diff --git a/libavcodec/i386/snowdsp_mmx.c b/libavcodec/i386/snowdsp_mmx.c
index f2eb14b2b3..03f622b756 100644
--- a/libavcodec/i386/snowdsp_mmx.c
+++ b/libavcodec/i386/snowdsp_mmx.c
@@ -111,8 +111,7 @@ void ff_snow_horizontal_compose97i_sse2(DWTELEM *b, int width){
 
         i = 0;
         asm volatile(
-            "pcmpeqd    %%xmm7, %%xmm7        \n\t"
-            "psrad         $29, %%xmm7        \n\t"
+            "pslld          $1, %%xmm7        \n\t"
         ::);
         for(; i<w_l-7; i+=8){
             asm volatile(
@@ -157,25 +156,21 @@ void ff_snow_horizontal_compose97i_sse2(DWTELEM *b, int width){
                 "movdqu 20(%1), %%xmm6        \n\t"
                 "paddd    (%1), %%xmm2        \n\t"
                 "paddd  16(%1), %%xmm6        \n\t"
-                "movdqa %%xmm2, %%xmm0        \n\t"
-                "movdqa %%xmm6, %%xmm4        \n\t"
-                "pslld      $2, %%xmm2        \n\t"
-                "pslld      $2, %%xmm6        \n\t"
-                "psubd  %%xmm2, %%xmm0        \n\t"
-                "psubd  %%xmm6, %%xmm4        \n\t"
-                "psrad      $1, %%xmm0        \n\t"
-                "psrad      $1, %%xmm4        \n\t"
-                "movdqu   (%0), %%xmm2        \n\t"
-                "movdqu 16(%0), %%xmm6        \n\t"
-                "psubd  %%xmm0, %%xmm2        \n\t"
-                "psubd  %%xmm4, %%xmm6        \n\t"
+                "movdqu   (%0), %%xmm0        \n\t"
+                "movdqu 16(%0), %%xmm4        \n\t"
+                "paddd  %%xmm2, %%xmm0        \n\t"
+                "paddd  %%xmm6, %%xmm4        \n\t"
+                "psrad      $1, %%xmm2        \n\t"
+                "psrad      $1, %%xmm6        \n\t"
+                "paddd  %%xmm0, %%xmm2        \n\t"
+                "paddd  %%xmm4, %%xmm6        \n\t"
                 "movdqa %%xmm2, (%2)          \n\t"
                 "movdqa %%xmm6, 16(%2)        \n\t"
                 :: "r"(&src[i]), "r"(&b[i]), "r"(&temp[i])
                  : "memory"
                );
         }
-        snow_horizontal_compose_lift_lead_out(i, temp, src, b, width, w_r, 1, -W_AM, W_AO, W_AS);
+        snow_horizontal_compose_lift_lead_out(i, temp, src, b, width, w_r, 1, -W_AM, W_AO+1, W_AS);
     }
 
     {
@@ -291,10 +286,9 @@ void ff_snow_horizontal_compose97i_mmx(DWTELEM *b, int width){
         DWTELEM * const ref = b+w2 - 1;
 
         i = 1;
-        b[0] = b[0] + (((2 * ref[1] + W_BO-1) + 4 * b[0]) >> W_BS);
+        b[0] = b[0] + (((2 * ref[1] + W_BO) + 4 * b[0]) >> W_BS);
         asm volatile(
-            "pcmpeqd     %%mm7, %%mm7        \n\t"
-            "psrld         $29, %%mm7        \n\t"
+            "pslld          $1, %%mm7        \n\t"
            ::);
         for(; i<w_l-3; i+=4){
             asm volatile(
@@ -333,16 +327,12 @@ void ff_snow_horizontal_compose97i_mmx(DWTELEM *b, int width){
                 "movq   12(%1), %%mm6        \n\t"
                 "paddd    (%1), %%mm2        \n\t"
                 "paddd   8(%1), %%mm6        \n\t"
-                "pxor    %%mm0, %%mm0        \n\t" //note: the 2 xor could be avoided if we would flip the rounding direction
-                "pxor    %%mm4, %%mm4        \n\t"
-                "psubd   %%mm2, %%mm0        \n\t"
-                "psubd   %%mm6, %%mm4        \n\t"
-                "psrad      $1, %%mm0        \n\t"
-                "psrad      $1, %%mm4        \n\t"
-                "psubd   %%mm0, %%mm2        \n\t"
-                "psubd   %%mm4, %%mm6        \n\t"
                 "movq     (%0), %%mm0        \n\t"
                 "movq    8(%0), %%mm4        \n\t"
+                "paddd   %%mm2, %%mm0        \n\t"
+                "paddd   %%mm6, %%mm4        \n\t"
+                "psrad      $1, %%mm2        \n\t"
+                "psrad      $1, %%mm6        \n\t"
                 "paddd   %%mm0, %%mm2        \n\t"
                 "paddd   %%mm4, %%mm6        \n\t"
                 "movq    %%mm2, (%2)         \n\t"
@@ -351,7 +341,7 @@ void ff_snow_horizontal_compose97i_mmx(DWTELEM *b, int width){
                  : "memory"
                );
         }
-        snow_horizontal_compose_lift_lead_out(i, temp, src, b, width, w_r, 1, -W_AM, W_AO, W_AS);
+        snow_horizontal_compose_lift_lead_out(i, temp, src, b, width, w_r, 1, -W_AM, W_AO+1, W_AS);
     }
 
