diff --git a/coub-dl.py b/coub-dl.py
index 1d65c14..ea7bb28 100644
--- a/coub-dl.py
+++ b/coub-dl.py
@@ -38,19 +38,37 @@ def print_opt(*args, **kwargs):
         print(*args, **kwargs)
 
 
-def get_command_stderr(command):
-    process = Popen(command, stderr=PIPE, stdout=PIPE)
-    out, err = process.communicate()
-    return err
+def run(url, files_dict, directory):
+    # download streams and update FILE dict with extensions
+    download_audio_stream(url, files_dict)
+    download_video_stream(url, files_dict)
+    read_extensions(files_dict, directory)
 
+    # get stream lengths via ffprobe
+    audioLen = get_length(files_dict[Stream.AUDIO])
+    videoLen = get_length(files_dict[Stream.VIDEO])
 
-def get_duration(ffprobe_output):
-    durationPattern = r'.*Duration:\s(.+),\sstart.*'
-    regex = match(durationPattern, str(ffprobe_output))
-    duration = regex.groups()[0] if regex else None
-    if not duration:
-        raise ValueError('Cannot process ffprobe output!')
-    return duration
+    # decide which stream needs some looping
+    longer = audioLen if audioLen > videoLen else videoLen
+    shorter = audioLen if audioLen < videoLen else videoLen
+    shorterFile = files_dict[Stream.AUDIO] if audioLen < videoLen else files_dict[Stream.VIDEO]
+    files_dict[File.LOOP] += splitext(shorterFile)[1]
+    files_dict[File.FRACTION] += splitext(shorterFile)[1]
+
+    # calculate how many times to loop
+    times = longer.total_seconds() / shorter.total_seconds()
+    timesLoop_base = floor(times)
+    timesLoop_fraction = times % 1
+
+    # write concat helper file for ffmpeg
+    with open(files_dict[File.LIST], 'w') as f:
+        for i in range(timesLoop_base):
+            print("file '{}'".format(shorterFile), file=f)
+        print("file '{}'".format(files_dict[File.FRACTION]), file=f)
+
+    # loop & mux streams
+    loop_shorter_stream(files_dict, shorter, shorterFile, timesLoop_fraction)
+    mux_streams(files_dict)
 
 
 @call_verbose(before_message='Downloading audio stream... ')
@@ -78,6 +96,26 @@ def read_extensions(file_dict, directory):
                 file_dict[filename] = fullname
 
 
+def get_length(file):
+    data = get_duration(get_command_stderr(('ffprobe', file))).split(':')
+    return timedelta(hours=float(data[0]), minutes=float(data[1]), seconds=float(data[2]))
+
+
+def get_command_stderr(command):
+    process = Popen(command, stderr=PIPE, stdout=PIPE)
+    out, err = process.communicate()
+    return err
+
+
+def get_duration(ffprobe_output):
+    durationPattern = r'.*Duration:\s(.+),\sstart.*'
+    regex = match(durationPattern, str(ffprobe_output))
+    duration = regex.groups()[0] if regex else None
+    if not duration:
+        raise ValueError('Cannot process ffprobe output!')
+    return duration
+
+
 @call_verbose(before_message='Looping shorter stream... ')
 def loop_shorter_stream(file_dict, shorter, shorter_file, loop_fraction):
     # prepare last fractional loop
@@ -99,11 +137,6 @@ def mux_streams(file_dict):
          stdout=DEVNULL, stderr=DEVNULL)
 
 
-def get_length(file):
-    data = get_duration(get_command_stderr(('ffprobe', file))).split(':')
-    return timedelta(hours=float(data[0]), minutes=float(data[1]), seconds=float(data[2]))
-
-
 def determine_output_filename(url, user_supplied, extension, files_dict):
     if user_supplied is None:
         files_dict[File.OUTPUT] = check_output(('youtube-dl', '--get-title', url)).decode('utf-8').strip()
@@ -148,42 +181,12 @@ def yes_no_question(question, default):
             print("Please respond with 'yes'(y) or 'no'(n)!")
 
 
-def run(url, files_dict, directory):
-    # download streams and update FILE dict with extensions
-    download_audio_stream(url, files_dict)
-    download_video_stream(url, files_dict)
-    read_extensions(files_dict, directory)
-
-    # get stream lengths via ffprobe
-    audioLen = get_length(files_dict[Stream.AUDIO])
-    videoLen = get_length(files_dict[Stream.VIDEO])
-
-    # decide which stream needs some looping
-    longer = audioLen if audioLen > videoLen else videoLen
-    shorter = audioLen if audioLen < videoLen else videoLen
-    shorterFile = files_dict[Stream.AUDIO] if audioLen < videoLen else files_dict[Stream.VIDEO]
-    files_dict[File.LOOP] += splitext(shorterFile)[1]
-    files_dict[File.FRACTION] += splitext(shorterFile)[1]
-
-    times = longer.total_seconds() / shorter.total_seconds()
-    timesLoop_base = floor(times)
-    timesLoop_fraction = times % 1
-
-    # write concat helper file for ffmpeg
-    with open(files_dict[File.LIST], 'w') as f:
-        for i in range(timesLoop_base):
-            print("file '{}'".format(shorterFile), file=f)
-        print("file '{}'".format(files_dict[File.FRACTION]), file=f)
-
-    loop_shorter_stream(files_dict, shorter, shorterFile, timesLoop_fraction)
-    mux_streams(files_dict)
-
-
 
 if __name__ == '__main__':
     args = parse_cmd_arguments()
     VERBOSE = False if args.nonverbose else True
 
+    # create dict that contains files used
     FILES = {Stream.AUDIO: 'audio', Stream.VIDEO: 'video',
              File.LIST: 'list.txt', File.LOOP: 'loop', File.FRACTION: 'fraction',
              File.OUTPUT: 'output'+args.extension}
@@ -202,10 +205,10 @@ if __name__ == '__main__':
         else:
             remove(FILES[File.OUTPUT])
 
+    # create temporary directory to work in
     with TemporaryDirectory() as dir:
         # update temporary file locations in FILES dict
-        for key in FILES:
-            if key not in OUTPUT_KEYS:
-                FILES[key] = join(dir, FILES[key])
+        for key in {key: FILES[key] for key in FILES if key not in OUTPUT_KEYS}:
+            FILES[key] = join(dir, FILES[key])
 
         run(URL, FILES, dir)