diff --git a/libavfilter/vf_interlace.c b/libavfilter/vf_interlace.c
index 39f60beaca..7cf2e1fc87 100644
--- a/libavfilter/vf_interlace.c
+++ b/libavfilter/vf_interlace.c
@@ -149,7 +149,7 @@ static void copy_picture_field(AVFrame *src_frame, AVFrame *dst_frame,
                     srcp_below = srcp; // there is no line below
                 for (i = 0; i < linesize; i++) {
                     // this calculation is an integer representation of
-                    // '0.5 * current + 0.25 * above + 0.25 + below'
+                    // '0.5 * current + 0.25 * above + 0.25 * below'
                     // '1 +' is for rounding.
                     dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
                 }
diff --git a/libavfilter/vf_tinterlace.c b/libavfilter/vf_tinterlace.c
index 5e3e058016..1f4de81fc7 100644
--- a/libavfilter/vf_tinterlace.c
+++ b/libavfilter/vf_tinterlace.c
@@ -202,7 +202,7 @@ void copy_picture_field(uint8_t *dst[4], int dst_linesize[4],
                 if (h == 1) srcp_below = srcp;     // there is no line below
                 for (i = 0; i < linesize; i++) {
                     // this calculation is an integer representation of
-                    // '0.5 * current + 0.25 * above + 0.25 + below'
+                    // '0.5 * current + 0.25 * above + 0.25 * below'
                     // '1 +' is for rounding. */
                     dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
                 }