1 files changed, 5 insertions, 0 deletions
diff --git a/sub/ass_mp.c b/sub/ass_mp.c
index 172701495f..45328fb920 100644
--- a/sub/ass_mp.c
+++ b/sub/ass_mp.c
@@ -240,6 +240,11 @@ static bool pack(struct mp_ass_packer *p, struct sub_bitmaps *res, int imgfmt)
         talloc_steal(p, p->cached_img);
     }
 
+    if (!mp_image_make_writeable(p->cached_img)) {
+        packer_reset(p->packer);
+        return false;
+    }
+
     res->packed = p->cached_img;
 
     for (int n = 0; n < res->num_parts; n++) {