Simplify rate-distortion modeling function

Use left shift to replace one multiplication. The computation
outcome remains identical.

Change-Id: I1e1737af0a245de0d2a2bde10f0c171477199fc1

3 files changed, 12 insertions, 12 deletions

diff --git a/vp9/encoder/vp9_pickmode.c b/vp9/encoder/vp9_pickmode.c
index b45032456..d5ab0cc6c 100644
--- a/vp9/encoder/vp9_pickmode.c
+++ b/vp9/encoder/vp9_pickmode.c
@@ -249,14 +249,14 @@ static void model_rd_for_sb_y(VP9_COMP *cpi, BLOCK_SIZE bsize,
 
 #if CONFIG_VP9_HIGHBITDEPTH
   if (xd->cur_buf->flags & YV12_FLAG_HIGHBITDEPTH) {
-    vp9_model_rd_from_var_lapndz(sse - var, 1 << num_pels_log2_lookup[bsize],
+    vp9_model_rd_from_var_lapndz(sse - var, num_pels_log2_lookup[bsize],
                                  dc_quant >> (xd->bd - 5), &rate, &dist);
   } else {
-    vp9_model_rd_from_var_lapndz(sse - var, 1 << num_pels_log2_lookup[bsize],
+    vp9_model_rd_from_var_lapndz(sse - var, num_pels_log2_lookup[bsize],
                                  dc_quant >> 3, &rate, &dist);
   }
 #else
-  vp9_model_rd_from_var_lapndz(sse - var, 1 << num_pels_log2_lookup[bsize],
+  vp9_model_rd_from_var_lapndz(sse - var, num_pels_log2_lookup[bsize],
                                dc_quant >> 3, &rate, &dist);
 #endif  // CONFIG_VP9_HIGHBITDEPTH
 
@@ -265,14 +265,14 @@ static void model_rd_for_sb_y(VP9_COMP *cpi, BLOCK_SIZE bsize,
 
 #if CONFIG_VP9_HIGHBITDEPTH
   if (xd->cur_buf->flags & YV12_FLAG_HIGHBITDEPTH) {
-    vp9_model_rd_from_var_lapndz(var, 1 << num_pels_log2_lookup[bsize],
+    vp9_model_rd_from_var_lapndz(var, num_pels_log2_lookup[bsize],
                                  ac_quant >> (xd->bd - 5), &rate, &dist);
   } else {
-    vp9_model_rd_from_var_lapndz(var, 1 << num_pels_log2_lookup[bsize],
+    vp9_model_rd_from_var_lapndz(var, num_pels_log2_lookup[bsize],
                                  ac_quant >> 3, &rate, &dist);
   }
 #else
-  vp9_model_rd_from_var_lapndz(var, 1 << num_pels_log2_lookup[bsize],
+  vp9_model_rd_from_var_lapndz(var, num_pels_log2_lookup[bsize],
                                ac_quant >> 3, &rate, &dist);
 #endif  // CONFIG_VP9_HIGHBITDEPTH
 
diff --git a/vp9/encoder/vp9_rd.c b/vp9/encoder/vp9_rd.c
index 5b49bfc17..34d49f058 100644
--- a/vp9/encoder/vp9_rd.c
+++ b/vp9/encoder/vp9_rd.c
@@ -379,7 +379,7 @@ static void model_rd_norm(int xsq_q10, int *r_q10, int *d_q10) {
   *d_q10 = (dist_tab_q10[xq] * b_q10 + dist_tab_q10[xq + 1] * a_q10) >> 10;
 }
 
-void vp9_model_rd_from_var_lapndz(unsigned int var, unsigned int n,
+void vp9_model_rd_from_var_lapndz(unsigned int var, unsigned int n_log2,
                                   unsigned int qstep, int *rate,
                                   int64_t *dist) {
   // This function models the rate and distortion for a Laplacian
@@ -395,10 +395,10 @@ void vp9_model_rd_from_var_lapndz(unsigned int var, unsigned int n,
     int d_q10, r_q10;
     static const uint32_t MAX_XSQ_Q10 = 245727;
     const uint64_t xsq_q10_64 =
-        ((((uint64_t)qstep * qstep * n) << 10) + (var >> 1)) / var;
+        (((uint64_t)qstep * qstep << (n_log2 + 10)) + (var >> 1)) / var;
     const int xsq_q10 = (int)MIN(xsq_q10_64, MAX_XSQ_Q10);
     model_rd_norm(xsq_q10, &r_q10, &d_q10);
-    *rate = (n * r_q10 + 2) >> 2;
+    *rate = ((r_q10 << n_log2) + 2) >> 2;
     *dist = (var * (int64_t)d_q10 + 512) >> 10;
   }
 }
diff --git a/vp9/encoder/vp9_rdopt.c b/vp9/encoder/vp9_rdopt.c
index c47dccd7f..bc5edc815 100644
--- a/vp9/encoder/vp9_rdopt.c
+++ b/vp9/encoder/vp9_rdopt.c
@@ -265,15 +265,15 @@ static void model_rd_for_sb(VP9_COMP *cpi, BLOCK_SIZE bsize,
     } else {
 #if CONFIG_VP9_HIGHBITDEPTH
       if (xd->cur_buf->flags & YV12_FLAG_HIGHBITDEPTH) {
-        vp9_model_rd_from_var_lapndz(sum_sse, 1 << num_pels_log2_lookup[bs],
+        vp9_model_rd_from_var_lapndz(sum_sse, num_pels_log2_lookup[bs],
                                      pd->dequant[1] >> (xd->bd - 5),
                                      &rate, &dist);
       } else {
-        vp9_model_rd_from_var_lapndz(sum_sse, 1 << num_pels_log2_lookup[bs],
+        vp9_model_rd_from_var_lapndz(sum_sse, num_pels_log2_lookup[bs],
                                      pd->dequant[1] >> 3, &rate, &dist);
       }
 #else
-      vp9_model_rd_from_var_lapndz(sum_sse, 1 << num_pels_log2_lookup[bs],
+      vp9_model_rd_from_var_lapndz(sum_sse, num_pels_log2_lookup[bs],
                                    pd->dequant[1] >> 3, &rate, &dist);
 #endif  // CONFIG_VP9_HIGHBITDEPTH
       rate_sum += rate;