diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
index 4b6c2170d0..10a50bbfc7 100644
--- a/libavcodec/h264_slice.c
+++ b/libavcodec/h264_slice.c
@@ -980,7 +980,10 @@ static int init_dimensions(H264Context *h)
 
     /* handle container cropping */
     if (FFALIGN(h->avctx->width,  16) == FFALIGN(width,  16) &&
-        FFALIGN(h->avctx->height, 16) == FFALIGN(height, 16)) {
+        FFALIGN(h->avctx->height, 16) == FFALIGN(height, 16) &&
+        h->avctx->width  <= width &&
+        h->avctx->height <= height
+    ) {
         width  = h->avctx->width;
         height = h->avctx->height;
     }