[FFmpeg-devel] [PATCH v2] avcodec/apedec: fix prediction

[Zhao Zhili]

From: Zhao Zhili <zhilizhao at tencent.com>

Regression since ed0001482a74b60f3d5bc5.

Tested with:
./ffmpeg -i foo.ape -f md5 -
for samples in #9816 and #2239.

It gives the same result as before ed0001482a for ticket #9816,
and doesn't break ticket #2239.

Signed-off-by: Zhao Zhili <zhilizhao at tencent.com>
---
 libavcodec/apedec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
index a7c38bce1b..f5c0f75f7f 100644
--- a/libavcodec/apedec.c
+++ b/libavcodec/apedec.c
@@ -1198,7 +1198,7 @@ static av_always_inline int predictor_update_filter(APEPredictor64 *p,
                   p->buf[delayB - 3] * p->coeffsB[filter][3] +
                   p->buf[delayB - 4] * p->coeffsB[filter][4];
 
-    p->lastA[filter] = decoded + ((int64_t)((uint64_t)predictionA + (predictionB >> 1)) >> 10);
+    p->lastA[filter] = decoded + ((int32_t)((uint32_t)predictionA + ((int32_t)predictionB >> 1)) >> 10);
     p->filterA[filter] = p->lastA[filter] + ((int64_t)(p->filterA[filter] * 31ULL) >> 5);
 
     sign = APESIGN(decoded);
-- 
2.35.3