Adjust gm parameter computation to avoid mismatch

The gm parameters need to have WARPED_PRECISION_BITS precision
until they are written to the bitstream because functions in
reconinter use these parameters before they are written to
the bitstream. Previously, the parameters weren't being converted
to WARPED_PRECISION_BITS until they were read from the bitstream
which causes an encode/decode mismatch.

Change-Id: I31e76e9d6f7d24df21af287a72f8c01f1997304d

diff --git a/vp10/common/mv.h b/vp10/common/mv.h
index f45f2ab49c5559ea29236169715bd63dd0bf09c0..aee31098e44abbc2d12e1a944805bd44a70f7b3f 100644 (file)
--- a/vp10/common/mv.h
+++ b/vp10/common/mv.h
@@ -50,31 +50,34 @@ typedef struct mv32 {
 //
 // The ABS parameters are used to create an upper and lower bound
 // for each parameter. In other words, after a parameter is integerized
-// it is clamped between -(1 << ABS_XXX_BITS) and (1 << ABS_XXX_BITS)
+// it is clamped between -(1 << ABS_XXX_BITS) and (1 << ABS_XXX_BITS).
 //
-// XXX_PREC_DIFF and XXX_DECODE_FACTOR are computed once here to
-// prevent repetetive computation on the decoder side. These are
+// XXX_PREC_DIFF, XXX_ENCODE_FACTOR and XXX_DECODE_FACTOR
+// are computed once here to prevent repetitive
+// computation on the decoder side. These are
 // to allow the global motion parameters to be encoded in a lower
 // precision than the warped model precision. This means that they
 // need to be changed to warped precision when they are decoded.
 //
 // XX_MIN, XX_MAX are also computed to avoid repeated computation
 
-#define GM_TRANS_PREC_BITS        3
-#define GM_TRANS_PREC_DIFF        (WARPEDMODEL_PREC_BITS - GM_TRANS_PREC_BITS)
-#define GM_TRANS_DECODE_FACTOR    (1 << GM_TRANS_PREC_DIFF)
+#define GM_TRANS_PREC_BITS      5
+#define GM_TRANS_PREC_DIFF      (WARPEDMODEL_PREC_BITS - GM_TRANS_PREC_BITS)
+#define GM_TRANS_DECODE_FACTOR  (1 << GM_TRANS_PREC_DIFF)
+#define GM_TRANS_ENCODE_FACTOR  (1 / (GM_TRANS_DECODE_FACTOR))
 
-#define GM_ALPHA_PREC_BITS        5
-#define GM_ALPHA_PREC_DIFF        (WARPEDMODEL_PREC_BITS - GM_ALPHA_PREC_BITS)
-#define GM_ALPHA_DECODE_FACTOR    (1 << GM_ALPHA_PREC_DIFF)
+#define GM_ALPHA_PREC_BITS      5
+#define GM_ALPHA_PREC_DIFF      (WARPEDMODEL_PREC_BITS - GM_ALPHA_PREC_BITS)
+#define GM_ALPHA_DECODE_FACTOR  (1 << GM_ALPHA_PREC_DIFF)
+#define GM_ALPHA_ENCODE_FACTOR  (1 / (GM_ALPHA_DECODE_FACTOR))
 
-#define GM_ABS_ALPHA_BITS         5
-#define GM_ABS_TRANS_BITS         5
+#define GM_ABS_ALPHA_BITS       8
+#define GM_ABS_TRANS_BITS       8
 
-#define GM_TRANS_MAX              (1 << GM_ABS_TRANS_BITS)
-#define GM_ALPHA_MAX              (1 << GM_ABS_ALPHA_BITS)
-#define GM_TRANS_MIN              -GM_TRANS_MAX
-#define GM_ALPHA_MIN              -GM_ALPHA_MAX
+#define GM_TRANS_MAX            (1 << GM_ABS_TRANS_BITS)
+#define GM_ALPHA_MAX            (1 << GM_ABS_ALPHA_BITS)
+#define GM_TRANS_MIN            -GM_TRANS_MAX
+#define GM_ALPHA_MIN            -GM_ALPHA_MAX
 
 typedef enum {
   GLOBAL_ZERO = 0,

diff --git a/vp10/decoder/decodeframe.c b/vp10/decoder/decodeframe.c
index 3a51a48cee6736b675648eae08b3b2f8120d0332..ec04e5677e8de16124764baecfec5d7e91b2b96e 100644 (file)
--- a/vp10/decoder/decodeframe.c
+++ b/vp10/decoder/decodeframe.c
@@ -3473,6 +3473,7 @@ static void read_global_motion_params(Global_Motion_Params *params,
       params->motion_params.wmmat[5] =
           vp10_read_primitive_symmetric(r, GM_ABS_ALPHA_BITS) *
           GM_ALPHA_DECODE_FACTOR;
+      // fallthrough intended
     case GLOBAL_ROTZOOM:
       params->motion_params.wmmat[2] =
           (vp10_read_primitive_symmetric(r, GM_ABS_ALPHA_BITS) *
@@ -3480,6 +3481,7 @@ static void read_global_motion_params(Global_Motion_Params *params,
       params->motion_params.wmmat[3] =
           vp10_read_primitive_symmetric(r, GM_ABS_ALPHA_BITS) *
           GM_ALPHA_DECODE_FACTOR;
+      // fallthrough intended
     case GLOBAL_TRANSLATION:
       params->motion_params.wmmat[0] =
           vp10_read_primitive_symmetric(r, GM_ABS_TRANS_BITS) *

