diff --git a/doc/html/format.html b/doc/html/format.html
index 8598941c..4ccd7e78 100644
--- a/doc/html/format.html
+++ b/doc/html/format.html
@@ -1578,7 +1578,8 @@
 				<5>
 			</td>
 			<td>
-				Quantized linear predictor coefficient shift needed in bits (NOTE: this number is signed two's-complement).
+				Quantized linear predictor coefficient shift needed in bits (NOTE: this number is signed two's-complement;
+				but, due to implementation details, must be non-negative).
 			</td>
 		</tr>
 		<tr>