandline around the "concat:file1|file2" argument for ffmpeg.

Answer 1

I'd suggest using the list form of invocation rather than the quoted string version:

command = ["ffmpeg", "-i", "concat:1.ts|2.ts", "-vcodec", "copy",
           "-acodec", "copy", "temp.mp4"]
output,error  = subprocess.Popen(
                    command, universal_newlines=True,
                    stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()

This more accurately represents the exact set of parameters that are going to be passed to the end process and eliminates the need to mess around with shell quoting.

That said, if you absolutely want to use the plain string version, just use different quotes (and shell=True):

command = 'ffmpeg -i "concat:1.ts|2.ts" -vcodec copy -acodec copy temp.mp4'
output,error  = subprocess.Popen(
                    command, universal_newlines=True, shell=True,
                    stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()