diff --git a/vp10/encoder/bitstream.c b/vp10/encoder/bitstream.c
index 558bafb511109dfc77ec6bb89858dae3ff54f546..e0427cc945c245d93011fd2eafb4164d8d3ed9f8 100644 (file)
--- a/vp10/encoder/bitstream.c
+++ b/vp10/encoder/bitstream.c
@@ -3200,19 +3200,29 @@ static void write_global_motion_params(Global_Motion_Params *params,
     case GLOBAL_ZERO:
       break;
     case GLOBAL_AFFINE:
-      vp10_write_primitive_symmetric(w, params->motion_params.wmmat[4],
+      vp10_write_primitive_symmetric(w, (params->motion_params.wmmat[4] *
+                                     GM_ALPHA_ENCODE_FACTOR) -
+                                     (1 << GM_ALPHA_PREC_BITS),
                                      GM_ABS_ALPHA_BITS);
-      vp10_write_primitive_symmetric(w, params->motion_params.wmmat[5],
+      vp10_write_primitive_symmetric(w, params->motion_params.wmmat[5] *
+                                     GM_ALPHA_ENCODE_FACTOR,
                                      GM_ABS_ALPHA_BITS);
+      // fallthrough intended
     case GLOBAL_ROTZOOM:
-      vp10_write_primitive_symmetric(w, params->motion_params.wmmat[2],
+      vp10_write_primitive_symmetric(w, (params->motion_params.wmmat[2] *
+                                     GM_ALPHA_ENCODE_FACTOR) -
+                                     (1 << GM_ALPHA_PREC_BITS),
                                      GM_ABS_ALPHA_BITS);
-      vp10_write_primitive_symmetric(w, params->motion_params.wmmat[3],
+      vp10_write_primitive_symmetric(w, params->motion_params.wmmat[3] *
+                                     GM_ALPHA_ENCODE_FACTOR,
                                      GM_ABS_ALPHA_BITS);
+      // fallthrough intended
     case GLOBAL_TRANSLATION:
-      vp10_write_primitive_symmetric(w, params->motion_params.wmmat[0],
+      vp10_write_primitive_symmetric(w, params->motion_params.wmmat[0] *
+                                     GM_TRANS_ENCODE_FACTOR,
                                      GM_ABS_TRANS_BITS);
-      vp10_write_primitive_symmetric(w, params->motion_params.wmmat[1],
+      vp10_write_primitive_symmetric(w, params->motion_params.wmmat[1] *
+                                     GM_TRANS_ENCODE_FACTOR,
                                      GM_ABS_TRANS_BITS);
       break;
     default:

diff --git a/vp10/encoder/encodeframe.c b/vp10/encoder/encodeframe.c
index ed7e14982ea5e32cdd6d752c985dd29aea288987..0389dcf27521ffe46c1c01fea4974c742d3a51ec 100644 (file)
--- a/vp10/encoder/encodeframe.c
+++ b/vp10/encoder/encodeframe.c
@@ -4549,18 +4549,20 @@ static void convert_to_params(double *H, TransformationType type,
                                               (1 << GM_TRANS_PREC_BITS) + 0.5);
   model->motion_params.wmmat[0] =
       clamp(model->motion_params.wmmat[0],
-            GM_TRANS_MIN, GM_TRANS_MAX);
+            GM_TRANS_MIN, GM_TRANS_MAX) *
+            GM_TRANS_DECODE_FACTOR;
   model->motion_params.wmmat[1] =
       clamp(model->motion_params.wmmat[1],
-            GM_TRANS_MIN, GM_TRANS_MAX);
+            GM_TRANS_MIN, GM_TRANS_MAX) *
+            GM_TRANS_DECODE_FACTOR;
 
   for (i = 2; i < n_params; ++i) {
     model->motion_params.wmmat[i] =
         (int) floor(H[i] *
-                    (1 << GM_ALPHA_PREC_BITS) + 0.5) -
-                    (!(i & 1) * (1 << GM_ALPHA_PREC_BITS));
+                    (1 << GM_ALPHA_PREC_BITS) + 0.5);
     model->motion_params.wmmat[i] = clamp(model->motion_params.wmmat[i],
-                                          GM_ALPHA_MIN, GM_ALPHA_MAX);
+                                          GM_ALPHA_MIN, GM_ALPHA_MAX) *
+                                          GM_ALPHA_DECODE_FACTOR;
     alpha_present |= (model->motion_params.wmmat[i] != 0);
   }
 
@@ -4579,6 +4581,7 @@ static void convert_model_to_params(double *H, TransformationType type,
   if (type > HOMOGRAPHY)
       convert_to_params(H, type, model);
   model->gmtype = get_gmtype(model);
+  model->motion_params.wmtype = gm_to_trans_type(model->gmtype);
 }
 #endif  // CONFIG_GLOBAL_MOTION
 
@@ -4610,7 +4613,7 @@ static void encode_frame_internal(VP10_COMP *cpi) {
     int frame;
     double H[9] = {0, 0, 0, 0, 0, 0, 0, 0, 1};
     for (frame = LAST_FRAME; frame <= ALTREF_FRAME; ++frame)
-      convert_model_to_params(H, ROTZOOM, &cm->global_motion[frame]);
+      convert_model_to_params(H, AFFINE, &cm->global_motion[frame]);
   }
 #endif  // CONFIG_GLOBAL_MOTION