     {
diff --git a/libavcodec/snow.c b/libavcodec/snow.c
index 8f2f4c0944..71049dfae9 100644
--- a/libavcodec/snow.c
+++ b/libavcodec/snow.c
@@ -775,7 +775,7 @@ static av_always_inline void liftS(DWTELEM *dst, DWTELEM *src, DWTELEM *ref, int
     int i;
 
     assert(shift == 4);
-#define LIFTS(src, ref, inv) ((inv) ? (src) + (((ref) + 4*(src))>>shift): (16*4*(src) + 4*(ref) + 8 + (5<<27))/(5*16) - (1<<23))
+#define LIFTS(src, ref, inv) ((inv) ? (src) + (((ref) + 4*(src))>>shift): -((-16*4*(src) + 4*(ref) + add + 5 + (5<<27))/(5*16) - (1<<23)))
     if(mirror_left){
         dst[0] = LIFTS(src[0], mul*2*ref[0]+add, inverse);
         dst += dst_step;
@@ -1113,8 +1113,8 @@ static void horizontal_decompose97i(DWTELEM *b, int width){
     DWTELEM temp[width];
     const int w2= (width+1)>>1;
 
-    lift (temp+w2, b    +1, b      , 1, 2, 2, width, -W_AM, W_AO, W_AS, 1, 0);
-    liftS(temp   , b      , temp+w2, 1, 2, 1, width, -W_BM, W_BO, W_BS, 0, 0);
+    lift (temp+w2, b    +1, b      , 1, 2, 2, width,  W_AM, W_AO, W_AS, 1, 1);
+    liftS(temp   , b      , temp+w2, 1, 2, 1, width,  W_BM, W_BO, W_BS, 0, 0);
     lift5(b   +w2, temp+w2, temp   , 1, 1, 1, width,  W_CM, W_CO, W_CS, 1, 0);
     lift (b      , temp   , b   +w2, 1, 1, 1, width,  W_DM, W_DO, W_DS, 0, 0);
 }
@@ -1150,7 +1150,7 @@ static void vertical_decompose97iL0(DWTELEM *b0, DWTELEM *b1, DWTELEM *b2, int w
 #ifdef liftS
         b1[i] -= (W_BM*(b0[i] + b2[i])+W_BO)>>W_BS;
 #else
-        b1[i] = (16*4*b1[i] - 4*(b0[i] + b2[i]) + 8*5 + (5<<27)) / (5*16) - (1<<23);
+        b1[i] = (16*4*b1[i] - 4*(b0[i] + b2[i]) + W_BO*5 + (5<<27)) / (5*16) - (1<<23);
 #endif
     }
 }
@@ -1344,8 +1344,8 @@ void ff_snow_horizontal_compose97i(DWTELEM *b, int width){
 
     lift (temp   , b      , b   +w2, 1, 1, 1, width,  W_DM, W_DO, W_DS, 0, 1);
     lift5(temp+w2, b   +w2, temp   , 1, 1, 1, width,  W_CM, W_CO, W_CS, 1, 1);
-    liftS(b      , temp   , temp+w2, 2, 1, 1, width,  W_BM, W_BO-1, W_BS, 0, 1);
-    lift (b+1    , temp+w2, b      , 2, 1, 2, width, -W_AM, W_AO, W_AS, 1, 1);
+    liftS(b      , temp   , temp+w2, 2, 1, 1, width,  W_BM, W_BO, W_BS, 0, 1);
+    lift (b+1    , temp+w2, b      , 2, 1, 2, width,  W_AM, W_AO, W_AS, 1, 0);
 }
 
