diff --git a/av1/common/mv.h b/av1/common/mv.h
index 22a47f763c41f2ce18c65f87bdfbabff77be950c..a02d59866209ff9615c59f1b743b01659bf560bf 100644
--- a/av1/common/mv.h
+++ b/av1/common/mv.h
@@ -102,8 +102,8 @@ typedef struct {
#define GM_ALPHA_PREC_DIFF (WARPEDMODEL_PREC_BITS - GM_ALPHA_PREC_BITS)
#define GM_ALPHA_DECODE_FACTOR (1 << GM_ALPHA_PREC_DIFF)
-#define GM_ABS_ALPHA_BITS 18
-#define GM_ABS_TRANS_BITS 18
+#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)
diff --git a/av1/common/warped_motion.c b/av1/common/warped_motion.c
index 146a14d8ed6dd0f6e121c0c4e014c5b64029c4c1..2e550cb0d6fd9835bc8be47c6cdd76313ad52af9 100644
--- a/av1/common/warped_motion.c
+++ b/av1/common/warped_motion.c
@@ -95,11 +95,11 @@ void projectPointsAffine(int16_t *mat, int *points, int *proj, const int n,
WARPEDDIFF_PREC_BITS);
if (subsampling_y)
*(proj++) = ROUND_POWER_OF_TWO_SIGNED(
- mat[5] * 2 * x + mat[4] * 2 * y + mat[0] +
- (mat[5] + mat[4] - (1 << WARPEDMODEL_PREC_BITS)) / 2,
+ mat[4] * 2 * x + mat[5] * 2 * y + mat[0] +
+ (mat[4] + mat[5] - (1 << WARPEDMODEL_PREC_BITS)) / 2,
WARPEDDIFF_PREC_BITS + 1);
else
- *(proj++) = ROUND_POWER_OF_TWO_SIGNED(mat[5] * x + mat[4] * y + mat[0],
+ *(proj++) = ROUND_POWER_OF_TWO_SIGNED(mat[4] * x + mat[5] * y + mat[0],
WARPEDDIFF_PREC_BITS);
points += stride_points - 2;
proj += stride_proj - 2;
diff --git a/av1/decoder/decodeframe.c b/av1/decoder/decodeframe.c
index 6e52c79d947ab8e82f2b6c700562bb3cc6446874..031ddbc72d030fd780cce111fe785c6b3a8a2377 100644
--- a/av1/decoder/decodeframe.c
+++ b/av1/decoder/decodeframe.c
@@ -3411,12 +3411,12 @@ static void read_global_motion_params(Global_Motion_Params *params,
case GLOBAL_ZERO: break;
case GLOBAL_AFFINE:
params->motion_params.wmmat[2].as_mv.row =
+ (aom_read_primitive_symmetric(r, GM_ABS_ALPHA_BITS) *
+ GM_ALPHA_DECODE_FACTOR);
+ params->motion_params.wmmat[2].as_mv.col =
aom_read_primitive_symmetric(r, GM_ABS_ALPHA_BITS) *
GM_ALPHA_DECODE_FACTOR +
(1 << WARPEDMODEL_PREC_BITS);
- params->motion_params.wmmat[2].as_mv.col =
- (aom_read_primitive_symmetric(r, GM_ABS_ALPHA_BITS) *
- GM_ALPHA_DECODE_FACTOR);
// fallthrough intended
case GLOBAL_ROTZOOM:
params->motion_params.wmmat[1].as_mv.row =
diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index 49f1b44c38e12ad2c9dd3920b4df953e0bdec675..6578c0cffc9169058ce451ff37da812d71dfac92 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -3213,11 +3213,11 @@ static void write_global_motion_params(Global_Motion_Params *params,
case GLOBAL_ZERO: break;
case GLOBAL_AFFINE:
aom_write_primitive_symmetric(
- w, (params->motion_params.wmmat[2].as_mv.row >> GM_ALPHA_PREC_DIFF) -
- (1 << GM_ALPHA_PREC_BITS),
+ w, (params->motion_params.wmmat[2].as_mv.row >> GM_ALPHA_PREC_DIFF),
GM_ABS_ALPHA_BITS);
aom_write_primitive_symmetric(
