[FFmpeg-cvslog] avcodec/s3tc: fix alpha decoding when dimensions are not a multiple of 4

[Tom Butterworth]

ffmpeg | branch: master | Tom Butterworth <bangnoise at gmail.com> | Thu May  7 21:21:46 2015 +0100| [288dc5b4a11884b9a5cd62310abe99878544982b] | committer: Michael Niedermayer

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 at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=288dc5b4a11884b9a5cd62310abe99878544982b
---

 libavcodec/s3tc.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavcodec/s3tc.c b/libavcodec/s3tc.c
index 9886b1d..a422874 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;
     }
 }