diff --git a/libavfilter/af_afftfilt.c b/libavfilter/af_afftfilt.c
index 26a077ad5f..87e50f57e9 100644
--- a/libavfilter/af_afftfilt.c
+++ b/libavfilter/af_afftfilt.c
@@ -304,19 +304,19 @@ static int filter_frame(AVFilterLink *inlink)
                 fft_temp[n].im = fft_out[n].im;
             }
         } else {
-        for (n = 0; n <= window_size / 2; n++) {
-            float fr, fi;
+            for (n = 0; n <= window_size / 2; n++) {
+                float fr, fi;
 
-            values[VAR_BIN] = n;
-            values[VAR_REAL] = fft_out[n].re;
-            values[VAR_IMAG] = fft_out[n].im;
+                values[VAR_BIN] = n;
+                values[VAR_REAL] = fft_out[n].re;
+                values[VAR_IMAG] = fft_out[n].im;
 
-            fr = av_expr_eval(s->real[ch], values, s);
-            fi = av_expr_eval(s->imag[ch], values, s);
+                fr = av_expr_eval(s->real[ch], values, s);
+                fi = av_expr_eval(s->imag[ch], values, s);
 
-            fft_temp[n].re = fr;
-            fft_temp[n].im = fi;
-        }
+                fft_temp[n].re = fr;
+                fft_temp[n].im = fi;
+            }
         }
 
         for (n = window_size / 2 + 1, x = window_size / 2 - 1; n < window_size; n++, x--) {