From 288dc5b4a11884b9a5cd62310abe99878544982b Mon Sep 17 00:00:00 2001
From: Tom Butterworth <bangnoise@gmail.com>
Date: Thu, 7 May 2015 21:21:46 +0100
Subject: [PATCH] avcodec/s3tc: fix alpha decoding when dimensions are not a
 multiple of 4

Fix alpha position error for edge blocks of odd-dimensioned frames

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
 libavcodec/s3tc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavcodec/s3tc.c b/libavcodec/s3tc.c
index 9886b1dc9c..a422874d17 100644
--- a/libavcodec/s3tc.c
+++ b/libavcodec/s3tc.c
@@ -71,8 +71,10 @@ static inline void dxt1_decode_pixels(GetByteContext *gb, uint32_t *d,
             pixels >>= 2;
             alpha  >>= 4;
         }
-        for (; x<4; x++)
+        for (; x<4; x++) {
             pixels >>= 2;
+            alpha  >>= 4;
+        }
         d += qstride;
     }
 }