From f80b381bfd956e4470bdbc1854f88cf3ea0764a9 Mon Sep 17 00:00:00 2001
From: Stefano Sabatini <stefano.sabatini-lala@poste.it>
Date: Wed, 30 Mar 2011 21:30:31 +0200
Subject: [PATCH] graphparser: add a NULL check on the argument passed to
 strstr

Fix crash in create_filter() which occurrs if a scale filter with no
args is provided.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
---
 libavfilter/graphparser.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavfilter/graphparser.c b/libavfilter/graphparser.c
index dddb0a2070..00fb57ad57 100644
--- a/libavfilter/graphparser.c
+++ b/libavfilter/graphparser.c
@@ -121,7 +121,7 @@ static int create_filter(AVFilterContext **filt_ctx, AVFilterGraph *ctx, int ind
         return ret;
     }
 
-    if (!strcmp(filt_name, "scale") && !strstr(args, "flags")) {
+    if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags")) {
         snprintf(tmp_args, sizeof(tmp_args), "%s:%s",
                  args, ctx->scale_sws_opts);
         args = tmp_args;