From 3d5f03bbc8bba2929cc09b07d2731ae5d392e772 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Mon, 12 Feb 2024 19:40:07 +0100
Subject: [PATCH] avfilter/vf_signature: Dont crash on no frames

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavfilter/vf_signature.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavfilter/vf_signature.c b/libavfilter/vf_signature.c
index 758b6e5101..3858fe3070 100644
--- a/libavfilter/vf_signature.c
+++ b/libavfilter/vf_signature.c
@@ -379,6 +379,9 @@ static int xml_export(AVFilterContext *ctx, StreamContext *sc, const char* filen
     FILE* f;
     unsigned int pot3[5] = { 3*3*3*3, 3*3*3, 3*3, 3, 1 };
 
+    if (!sc->coarseend->last)
+        return AVERROR(EINVAL); // No frames ?
+
     f = avpriv_fopen_utf8(filename, "w");
     if (!f) {
         int err = AVERROR(EINVAL);