diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index 06ded4d1f1..02ff83309f 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -1799,6 +1799,12 @@ static int decode_slice_header(H264Context *h, H264Context *h0){
     else
         s->height= 16*s->mb_height - 4*FFMIN(h->sps.crop_bottom, 3);
 
+    if (FFALIGN(s->avctx->width,  16) == s->width &&
+        FFALIGN(s->avctx->height, 16) == s->height) {
+        s->width  = s->avctx->width;
+        s->height = s->avctx->height;
+    }
+
     if (s->context_initialized
         && (   s->width != s->avctx->width || s->height != s->avctx->height
             || av_cmp_q(h->sps.sar, s->avctx->sample_aspect_ratio))) {