diff --git a/libavcodec/dvbsubdec.c b/libavcodec/dvbsubdec.c
index a4663d997f..08f6a9bf85 100644
--- a/libavcodec/dvbsubdec.c
+++ b/libavcodec/dvbsubdec.c
@@ -810,7 +810,7 @@ static void compute_default_clut(AVSubtitleRect *rect, int w, int h)
         list_inv[     i ] = bestv;
     }
 
-    count = i - 1;
+    count = FFMAX(i - 1, 1);
     for (i--; i>=0; i--) {
         int v = i*255/count;
         AV_WN32(rect->data[1] + 4*list_inv[i], RGBA(v/2,v,v/2,v));