diff --git a/morituri/common/checksum.py b/morituri/common/checksum.py
index c8f7f45..94dd6f2 100644
--- a/morituri/common/checksum.py
+++ b/morituri/common/checksum.py
@@ -33,6 +33,7 @@ from morituri.common import task
 # checksums are not CRC's. a CRC is a specific type of checksum.
 
 SAMPLES_PER_FRAME = 588
+WORDS_PER_FRAME = SAMPLES_PER_FRAME * 2
 BYTES_PER_FRAME = SAMPLES_PER_FRAME * 4
 FRAMES_PER_SECOND = 75