Constrain encoder motion search range

Explicitly constrain the upper limit of motion search range (in the
unit of full pixel) to be [-1023, +1023]. It is intended to control
the effective motion search range for 4K sequences.

Change-Id: I645539c70885eec0f155781f439d97d333336e88

diff --git a/vp9/encoder/vp9_firstpass.c b/vp9/encoder/vp9_firstpass.c
index cbd321b..70d711c 100644 (file)
--- a/vp9/encoder/vp9_firstpass.c
+++ b/vp9/encoder/vp9_firstpass.c
@@ -406,8 +406,6 @@ static void first_pass_motion_search(VP9_COMP *cpi, MACROBLOCK *x,
   // for first pass test
   while ((quart_frm << sr) < MAX_FULL_PEL_VAL)
     sr++;
-  if (sr)
-    sr--;
 
   step_param    += sr;
   further_steps -= sr;

diff --git a/vp9/encoder/vp9_mcomp.c b/vp9/encoder/vp9_mcomp.c
index a52f5b1..a383164 100644 (file)
--- a/vp9/encoder/vp9_mcomp.c
+++ b/vp9/encoder/vp9_mcomp.c
@@ -51,9 +51,6 @@ int vp9_init_search_range(VP9_COMP *cpi, int size) {
   while ((size << sr) < MAX_FULL_PEL_VAL)
     sr++;
 
-  if (sr)
-    sr--;
-
   sr += cpi->sf.reduce_first_step_size;
   sr = MIN(sr, (cpi->sf.max_step_search_steps - 2));
   return sr;

diff --git a/vp9/encoder/vp9_mcomp.h b/vp9/encoder/vp9_mcomp.h
index bcab679..10c2e4f 100644 (file)
--- a/vp9/encoder/vp9_mcomp.h
+++ b/vp9/encoder/vp9_mcomp.h
@@ -18,8 +18,9 @@
 // The maximum number of steps in a step search given the largest
 // allowed initial step
 #define MAX_MVSEARCH_STEPS 11
-// Max full pel mv specified in 1 pel units
-#define MAX_FULL_PEL_VAL ((1 << (MAX_MVSEARCH_STEPS)) - 1)
+// Max full pel mv specified in the unit of full pixel
+// Enable the use of motion vector in range [-1023, 1023].
+#define MAX_FULL_PEL_VAL ((1 << (MAX_MVSEARCH_STEPS - 1)) - 1)
 // Maximum size of the first step in full pel units
 #define MAX_FIRST_STEP (1 << (MAX_MVSEARCH_STEPS-1))
 // Allowed motion vector pixel distance outside image border