diff --git a/libavcodec/dcadec.c b/libavcodec/dcadec.c
index f8fa310c2f..1ba9863c62 100644
--- a/libavcodec/dcadec.c
+++ b/libavcodec/dcadec.c
@@ -1038,7 +1038,7 @@ static int dca_filter_channels(DCAContext *s, int block_index, int upsample)
             unsigned i;
             /* Should apply the filter in Table 6-11 when upsampling. For
              * now, just duplicate. */
-            for (i = 511; i > 0; i--) {
+            for (i = 255; i > 0; i--) {
                 samples[2 * i]     =
                 samples[2 * i + 1] = samples[i];
             }