 static void vertical_compose97iH0(DWTELEM *b0, DWTELEM *b1, DWTELEM *b2, int width){
diff --git a/libavcodec/snow.h b/libavcodec/snow.h
index 19df4ad791..9dd66031cb 100644
--- a/libavcodec/snow.h
+++ b/libavcodec/snow.h
@@ -165,11 +165,11 @@ static av_always_inline void snow_horizontal_compose_lift_lead_out(int i, DWTELE
 
 static av_always_inline void snow_horizontal_compose_liftS_lead_out(int i, DWTELEM * dst, DWTELEM * src, DWTELEM * ref, int width, int w){
         for(; i<w; i++){
-            dst[i] = src[i] + ((ref[i] + ref[(i+1)]+W_BO-1 + 4 * src[i]) >> W_BS);
+            dst[i] = src[i] + ((ref[i] + ref[(i+1)]+W_BO + 4 * src[i]) >> W_BS);
         }
 
         if(width&1){
-            dst[w] = src[w] + ((2 * ref[w] + W_BO-1 + 4 * src[w]) >> W_BS);
+            dst[w] = src[w] + ((2 * ref[w] + W_BO + 4 * src[w]) >> W_BS);
         }
 }
 
diff --git a/tests/ffmpeg.regression.ref b/tests/ffmpeg.regression.ref
index 94ad71085e..ddca176149 100644
--- a/tests/ffmpeg.regression.ref
+++ b/tests/ffmpeg.regression.ref
@@ -141,9 +141,9 @@ f8f51fa737add17f7fecaefa118b57ed *./tests/data/a-ffv1.avi
 2654678 ./tests/data/a-ffv1.avi
 799d3db687f6cdd7a837ec156efc171f *./tests/data/out.yuv
 stddev:  0.00 PSNR:99.99 bytes:7602176
-9078723c943de5d79490f54b99e6ea9e *./tests/data/a-snow.avi
-156656 ./tests/data/a-snow.avi
-f2932084b52e2ede167c9ba21eae0656 *./tests/data/out.yuv
+958d649d09b7361d5f00b5b3fcccbcd2 *./tests/data/a-snow.avi
+156606 ./tests/data/a-snow.avi
+b19cb7f9134f922326028c6bb44e96de *./tests/data/out.yuv
 stddev: 23.14 PSNR:20.83 bytes:7602176
 ba999e86070aa971376e7f317a022c37 *./tests/data/a-snow53.avi
 3519486 ./tests/data/a-snow53.avi
diff --git a/tests/rotozoom.regression.ref b/tests/rotozoom.regression.ref
index c113e106dc..21fe28bb64 100644
--- a/tests/rotozoom.regression.ref
+++ b/tests/rotozoom.regression.ref
@@ -141,9 +141,9 @@ d72b0960e162d4998b9acbabb07e99ab *./tests/data/a-ffv1.avi
 3525804 ./tests/data/a-ffv1.avi
 dde5895817ad9d219f79a52d0bdfb001 *./tests/data/out.yuv
 stddev:  0.00 PSNR:99.99 bytes:7602176
-40a6e938ac2bd92ee12cd57925e86454 *./tests/data/a-snow.avi
-68758 ./tests/data/a-snow.avi
-1e356854142898c7c4aab4bfedadf235 *./tests/data/out.yuv
+2cfa1bdb443d04a890208a83fd239461 *./tests/data/a-snow.avi
+68872 ./tests/data/a-snow.avi
+64a0495b7ab53509d3b791465262795c *./tests/data/out.yuv
 stddev: 10.86 PSNR:27.40 bytes:7602176
 3d0da6aeec9b80c6ee0ff4b747bdd0f0 *./tests/data/a-snow53.avi
 2721980 ./tests/data/a-snow53.avi
diff --git a/tests/seek.regression.ref b/tests/seek.regression.ref
index 798632b239..d9d4b05ff5 100644
--- a/tests/seek.regression.ref
+++ b/tests/seek.regression.ref
@@ -2046,51 +2046,51 @@ ret: 0 st:-1 ts:-0.645825 flags:1
 ret: 0 st: 0 dts:0.040000 pts:0.040000 pos:9610 size:1075 flags:0
 ----------------
 tests/data/a-snow.avi
-ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2986 flags:1
+ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2987 flags:1
 ret: 0 st:-1 ts:-1.000000 flags:0
-ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2986 flags:1
+ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2987 flags:1
 ret: 0 st:-1 ts:1.894167 flags:1
-ret: 0 st: 0 dts:1.440000 pts:1.440000 pos:46794 size:3663 flags:1
