diff --git a/src/opus_demo.c b/src/opus_demo.c
index f8cdf0310863ce474ad8383367ba1f84ed6d70f7..72506b5d75821d98f1ab96cee0793fca91bb2286 100644
--- a/src/opus_demo.c
+++ b/src/opus_demo.c
@@ -637,7 +637,7 @@ int main(int argc, char *argv[])
             case 4: newsize=sampling_rate/25; break;
             case 5: newsize=3*sampling_rate/50; break;
             }
-            while (newsize < sampling_rate/25 && bitrate_bps-fabs(sweep_bps) <= 3*12*sampling_rate/newsize)
+            while (newsize < sampling_rate/25 && bitrate_bps-abs(sweep_bps) <= 3*12*sampling_rate/newsize)
                newsize*=2;
             if (newsize < sampling_rate/100 && frame_size >= sampling_rate/100)
             {