diff --git a/sorter.py b/sorter.py
index 5dec32dbe5d228d80da06280524d056ff4e45c2b..1a1df26de5c83cf1104a17c10779056a894ea138 100644
--- a/sorter.py
+++ b/sorter.py
@@ -73,7 +73,7 @@ def insert_transcoded_video(jobid, jobtype, data, state, status):
 		return
 	insert_video(data['lecture_id'], data['output']['path'], data['format_id'], status['hash'], status['filesize'], status['duration'], data['source_id'] )
 
-def parseVideoFileName(splitFileName):
+def parse_file_name(splitFileName):
 	# filenames: <handle>-<sorter>-<format>.mp4
 	data = {'keywords': []}
 	for fileNameChunk in splitFileName:
@@ -94,7 +94,7 @@ def parseVideoFileName(splitFileName):
 			data['keywords'].append(fileNameChunk)
 	return data
 
-def matchDatetimeOnLecture(lectures, date, time):
+def filter_lectures_by_datetime(lectures, date, time):
 	matches = []
 	if date or time:
 		for lecture in lectures:
@@ -107,7 +107,7 @@ def matchDatetimeOnLecture(lectures, date, time):
 			matches.append(lecture)
 	return matches
 
-def matchKeywordsOnLecture(lectures, keywords):
+def filter_lectures_by_keywords(lectures, keywords):
 	for field in ['title','speaker','comment','internal']:
 		for lecture in lectures:
 			for keyword in keywords:
@@ -117,7 +117,7 @@ def matchKeywordsOnLecture(lectures, keywords):
 					return [lecture]
 	return []
 
-def matchFileNameOnFormat(splitFileName):
+def filter_formats_by_filename(splitFileName):
 	# default format is "unknown", with id 0
 	formats = query('SELECT * FROM formats ORDER BY prio DESC')
 	for videoformat in formats:
@@ -141,19 +141,19 @@ def sort_file(filename, course=None, lectures=None):
 	if not lectures:
 		lectures = query('SELECT * from lectures where course_id = ?', course['id'])
 	# parse all data from the file name
-	data = parseVideoFileName(splitFileName)
+	data = parse_file_name(splitFileName)
 	# try to match the file on a single lecture
-	matches = matchDatetimeOnLecture(lectures, data.get('date'), data.get('time'))
+	matches = filter_lectures_by_datetime(lectures, data.get('date'), data.get('time'))
 	# if we can't match exactly  based on date and time, we have to match keywords
 	if ((len(matches) != 1) and (len(data['keywords']) > 0)):
 		if not len(matches) == 0:
 			# only test lectures with the correct date/time, if we have any
-			matches = matchKeywordsOnLecture(matches, data['keywords'])
+			matches = filter_lectures_by_keywords(matches, data['keywords'])
 		else:
 			# Else test for matches in all lectures of this course
-			matches = matchKeywordsOnLecture(lectures, data['keywords'])
+			matches = filter_lectures_by_keywords(lectures, data['keywords'])
 	# now we should have found exactly one match
-	fmt = matchFileNameOnFormat(splitFileName)
+	fmt = filter_formats_by_filename(splitFileName)
 	return matches, fmt
 
 def log_sort_error(course_id, path, matches):