+ret: 0 st: 0 dts:1.440000 pts:1.440000 pos:46908 size:3663 flags:1
 ret: 0 st: 0 ts:0.800000 flags:0
-ret: 0 st: 0 dts:0.960000 pts:0.960000 pos:31726 size:3478 flags:1
+ret: 0 st: 0 dts:0.960000 pts:0.960000 pos:31690 size:3478 flags:1
 ret:-1 st: 0 ts:-0.320000 flags:1
 ret:-1 st:-1 ts:2.576668 flags:0
 ret: 0 st:-1 ts:1.470835 flags:1
-ret: 0 st: 0 dts:1.440000 pts:1.440000 pos:46794 size:3663 flags:1
+ret: 0 st: 0 dts:1.440000 pts:1.440000 pos:46908 size:3663 flags:1
 ret: 0 st: 0 ts:0.360000 flags:0
-ret: 0 st: 0 dts:0.480000 pts:0.480000 pos:18006 size:3229 flags:1
+ret: 0 st: 0 dts:0.480000 pts:0.480000 pos:17990 size:3229 flags:1
 ret:-1 st: 0 ts:-0.760000 flags:1
 ret:-1 st:-1 ts:2.153336 flags:0
 ret: 0 st:-1 ts:1.047503 flags:1
-ret: 0 st: 0 dts:0.960000 pts:0.960000 pos:31726 size:3478 flags:1
+ret: 0 st: 0 dts:0.960000 pts:0.960000 pos:31690 size:3478 flags:1
 ret: 0 st: 0 ts:-0.040000 flags:0
-ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2986 flags:1
+ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2987 flags:1
 ret: 0 st: 0 ts:2.840000 flags:1
-ret: 0 st: 0 dts:1.920000 pts:1.920000 pos:63240 size:3635 flags:1
+ret: 0 st: 0 dts:1.920000 pts:1.920000 pos:63350 size:3635 flags:1
 ret: 0 st:-1 ts:1.730004 flags:0
-ret: 0 st: 0 dts:1.920000 pts:1.920000 pos:63240 size:3635 flags:1
+ret: 0 st: 0 dts:1.920000 pts:1.920000 pos:63350 size:3635 flags:1
 ret: 0 st:-1 ts:0.624171 flags:1
-ret: 0 st: 0 dts:0.480000 pts:0.480000 pos:18006 size:3229 flags:1
+ret: 0 st: 0 dts:0.480000 pts:0.480000 pos:17990 size:3229 flags:1
 ret: 0 st: 0 ts:-0.480000 flags:0
-ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2986 flags:1
+ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2987 flags:1
 ret: 0 st: 0 ts:2.400000 flags:1
-ret: 0 st: 0 dts:1.920000 pts:1.920000 pos:63240 size:3635 flags:1
+ret: 0 st: 0 dts:1.920000 pts:1.920000 pos:63350 size:3635 flags:1
 ret: 0 st:-1 ts:1.306672 flags:0
-ret: 0 st: 0 dts:1.440000 pts:1.440000 pos:46794 size:3663 flags:1
+ret: 0 st: 0 dts:1.440000 pts:1.440000 pos:46908 size:3663 flags:1
 ret: 0 st:-1 ts:0.200839 flags:1
-ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2986 flags:1
+ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2987 flags:1
 ret: 0 st: 0 ts:-0.920000 flags:0
-ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2986 flags:1
+ret: 0 st: 0 dts:0.000000 pts:0.000000 pos:5660 size:2987 flags:1
 ret: 0 st: 0 ts:2.000000 flags:1
-ret: 0 st: 0 dts:1.920000 pts:1.920000 pos:63240 size:3635 flags:1
+ret: 0 st: 0 dts:1.920000 pts:1.920000 pos:63350 size:3635 flags:1
 ret: 0 st:-1 ts:0.883340 flags:0
-ret: 0 st: 0 dts:0.960000 pts:0.960000 pos:31726 size:3478 flags:1
+ret: 0 st: 0 dts:0.960000 pts:0.960000 pos:31690 size:3478 flags:1
 ret:-1 st:-1 ts:-0.222493 flags:1
 ret:-1 st: 0 ts:2.680000 flags:0
 ret: 0 st: 0 ts:1.560000 flags:1
-ret: 0 st: 0 dts:1.440000 pts:1.440000 pos:46794 size:3663 flags:1
+ret: 0 st: 0 dts:1.440000 pts:1.440000 pos:46908 size:3663 flags:1
 ret: 0 st:-1 ts:0.460008 flags:0
-ret: 0 st: 0 dts:0.480000 pts:0.480000 pos:18006 size:3229 flags:1
+ret: 0 st: 0 dts:0.480000 pts:0.480000 pos:17990 size:3229 flags:1
 ret:-1 st:-1 ts:-0.645825 flags:1
 ----------------
 tests/data/a-snow53.avi