- w, (params->motion_params.wmmat[2].as_mv.col >> GM_ALPHA_PREC_DIFF),
+ w, (params->motion_params.wmmat[2].as_mv.col >> GM_ALPHA_PREC_DIFF) -
+ (1 << GM_ALPHA_PREC_BITS),
GM_ABS_ALPHA_BITS);
// fallthrough intended
case GLOBAL_ROTZOOM:
diff --git a/av1/encoder/encodeframe.c b/av1/encoder/encodeframe.c
index 8796ac9c23614dc4b1d4ef15e87ac0102afb92e4..4b93ab65b4605b838a329de555c91e043b4c712e 100644
--- a/av1/encoder/encodeframe.c
+++ b/av1/encoder/encodeframe.c
@@ -4479,7 +4479,7 @@ static void refine_integerized_param(WarpedMotionParams *wm,
static void convert_to_params(double *H, TransformationType type,
int16_t *model) {
- int i;
+ int i, diag_value;
int alpha_present = 0;
int n_params = n_trans_model_params[type];
model[0] = (int16_t)floor(H[0] * (1 << GM_TRANS_PREC_BITS) + 0.5);
@@ -4489,11 +4489,13 @@ static void convert_to_params(double *H, TransformationType type,
model[1] = (int16_t)clamp(model[1], GM_TRANS_MIN, GM_TRANS_MAX) *
GM_TRANS_DECODE_FACTOR;
- // TODO(sarahparker) 1 should be subtracted here
for (i = 2; i < n_params; ++i) {
+ diag_value = ((i && 1) ? (1 << GM_ALPHA_PREC_BITS) : 0);
model[i] = (int16_t)floor(H[i] * (1 << GM_ALPHA_PREC_BITS) + 0.5);
- model[i] = (int16_t)clamp(model[i], GM_ALPHA_MIN, GM_ALPHA_MAX) *
- GM_ALPHA_DECODE_FACTOR;
+ model[i] =
+ (int16_t)(clamp(model[i] - diag_value, GM_ALPHA_MIN, GM_ALPHA_MAX) +
+ diag_value) *
+ GM_ALPHA_DECODE_FACTOR;
alpha_present |= (model[i] != 0);
}
diff --git a/av1/encoder/global_motion.h b/av1/encoder/global_motion.h
index aad8cc4f0b4b4c09da1a90044297225df5928606..fa4f79117c3c8737361788932aa80a253a56414c 100644
--- a/av1/encoder/global_motion.h
+++ b/av1/encoder/global_motion.h
@@ -17,7 +17,17 @@
extern "C" {
#endif
-// compute global motion parameters between two frames
+/*
+ Computes global motion parameters between two frames. The array
+ "params" should be length 9, where the first 2 slots are translation
+ parameters in (row, col) order, and the remaining slots correspond
+ to values in the transformation matrix of the corresponding motion
+ model. They are arranged in "params" such that values on the tx-matrix
+ diagonal have odd numbered indices so the folowing matrix:
+ A | B
+ C | D
+ would produce params = [trans row, trans col, B, A, C, D]
+*/
int compute_global_motion_feature_based(TransformationType type,
YV12_BUFFER_CONFIG *frm,
YV12_BUFFER_CONFIG *ref,
diff --git a/av1/encoder/ransac.c b/av1/encoder/ransac.c
index a3072bc0237cbaab1bd5862d7a7ce3a89974d9ec..81c1c21eb755688bd9c9a8687e42832591304447 100644
--- a/av1/encoder/ransac.c
+++ b/av1/encoder/ransac.c
@@ -615,8 +615,8 @@ static void denormalizeAffine(double *H, double *T1, double *T2) {
H[1] = Ha[2];
H[2] = Ha[1];
H[3] = Ha[0];
- H[4] = Ha[4];
- H[5] = Ha[3];
+ H[4] = Ha[3];
+ H[5] = Ha[4];
}
static void denormalizeRotZoom(double *H, double *T1, double *T2) {