From 3a177a9cca924e097265b32f9282814f6b653e08 Mon Sep 17 00:00:00 2001
From: Luca Barbato <lu_zero@gentoo.org>
Date: Fri, 2 May 2014 00:21:23 +0200
Subject: [PATCH] swscale: Fix an undefined behaviour

Prevent a division by zero down the codepath.

Sample-Id: 00001721-google
Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
---
 libswscale/utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libswscale/utils.c b/libswscale/utils.c
index 6af41f8b30..fa00668c8e 100644
--- a/libswscale/utils.c
+++ b/libswscale/utils.c
@@ -331,7 +331,7 @@ static av_cold int initFilter(int16_t **outFilter, int32_t **filterPos,
 
         xDstInSrc = xInc - 0x10000;
         for (i = 0; i < dstW; i++) {
-            int xx = (xDstInSrc - ((filterSize - 2) << 16)) / (1 << 17);
+            int xx = (xDstInSrc - ((int64_t)(filterSize - 2) << 16)) / (1 << 17);
             int j;
             (*filterPos)[i] = xx;
             for (j = 0; j < filterSize; j++) {