[FFmpeg-cvslog] avcodec/snow_dwt: Fix left shifts of negative numbers

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at outlook.com> | Fri Oct 21 16:08:16 2022 +0200| [c76155236fdfab9eb02ac30d2d03380a0648fb84] | committer: Andreas Rheinhardt

avcodec/snow_dwt: Fix left shifts of negative numbers

Affected the vsynth(1|2|_lena)-snow(|-hpel) tests.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=c76155236fdfab9eb02ac30d2d03380a0648fb84
---

 libavcodec/snow_dwt.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libavcodec/snow_dwt.c b/libavcodec/snow_dwt.c
index 18b315ef66..965f409002 100644
--- a/libavcodec/snow_dwt.c
+++ b/libavcodec/snow_dwt.c
@@ -778,10 +778,10 @@ static inline int w_c(struct MpegEncContext *v, const uint8_t *pix1, const uint8
 
     for (i = 0; i < h; i++) {
         for (j = 0; j < w; j += 4) {
-            tmp[32 * i + j + 0] = (pix1[j + 0] - pix2[j + 0]) << 4;
-            tmp[32 * i + j + 1] = (pix1[j + 1] - pix2[j + 1]) << 4;
-            tmp[32 * i + j + 2] = (pix1[j + 2] - pix2[j + 2]) << 4;
-            tmp[32 * i + j + 3] = (pix1[j + 3] - pix2[j + 3]) << 4;
+            tmp[32 * i + j + 0] = (pix1[j + 0] - pix2[j + 0]) * (1 << 4);
+            tmp[32 * i + j + 1] = (pix1[j + 1] - pix2[j + 1]) * (1 << 4);
+            tmp[32 * i + j + 2] = (pix1[j + 2] - pix2[j + 2]) * (1 << 4);
+            tmp[32 * i + j + 3] = (pix1[j + 3] - pix2[j + 3]) * (1 << 4);
         }
         pix1 += line_size;
         pix2 += line_size;