Deprecation warning due to invalid escape sequences in Python 3.8

Created by: tirkarthi

Deprecation warnings are raised due to invalid escape sequences in Python 3.8 . Below is a log of the warnings raised during compiling all the python files. Using raw strings or escaping them will fix this issue.

find . -iname '*.py'  | xargs -P 4 -I{} python -Walways -m py_compile {}
                      
./examples/split_silence.py:30: DeprecationWarning: invalid escape sequence \.
  silence_start_re = re.compile(' silence_start: (?P<start>[0-9]+(\.?[0-9]*))$')
./examples/split_silence.py:31: DeprecationWarning: invalid escape sequence \.
  silence_end_re = re.compile(' silence_end: (?P<end>[0-9]+(\.?[0-9]*)) ')
./examples/split_silence.py:33: DeprecationWarning: invalid escape sequence \.
  'size=[^ ]+ time=(?P<hours>[0-9]{2}):(?P<minutes>[0-9]{2}):(?P<seconds>[0-9\.]{5}) bitrate=')
./ffmpeg/tests/test_ffmpeg.py:33: DeprecationWarning: invalid escape sequence \:
  assert ffmpeg._utils.escape_chars('a:b', ':') == 'a\:b'