--- a/ffmpeg/_ffmpeg.py
+++ b/ffmpeg/_ffmpeg.py
@@ -1,8 +1,5 @@
 from __future__ import unicode_literals
 
-from past.builtins import basestring
-from ._utils import basestring
-
 from .nodes import (
     filter_operator,
     GlobalNode,
@@ -81,7 +78,7 @@
     """
     streams_and_filename = list(streams_and_filename)
     if 'filename' not in kwargs:
-        if not isinstance(streams_and_filename[-1], basestring):
+        if not isinstance(streams_and_filename[-1], str):
             raise ValueError('A filename must be provided')
         kwargs['filename'] = streams_and_filename.pop(-1)
     streams = streams_and_filename
--- a/ffmpeg/_run.py
+++ b/ffmpeg/_run.py
@@ -1,6 +1,6 @@
 from __future__ import unicode_literals
 from .dag import get_outgoing_edges, topo_sort
-from ._utils import basestring, convert_kwargs_to_cmd_line_args
+from ._utils import convert_kwargs_to_cmd_line_args
 from builtins import str
 from functools import reduce
 import collections
@@ -136,7 +136,7 @@
         args += ['-b:a', str(kwargs.pop('audio_bitrate'))]
     if 'video_size' in kwargs:
         video_size = kwargs.pop('video_size')
-        if not isinstance(video_size, basestring) and isinstance(
+        if not isinstance(video_size, str) and isinstance(
             video_size, collections.Iterable
         ):
             video_size = '{}x{}'.format(video_size[0], video_size[1])
@@ -183,7 +183,7 @@
     This is the same as calling :meth:`get_args` except that it also
     includes the ``ffmpeg`` command as the first argument.
     """
-    if isinstance(cmd, basestring):
+    if isinstance(cmd, str):
         cmd = [cmd]
     elif type(cmd) != list:
         cmd = list(cmd)
--- a/ffmpeg/_utils.py
+++ b/ffmpeg/_utils.py
@@ -1,25 +1,8 @@
 from __future__ import unicode_literals
 from builtins import str
-from past.builtins import basestring
 import hashlib
 import sys
 
-if sys.version_info.major == 2:
-    # noinspection PyUnresolvedReferences,PyShadowingBuiltins
-    str = str
-
-
-# `past.builtins.basestring` module can't be imported on Python3 in some environments (Ubuntu).
-# This code is copy-pasted from it to avoid crashes.
-class BaseBaseString(type):
-    def __instancecheck__(cls, instance):
-        return isinstance(instance, (bytes, str))
-
-    def __subclasshook__(cls, thing):
-        # TODO: What should go here?
-        raise NotImplemented
-
-
 def with_metaclass(meta, *bases):
     class metaclass(meta):
         __call__ = type.__call__
@@ -33,26 +16,13 @@
     return metaclass('temporary_class', None, {})
 
 
-if sys.version_info.major >= 3:
-
-    class basestring(with_metaclass(BaseBaseString)):
-        pass
-
-
-else:
-    # noinspection PyUnresolvedReferences,PyCompatibility
-    from builtins import basestring
-
-
 def _recursive_repr(item):
     """Hack around python `repr` to deterministically represent dictionaries.
 
     This is able to represent more things than json.dumps, since it does not require things to be JSON serializable
     (e.g. datetimes).
     """
-    if isinstance(item, basestring):
-        result = str(item)
-    elif isinstance(item, list):
+    if isinstance(item, list):
         result = '[{}]'.format(', '.join([_recursive_repr(x) for x in item]))
     elif isinstance(item, dict):
         kv_pairs = [
--- a/ffmpeg/nodes.py
+++ b/ffmpeg/nodes.py
@@ -1,6 +1,5 @@
 from __future__ import unicode_literals
 
-from past.builtins import basestring
 from .dag import KwargReprNode
 from ._utils import escape_chars, get_hash_int
 from builtins import object
@@ -66,7 +65,7 @@
         """
         if self.selector is not None:
             raise ValueError('Stream already has a selector: {}'.format(self))
-        elif not isinstance(index, basestring):
+        elif not isinstance(index, str):
             raise TypeError("Expected string index (e.g. 'a'); got {!r}".format(index))
         return self.node.stream(label=self.label, selector=index)
 
--- a/ffmpeg/_run.py
+++ b/ffmpeg/_run.py
@@ -3,7 +3,6 @@
 from ._utils import convert_kwargs_to_cmd_line_args
 from builtins import str
 from functools import reduce
-import collections
 import copy
 import operator
 import subprocess
@@ -18,6 +17,11 @@
     output_operator,
 )
 
+try:
+    from collections.abc import Iterable
+except ImportError:
+    from collections import Iterable
+
 
 class Error(Exception):
     def __init__(self, cmd, stdout, stderr):
@@ -136,9 +140,7 @@
         args += ['-b:a', str(kwargs.pop('audio_bitrate'))]
     if 'video_size' in kwargs:
         video_size = kwargs.pop('video_size')
-        if not isinstance(video_size, str) and isinstance(
-            video_size, collections.Iterable
-        ):
+        if not isinstance(video_size, str) and isinstance(video_size, Iterable):
             video_size = '{}x{}'.format(video_size[0], video_size[1])
         args += ['-video_size', video_size]
     args += convert_kwargs_to_cmd_line_args(kwargs)