diff --git a/libavcodec/snow.c b/libavcodec/snow.c
index db444f67e468ada2fdd332d454380f3c847c7443..aa569c28cec8a688d079cc2c084e20030e1316ec 100644
--- a/libavcodec/snow.c
+++ b/libavcodec/snow.c
@@ -4001,7 +4001,7 @@ static int decode_init(AVCodecContext *avctx)
     common_init(avctx);
 
     block_size = MB_SIZE >> s->block_max_depth;
-    slice_buffer_init(&s->sb, s->plane[0].height, (block_size) + (s->spatial_decomposition_count * (s->spatial_decomposition_count + 2)) + 1, s->plane[0].width, s->spatial_dwt_buffer);
+    slice_buffer_init(&s->sb, s->plane[0].height, (block_size) + (s->spatial_decomposition_count * (s->spatial_decomposition_count + 3)) + 1, s->plane[0].width, s->spatial_dwt_buffer);
 
     return 0;
 }