Question

For example I am using ffplay and want to run this command -bufsize[:stream_specifier] integer (output,audio,video)

At the moment I have this:

subprocess.call(["ffplay", "-vn", "-nodisp","-bufsize 4096", "%s" % url])

But this says it is invalid.

Answer 1

As JBernardo mentioned in a comment, separate the "-bufsize 4096" argument into two, "-bufsize", "4096". Each argument needs to be separated when subprocess.call is used with shell=False (the default). You can also specify shell=True and give the whole command as a single string, but this is not recommended due to potential security vulnerabilities.

You should not need to use string formatting where you have "%s" % url. If url is a string, pass it directly, otherwise call str(url) to get a string representation.