diff --git a/libavcodec/ac3.c b/libavcodec/ac3.c
index 29e132f5d1..c4fc77cbdf 100644
--- a/libavcodec/ac3.c
+++ b/libavcodec/ac3.c
@@ -200,9 +200,9 @@ int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd,
             if (band >= AC3_CRITICAL_BANDS || dba_lengths[seg] > AC3_CRITICAL_BANDS-band)
                 return -1;
             if (dba_values[seg] >= 4) {
-                delta = (dba_values[seg] - 3) << 7;
+                delta = (dba_values[seg] - 3) * 128;
             } else {
-                delta = (dba_values[seg] - 4) << 7;
+                delta = (dba_values[seg] - 4) * 128;
             }
             for (i = 0; i < dba_lengths[seg]; i++) {
                 mask[band++] += delta;