diff --git a/ffmpeg.c b/ffmpeg.c
index a05d3c415526e7c6225cf2d22bb8017db44f58aa..6848f252e4fc2aa1ec833a4b682926f8d11bdeb2 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -2151,6 +2151,7 @@ static int poll_filters(void)
                     }
                     break;
                 }
+                frame_pts = AV_NOPTS_VALUE;
                 if (ost->enc->type == AVMEDIA_TYPE_VIDEO)
                     filtered_frame->pts = frame_pts = av_rescale_q(picref->pts, ist_pts_tb, AV_TIME_BASE_Q);
                 else if (picref->pts != AV_NOPTS_VALUE)