[FFmpeg-cvslog] avcodec/ffwavesynth: Fix backward lcg_seek()

[Michael Niedermayer]

ffmpeg | branch: release/4.1 | Michael Niedermayer <michael at niedermayer.cc> | Fri Jun 21 22:08:27 2019 +0200| [24ea2679e2c93891a6a4c5fbddad6c27e459c140] | committer: Michael Niedermayer

avcodec/ffwavesynth: Fix backward lcg_seek()

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit cf2bd3ce79b12256d7d129b2ada5ee649b9a27eb)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=24ea2679e2c93891a6a4c5fbddad6c27e459c140
---

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

diff --git a/libavcodec/ffwavesynth.c b/libavcodec/ffwavesynth.c
index a66113972b..cf8c780f3e 100644
--- a/libavcodec/ffwavesynth.c
+++ b/libavcodec/ffwavesynth.c
@@ -122,7 +122,7 @@ static void lcg_seek(uint32_t *s, int64_t dt)
         c = LCG_C;
     } else { /* coefficients for a step backward */
         a = LCG_AI;
-        c = (uint32_t)(LCG_AI * LCG_C);
+        c = (uint32_t)(-LCG_AI * LCG_C);
         dt = -dt;
     }
     while (dt) {