[FFmpeg-cvslog] avcodec/jpeg2000dec: Use 32x32->64bit for 9/7i dequantization

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Wed Jun 24 17:07:27 2015 +0200| [ffa1de8a3b93139097214bc600d356ab62bfdf05] | committer: Michael Niedermayer

avcodec/jpeg2000dec: Use 32x32->64bit for 9/7i dequantization

Like the 5/3 case this is needed to avoid overflows and similarly for 16bpp
output pure 32bit operations are insufficient if high quality is wanted

Note, this code-path is only used in bitexact mode, so this should not
affect the speed of any real use-case

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ffa1de8a3b93139097214bc600d356ab62bfdf05
---

 libavcodec/jpeg2000dec.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index 11f4cd6..43568ea 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -1457,7 +1457,7 @@ static void dequantization_int_97(int x, int y, Jpeg2000Cblk *cblk,
         int32_t *datap = &comp->i_data[(comp->coord[0][1] - comp->coord[0][0]) * (y + j) + x];
         int *src = t1->data[j];
         for (i = 0; i < w; ++i)
-            datap[i] = (src[i] * band->i_stepsize + (1<<14)) >> 15;
+            datap[i] = (src[i] * (int64_t)band->i_stepsize + (1<<14)) >> 15;
     }
 }