diff --git a/picard/disc/eaclog.py b/picard/disc/eaclog.py
index 658f3075d..5de3b3d72 100644
--- a/picard/disc/eaclog.py
+++ b/picard/disc/eaclog.py
@@ -48,6 +48,9 @@ RE_TOC_TABLE_LINE = re.compile(r"""
     \s*$""", re.VERBOSE)
 
 
+PREGAP_LENGTH = 150
+
+
 class NotSupportedTOCError(Exception):
     pass
 
@@ -75,20 +78,21 @@ def filter_toc_entries(lines):
 
 def calculate_mb_toc_numbers(eac_entries):
     """
-    Take iterator of toc entries, return list of numbers for musicbrainz disc id
+    Take iterator of toc entries, return a tuple of numbers for musicbrainz disc id
     """
-    eac = list(eac_entries)
+    eac = tuple(eac_entries)
     num_tracks = len(eac)
     if not num_tracks:
         raise NotSupportedTOCError("Empty track list: %s", eac)
 
-    tracknums = [int(e['num']) for e in eac]
-    if list(range(1, num_tracks+1)) != tracknums:
+    expected_tracknums = tuple(range(1, num_tracks+1))
+    tracknums = tuple(int(e['num']) for e in eac)
+    if expected_tracknums != tracknums:
         raise NotSupportedTOCError("Non-standard track number sequence: %s", tracknums)
 
-    leadout_offset = int(eac[-1]['end_sector']) + 150 + 1
-    offsets = [(int(x['start_sector']) + 150) for x in eac]
-    return [1, num_tracks, leadout_offset] + offsets
+    leadout_offset = int(eac[-1]['end_sector']) + PREGAP_LENGTH + 1
+    offsets = tuple((int(x['start_sector']) + PREGAP_LENGTH) for x in eac)
+    return (1, num_tracks, leadout_offset) + offsets
 
 
 def toc_from_file(path):
diff --git a/test/test_disc_eaclog.py b/test/test_disc_eaclog.py
index 96fbf3053..652ad6727 100644
--- a/test/test_disc_eaclog.py
+++ b/test/test_disc_eaclog.py
@@ -79,7 +79,7 @@ class TestFilterTocEntries(PicardTestCase):
 class TestCalculateMbTocNumbers(PicardTestCase):
 
     def test_calculate_mb_toc_numbers(self):
-        self.assertEqual([1, 3, 60890, 150, 25064, 43611], calculate_mb_toc_numbers(test_entries))
+        self.assertEqual((1, 3, 60890, 150, 25064, 43611), calculate_mb_toc_numbers(test_entries))
 
     def test_calculate_mb_toc_numbers_invalid_track_numbers(self):
         entries = [{'num': '1'}, {'num': '3'}, {'num': '4'}]
@@ -96,7 +96,7 @@ class TestTocFromFile(PicardTestCase):
     def _test_toc_from_file(self, logfile):
         test_log = get_test_data_path(logfile)
         toc = toc_from_file(test_log)
-        self.assertEqual([1, 8, 149323, 150, 25064, 43611, 60890, 83090, 100000, 115057, 135558], toc)
+        self.assertEqual((1, 8, 149323, 150, 25064, 43611, 60890, 83090, 100000, 115057, 135558), toc)
 
     def test_toc_from_file_eac(self):
         self._test_toc_from_file('eac.log')